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 <head>
  <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
  <title>Guidelines for Implementation: DASH-IF Ingest</title>
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<style data-fill-with="stylesheet">/******************************************************************************
 *                   Style sheet for the W3C specifications                   *
 *
 * Special classes handled by this style sheet include:
 *
 * Indices
 *   - .toc for the Table of Contents (<ol class="toc">)
 *     + <span class="secno"> for the section numbers
 *   - #toc for the Table of Contents (<nav id="toc">)
 *   - ul.index for Indices (<a href="#ref">term</a><span>, in §N.M</span>)
 *   - table.index for Index Tables (e.g. for properties or elements)
 *
 * Structural Markup
 *   - table.data for general data tables
 *     -> use 'scope' attribute, <colgroup>, <thead>, and <tbody> for best results !
 *     -> use <table class='complex data'> for extra-complex tables
 *     -> use <td class='long'> for paragraph-length cell content
 *     -> use <td class='pre'> when manual line breaks/indentation would help readability
 *   - dl.switch for switch statements
 *   - ol.algorithm for algorithms (helps to visualize nesting)
 *   - .figure and .caption (HTML4) and figure and figcaption (HTML5)
 *     -> .sidefigure for right-floated figures
 *   - ins/del
 *
 * Code
 *   - pre and code
 *
 * Special Sections
 *   - .note       for informative notes             (div, p, span, aside, details)
 *   - .example    for informative examples          (div, p, pre, span)
 *   - .issue      for issues                        (div, p, span)
 *   - .assertion  for assertions                    (div, p, span)
 *   - .advisement for loud normative statements     (div, p, strong)
 *   - .annoying-warning for spec obsoletion notices (div, aside, details)
 *
 * Definition Boxes
 *   - pre.def   for WebIDL definitions
 *   - table.def for tables that define other entities (e.g. CSS properties)
 *   - dl.def    for definition lists that define other entitles (e.g. HTML elements)
 *
 * Numbering
 *   - .secno for section numbers in .toc and headings (<span class='secno'>3.2</span>)
 *   - .marker for source-inserted example/figure/issue numbers (<span class='marker'>Issue 4</span>)
 *   - ::before styled for CSS-generated issue/example/figure numbers:
 *     -> Documents wishing to use this only need to add
 *        figcaption::before,
 *        .caption::before { content: "Figure "  counter(figure) " ";  }
 *        .example::before { content: "Example " counter(example) " "; }
 *        .issue::before   { content: "Issue "   counter(issue) " ";   }
 *
 * Header Stuff (ignore, just don't conflict with these classes)
 *   - .head for the header
 *   - .copyright for the copyright
 *
 * Miscellaneous
 *   - .overlarge for things that should be as wide as possible, even if
 *     that overflows the body text area. This can be used on an item or
 *     on its container, depending on the effect desired.
 *     Note that this styling basically doesn't help at all when printing,
 *     since A4 paper isn't much wider than the max-width here.
 *     It's better to design things to fit into a narrower measure if possible.
 *   - js-added ToC jump links (see fixup.js)
 *
 ******************************************************************************/

/******************************************************************************/
/*                                   Body                                     */
/******************************************************************************/

	body {
		counter-reset: example figure issue;

		/* Layout */
		max-width: 50em;               /* limit line length to 50em for readability   */
		margin: 0 auto;                /* center text within page                     */
		padding: 1.6em 1.5em 2em 50px; /* assume 16px font size for downlevel clients */
		padding: 1.6em 1.5em 2em calc(26px + 1.5em); /* leave space for status flag     */

		/* Typography */
		line-height: 1.5;
		font-family: sans-serif;
		widows: 2;
		orphans: 2;
		word-wrap: break-word;
		overflow-wrap: break-word;
		hyphens: auto;

		/* Colors */
		color: black;
		background: white top left fixed no-repeat;
		background-size: 25px auto;
	}


/******************************************************************************/
/*                         Front Matter & Navigation                          */
/******************************************************************************/

/** Header ********************************************************************/

	div.head { margin-bottom: 1em }
	div.head hr { border-style: solid; }

	div.head h1 {
		font-weight: bold;
		margin: 0 0 .1em;
		font-size: 220%;
	}

	div.head h2 { margin-bottom: 1.5em;}

/** W3C Logo ******************************************************************/

	.head .logo {
		float: right;
		margin: 0.4rem 0 0.2rem .4rem;
	}

	.head img[src*="logos/W3C"] {
		display: block;
		border: solid #1a5e9a;
		border-width: .65rem .7rem .6rem;
		border-radius: .4rem;
		background: #1a5e9a;
		color: white;
		font-weight: bold;
	}

	.head a:hover > img[src*="logos/W3C"],
	.head a:focus > img[src*="logos/W3C"] {
		opacity: .8;
	}

	.head a:active > img[src*="logos/W3C"] {
		background: #c00;
		border-color: #c00;
	}

	/* see also additional rules in Link Styling section */

/** Copyright *****************************************************************/

	p.copyright,
	p.copyright small { font-size: small }

/** Back to Top / ToC Toggle **************************************************/

	@media print {
		#toc-nav {
			display: none;
		}
	}
	@media not print {
		#toc-nav {
			position: fixed;
			z-index: 2;
			bottom: 0; left: 0;
			margin: 0;
			min-width: 1.33em;
			border-top-right-radius: 2rem;
			box-shadow: 0 0 2px;
			font-size: 1.5em;
			color: black;
		}
		#toc-nav > a {
			display: block;
			white-space: nowrap;

			height: 1.33em;
			padding: .1em 0.3em;
			margin: 0;

			background: white;
			box-shadow: 0 0 2px;
			border: none;
			border-top-right-radius: 1.33em;
			background: white;
		}
		#toc-nav > #toc-jump {
			padding-bottom: 2em;
			margin-bottom: -1.9em;
		}

		#toc-nav > a:hover,
		#toc-nav > a:focus {
			background: #f8f8f8;
		}
		#toc-nav > a:not(:hover):not(:focus) {
			color: #707070;
		}

		/* statusbar gets in the way on keyboard focus; remove once browsers fix */
		#toc-nav > a[href="#toc"]:not(:hover):focus:last-child {
			padding-bottom: 1.5rem;
		}

		#toc-nav:not(:hover) > a:not(:focus) > span + span {
			/* Ideally this uses :focus-within on #toc-nav */
			display: none;
		}
		#toc-nav > a > span + span {
			padding-right: 0.2em;
		}

		#toc-toggle-inline {
			vertical-align: 0.05em;
			font-size: 80%;
			color: gray;
			color: hsla(203,20%,40%,.7);
			border-style: none;
			background: transparent;
			position: relative;
		}
		#toc-toggle-inline:hover:not(:active),
		#toc-toggle-inline:focus:not(:active) {
			text-shadow: 1px 1px silver;
			top: -1px;
			left: -1px;
		}

		#toc-nav :active {
			color: #C00;
		}
	}

/** ToC Sidebar ***************************************************************/

	/* Floating sidebar */
	@media screen {
		body.toc-sidebar #toc {
			position: fixed;
			top: 0; bottom: 0;
			left: 0;
			width: 23.5em;
			max-width: 80%;
			max-width: calc(100% - 2em - 26px);
			overflow: auto;
			padding: 0 1em;
			padding-left: 42px;
			padding-left: calc(1em + 26px);
			background: inherit;
			background-color: #f7f8f9;
			z-index: 1;
			box-shadow: -.1em 0 .25em rgba(0,0,0,.1) inset;
		}
		body.toc-sidebar #toc h2 {
			margin-top: .8rem;
			font-variant: small-caps;
			font-variant: all-small-caps;
			text-transform: lowercase;
			font-weight: bold;
			color: gray;
			color: hsla(203,20%,40%,.7);
		}
		body.toc-sidebar #toc-jump:not(:focus) {
			width: 0;
			height: 0;
			padding: 0;
			position: absolute;
			overflow: hidden;
		}
	}
	/* Hide main scroller when only the ToC is visible anyway */
	@media screen and (max-width: 28em) {
		body.toc-sidebar {
			overflow: hidden;
		}
	}

	/* Sidebar with its own space */
	@media screen and (min-width: 78em) {
		body:not(.toc-inline) #toc {
			position: fixed;
			top: 0; bottom: 0;
			left: 0;
			width: 23.5em;
			overflow: auto;
			padding: 0 1em;
			padding-left: 42px;
			padding-left: calc(1em + 26px);
			background: inherit;
			background-color: #f7f8f9;
			z-index: 1;
			box-shadow: -.1em 0 .25em rgba(0,0,0,.1) inset;
		}
		body:not(.toc-inline) #toc h2 {
			margin-top: .8rem;
			font-variant: small-caps;
			font-variant: all-small-caps;
			text-transform: lowercase;
			font-weight: bold;
			color: gray;
			color: hsla(203,20%,40%,.7);
		}

		body:not(.toc-inline) {
			padding-left: 29em;
		}
		/* See also Overflow section at the bottom */

		body:not(.toc-inline) #toc-jump:not(:focus) {
			width: 0;
			height: 0;
			padding: 0;
			position: absolute;
			overflow: hidden;
		}
	}
	@media screen and (min-width: 90em) {
		body:not(.toc-inline) {
			margin: 0 4em;
		}
	}

/******************************************************************************/
/*                                Sectioning                                  */
/******************************************************************************/

/** Headings ******************************************************************/

	h1, h2, h3, h4, h5, h6, dt {
		page-break-after: avoid;
		page-break-inside: avoid;
		font: 100% sans-serif;   /* Reset all font styling to clear out UA styles */
		font-family: inherit;    /* Inherit the font family. */
		line-height: 1.2;        /* Keep wrapped headings compact */
		hyphens: manual;         /* Hyphenated headings look weird */
	}

	h2, h3, h4, h5, h6 {
		margin-top: 3rem;
	}

	h1, h2, h3 {
		color: #005A9C;
		background: transparent;
	}

	h1 { font-size: 170%; }
	h2 { font-size: 140%; }
	h3 { font-size: 120%; }
	h4 { font-weight: bold; }
	h5 { font-style: italic; }
	h6 { font-variant: small-caps; }
	dt { font-weight: bold; }

/** Subheadings ***************************************************************/

	h1 + h2,
	#subtitle {
		/* #subtitle is a subtitle in an H2 under the H1 */
		margin-top: 0;
	}
	h2 + h3,
	h3 + h4,
	h4 + h5,
	h5 + h6 {
		margin-top: 1.2em; /* = 1 x line-height */
	}

/** Section divider ***********************************************************/

	:not(.head) > hr {
		font-size: 1.5em;
		text-align: center;
		margin: 1em auto;
		height: auto;
		border: transparent solid 0;
		background: transparent;
	}
	:not(.head) > hr::before {
		content: "\2727\2003\2003\2727\2003\2003\2727";
	}

/******************************************************************************/
/*                            Paragraphs and Lists                            */
/******************************************************************************/

	p {
		margin: 1em 0;
	}

	dd > p:first-child,
	li > p:first-child {
		margin-top: 0;
	}

	ul, ol {
		margin-left: 0;
		padding-left: 2em;
	}

	li {
		margin: 0.25em 0 0.5em;
		padding: 0;
	}

	dl dd {
		margin: 0 0 .5em 2em;
	}

	.head dd + dd { /* compact for header */
		margin-top: -.5em;
	}

	/* Style for algorithms */
	ol.algorithm ol:not(.algorithm),
	.algorithm > ol ol:not(.algorithm) {
	 border-left: 0.5em solid #DEF;
	}

	/* Put nice boxes around each algorithm. */
	[data-algorithm]:not(.heading) {
	  padding: .5em;
	  border: thin solid #ddd; border-radius: .5em;
	  margin: .5em calc(-0.5em - 1px);
	}
	[data-algorithm]:not(.heading) > :first-child {
	  margin-top: 0;
	}
	[data-algorithm]:not(.heading) > :last-child {
	  margin-bottom: 0;
	}

	/* Style for switch/case <dl>s */
	dl.switch > dd > ol.only,
	dl.switch > dd > .only > ol {
	 margin-left: 0;
	}
	dl.switch > dd > ol.algorithm,
	dl.switch > dd > .algorithm > ol {
	 margin-left: -2em;
	}
	dl.switch {
	 padding-left: 2em;
	}
	dl.switch > dt {
	 text-indent: -1.5em;
	 margin-top: 1em;
	}
	dl.switch > dt + dt {
	 margin-top: 0;
	}
	dl.switch > dt::before {
	 content: '\21AA';
	 padding: 0 0.5em 0 0;
	 display: inline-block;
	 width: 1em;
	 text-align: right;
	 line-height: 0.5em;
	}

/** Terminology Markup ********************************************************/


/******************************************************************************/
/*                                 Inline Markup                              */
/******************************************************************************/

/** Terminology Markup ********************************************************/
	dfn   { /* Defining instance */
		font-weight: bolder;
	}
	a > i { /* Instance of term */
		font-style: normal;
	}
	dt dfn code, code.idl {
		font-size: medium;
	}
	dfn var {
		font-style: normal;
	}

/** Change Marking ************************************************************/

	del { color: red;  text-decoration: line-through; }
	ins { color: #080; text-decoration: underline;    }

/** Miscellaneous improvements to inline formatting ***************************/

	sup {
		vertical-align: super;
		font-size: 80%
	}

/******************************************************************************/
/*                                    Code                                    */
/******************************************************************************/

/** General monospace/pre rules ***********************************************/

	pre, code, samp {
		font-family: Menlo, Consolas, "DejaVu Sans Mono", Monaco, monospace;
		font-size: .9em;
		page-break-inside: avoid;
		hyphens: none;
		text-transform: none;
	}
	pre code,
	code code {
		font-size: 100%;
	}

	pre {
		margin-top: 1em;
		margin-bottom: 1em;
		overflow: auto;
	}

/** Inline Code fragments *****************************************************/

  /* Do something nice. */

/******************************************************************************/
/*                                    Links                                   */
/******************************************************************************/

/** General Hyperlinks ********************************************************/

	/* We hyperlink a lot, so make it less intrusive */
	a[href] {
		color: #034575;
		text-decoration: none;
		border-bottom: 1px solid #707070;
		/* Need a bit of extending for it to look okay */
		padding: 0 1px 0;
		margin: 0 -1px 0;
	}
	a:visited {
		border-bottom-color: #BBB;
	}

	/* Use distinguishing colors when user is interacting with the link */
	a[href]:focus,
	a[href]:hover {
		background: #f8f8f8;
		background: rgba(75%, 75%, 75%, .25);
		border-bottom-width: 3px;
		margin-bottom: -2px;
	}
	a[href]:active {
		color: #C00;
		border-color: #C00;
	}

	/* Backout above styling for W3C logo */
	.head .logo,
	.head .logo a {
		border: none;
		text-decoration: none;
		background: transparent;
	}

/******************************************************************************/
/*                                    Images                                  */
/******************************************************************************/

	img {
		border-style: none;
	}

	/* For autogen numbers, add
	   .caption::before, figcaption::before { content: "Figure " counter(figure) ". "; }
	*/

	figure, .figure, .sidefigure {
		page-break-inside: avoid;
		text-align: center;
		margin: 2.5em 0;
	}
	.figure img,    .sidefigure img,    figure img,
	.figure object, .sidefigure object, figure object {
		max-width: 100%;
		margin: auto;
	}
	.figure pre, .sidefigure pre, figure pre {
		text-align: left;
		display: table;
		margin: 1em auto;
	}
	.figure table, figure table {
		margin: auto;
	}
	@media screen and (min-width: 20em) {
		.sidefigure {
			float: right;
			width: 50%;
			margin: 0 0 0.5em 0.5em
		}
	}
	.caption, figcaption, caption {
		font-style: italic;
		font-size: 90%;
	}
	.caption::before, figcaption::before, figcaption > .marker {
		font-weight: bold;
	}
	.caption, figcaption {
		counter-increment: figure;
	}

	/* DL list is indented 2em, but figure inside it is not */
	dd > .figure, dd > figure { margin-left: -2em }

/******************************************************************************/
/*                             Colored Boxes                                  */
/******************************************************************************/

	.issue, .note, .example, .assertion, .advisement, blockquote {
		padding: .5em;
		border: .5em;
		border-left-style: solid;
		page-break-inside: avoid;
	}
	span.issue, span.note {
		padding: .1em .5em .15em;
		border-right-style: solid;
	}

	.issue,
	.note,
	.example,
	.advisement,
	.assertion,
	blockquote {
		margin: 1em auto;
	}
	.note  > p:first-child,
	.issue > p:first-child,
	blockquote > :first-child {
		margin-top: 0;
	}
	blockquote > :last-child {
		margin-bottom: 0;
	}

/** Blockquotes ***************************************************************/

	blockquote {
		border-color: silver;
	}

/** Open issue ****************************************************************/

	.issue {
		border-color: #E05252;
		background: #FBE9E9;
		counter-increment: issue;
		overflow: auto;
	}
	.issue::before, .issue > .marker {
		text-transform: uppercase;
		color: #AE1E1E;
		padding-right: 1em;
		text-transform: uppercase;
	}
	/* Add .issue::before { content: "Issue " counter(issue) " "; } for autogen numbers,
	   or use class="marker" to mark up the issue number in source. */

/** Example *******************************************************************/

	.example {
		border-color: #E0CB52;
		background: #FCFAEE;
		counter-increment: example;
		overflow: auto;
		clear: both;
	}
	.example::before, .example > .marker {
		text-transform: uppercase;
		color: #827017;
		min-width: 7.5em;
		display: block;
	}
	/* Add .example::before { content: "Example " counter(example) " "; } for autogen numbers,
	   or use class="marker" to mark up the example number in source. */

/** Non-normative Note ********************************************************/

	.note {
		border-color: #52E052;
		background: #E9FBE9;
		overflow: auto;
	}

	.note::before, .note > .marker,
	details.note > summary::before,
	details.note > summary > .marker {
		text-transform: uppercase;
		display: block;
		color: hsl(120, 70%, 30%);
	}
	/* Add .note::before { content: "Note"; } for autogen label,
	   or use class="marker" to mark up the label in source. */

	details.note > summary {
		display: block;
		color: hsl(120, 70%, 30%);
	}
	details.note[open] > summary {
		border-bottom: 1px silver solid;
	}

/** Assertion Box *************************************************************/
	/*  for assertions in algorithms */

	.assertion {
		border-color: #AAA;
		background: #EEE;
	}

/** Advisement Box ************************************************************/
	/*  for attention-grabbing normative statements */

	.advisement {
		border-color: orange;
		border-style: none solid;
		background: #FFEECC;
	}
	strong.advisement {
		display: block;
		text-align: center;
	}
	.advisement > .marker {
		color: #B35F00;
	}

/** Spec Obsoletion Notice ****************************************************/
	/* obnoxious obsoletion notice for older/abandoned specs. */

	details {
		display: block;
	}
	summary {
		font-weight: bolder;
	}

	.annoying-warning:not(details),
	details.annoying-warning:not([open]) > summary,
	details.annoying-warning[open] {
		background: #fdd;
		color: red;
		font-weight: bold;
		padding: .75em 1em;
		border: thick red;
		border-style: solid;
		border-radius: 1em;
	}
	.annoying-warning :last-child {
		margin-bottom: 0;
	}

@media not print {
	details.annoying-warning[open] {
		position: fixed;
		left: 1em;
		right: 1em;
		bottom: 1em;
		z-index: 1000;
	}
}

	details.annoying-warning:not([open]) > summary {
		text-align: center;
	}

/** Entity Definition Boxes ***************************************************/

	.def {
		padding: .5em 1em;
		background: #DEF;
		margin: 1.2em 0;
		border-left: 0.5em solid #8CCBF2;
	}

/******************************************************************************/
/*                                    Tables                                  */
/******************************************************************************/

	th, td {
		text-align: left;
		text-align: start;
	}

/** Property/Descriptor Definition Tables *************************************/

	table.def {
		/* inherits .def box styling, see above */
		width: 100%;
		border-spacing: 0;
	}

	table.def td,
	table.def th {
		padding: 0.5em;
		vertical-align: baseline;
		border-bottom: 1px solid #bbd7e9;
	}

	table.def > tbody > tr:last-child th,
	table.def > tbody > tr:last-child td {
		border-bottom: 0;
	}

	table.def th {
		font-style: italic;
		font-weight: normal;
		padding-left: 1em;
		width: 3em;
	}

	/* For when values are extra-complex and need formatting for readability */
	table td.pre {
		white-space: pre-wrap;
	}

	/* A footnote at the bottom of a def table */
	table.def           td.footnote {
		padding-top: 0.6em;
	}
	table.def           td.footnote::before {
		content: " ";
		display: block;
		height: 0.6em;
		width: 4em;
		border-top: thin solid;
	}

/** Data tables (and properly marked-up index tables) *************************/
	/*
		 <table class="data"> highlights structural relationships in a table
		 when correct markup is used (e.g. thead/tbody, th vs. td, scope attribute)

		 Use class="complex data" for particularly complicated tables --
		 (This will draw more lines: busier, but clearer.)

		 Use class="long" on table cells with paragraph-like contents
		 (This will adjust text alignment accordingly.)
		 Alternately use class="longlastcol" on tables, to have the last column assume "long".
	*/

	table {
		word-wrap: normal;
		overflow-wrap: normal;
		hyphens: manual;
	}

	table.data,
	table.index {
		margin: 1em auto;
		border-collapse: collapse;
		border: hidden;
		width: 100%;
	}
	table.data caption,
	table.index caption {
		max-width: 50em;
		margin: 0 auto 1em;
	}

	table.data td,  table.data th,
	table.index td, table.index th {
		padding: 0.5em 1em;
		border-width: 1px;
		border-color: silver;
		border-top-style: solid;
	}

	table.data thead td:empty {
		padding: 0;
		border: 0;
	}

	table.data  thead,
	table.index thead,
	table.data  tbody,
	table.index tbody {
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/******************************************************************************/
/*                                  Indices                                   */
/******************************************************************************/


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/*                                    Print                                   */
/******************************************************************************/

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/******************************************************************************/
/*                                    Legacy                                  */
/******************************************************************************/

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/******************************************************************************/
/*                             Overflow Control                               */
/******************************************************************************/

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 <body class="h-entry">
  <div class="head">
   <p data-fill-with="logo"><a href="https://dashif.org/"><img src="Images/DASH-IF.png"></a> </p>
   <h1 class="p-name no-ref" id="title">Guidelines for Implementation: DASH-IF Ingest</h1>
   <h2 class="no-num no-toc no-ref heading settled" id="subtitle"><span class="content">Living Document, <time class="dt-updated" datetime="2018-12-17">17 December 2018</time></span></h2>
   <div data-fill-with="spec-metadata">
    <dl>
     <dt>This version:
     <dd><a class="u-url" href="https://dashif.org/guidelines/">https://dashif.org/guidelines/</a>
     <dt>Issue Tracking:
     <dd><a href="https://github.com/Dash-Industry-Forum/Ingest/issues">GitHub</a>
     <dt class="editor">Editors:
     <dd class="editor p-author h-card vcard"><span class="p-name fn">DASH IOP Ingest TF</span>
     <dd class="editor p-author h-card vcard"><span class="p-name fn"></span>
    </dl>
   </div>
   <div data-fill-with="warning"></div>
   <hr title="Separator for header">
  </div>
  <div data-fill-with="at-risk"></div>
  <nav data-fill-with="table-of-contents" id="toc">
   <h2 class="no-num no-toc no-ref" id="contents">Table of Contents</h2>
   <ol class="toc" role="directory">
    <li>
     <a href="#IngestSpec"><span class="secno">1</span> <span class="content">Specification: Live Media and Metadata Ingest</span></a>
     <ol class="toc">
      <li><a href="#Abstract"><span class="secno">1.1</span> <span class="content">Abstract</span></a>
      <li><a href="#CopyRights"><span class="secno">1.2</span> <span class="content">Copyright Notice and Disclaimer</span></a>
     </ol>
    <li><a href="#Introduction"><span class="secno">2</span> <span class="content">Introduction</span></a>
    <li><a href="#conventions"><span class="secno">3</span> <span class="content">Conventions and Terminology</span></a>
    <li><a href="#workflow_and_use_cases"><span class="secno">4</span> <span class="content">Media Ingest Workflows</span></a>
    <li><a href="#general"><span class="secno">5</span> <span class="content">General Ingest Protocol Behavior</span></a>
    <li><a href="#profile_1_general"><span class="secno">6</span> <span class="content">Profile 1: Fragmented MPEG-4 Ingest General Considerations</span></a>
    <li>
     <a href="#profile_1"><span class="secno">7</span> <span class="content">Profile 1: Fragmented MPEG-4 Ingest Protocol Behavior #</span></a>
     <ol class="toc">
      <li><a href="#general_Protocol_Requirements_p1"><span class="secno">7.1</span> <span class="content">General Protocol Requirements</span></a>
      <li><a href="#Requirements_for_formatting_Media_Tracks"><span class="secno">7.2</span> <span class="content">Requirements for formatting Media Tracks</span></a>
      <li><a href="#timed_text_and_subtitle_streams"><span class="secno">7.3</span> <span class="content">Requirements for Timed Text Captions and Subtitle Streams</span></a>
      <li><a href="#timed_metadata"><span class="secno">7.4</span> <span class="content">Requirements for Timed Metadata</span></a>
      <li><a href="#failover"><span class="secno">7.5</span> <span class="content">Requirements for Media Processing Entity Failover</span></a>
      <li><a href="#failover_source"><span class="secno">7.6</span> <span class="content">Requirements for Live Media Source Failover</span></a>
     </ol>
    <li><a href="#dash_ingest"><span class="secno">8</span> <span class="content">Profile 2: DASH and HLS Ingest General Considerations</span></a>
    <li>
     <a href="#Dash_ingest_behavior"><span class="secno">9</span> <span class="content">profile 2: DASH Ingest Protocol Behavior</span></a>
     <ol class="toc">
      <li><a href="#Dash_ingest_behavior_reqs"><span class="secno">9.1</span> <span class="content">General Protocol Requirements</span></a>
      <li><a href="#Dash_ingest_behavior_media_track"><span class="secno">9.2</span> <span class="content">Requirements for Formatting Media Tracks</span></a>
      <li><a href="#Dash_ingest_behavior_text_track"><span class="secno">9.3</span> <span class="content">Requirements for Timed Text Captions and Subtitle stream</span></a>
      <li><a href="#Dash_ingest_behavior_meta_track"><span class="secno">9.4</span> <span class="content">Requirements for Timed Metadata</span></a>
      <li><a href="#Dash_ingest_behavior_fail_track"><span class="secno">9.5</span> <span class="content">Requirements for Media Processing Entity Failover</span></a>
      <li><a href="#Dash_ingest_behavior_fail_source_track"><span class="secno">9.6</span> <span class="content">Requirements for Live Media Source Failover</span></a>
     </ol>
    <li><a href="#security"><span class="secno">10</span> <span class="content">Security Considerations</span></a>
    <li><a href="#iana"><span class="secno">11</span> <span class="content">IANA Considerations</span></a>
    <li><a href="#contrib"><span class="secno">12</span> <span class="content">Contributors</span></a>
    <li>
     <a href="#references_custom"><span class="secno">13</span> <span class="content">References</span></a>
     <ol class="toc">
      <li><a href="#references-url"><span class="secno">13.1</span> <span class="content">URL References</span></a>
     </ol>
    <li><a href="#Authors"><span class="secno">14</span> <span class="content">Author’s Address</span></a>
    <li><a href="#conformance"><span class="secno"></span> <span class="content"> Conformance</span></a>
    <li>
     <a href="#index"><span class="secno"></span> <span class="content">Index</span></a>
     <ol class="toc">
      <li><a href="#index-defined-here"><span class="secno"></span> <span class="content">Terms defined by this specification</span></a>
     </ol>
    <li>
     <a href="#references"><span class="secno"></span> <span class="content">References</span></a>
     <ol class="toc">
      <li><a href="#normative"><span class="secno"></span> <span class="content">Normative References</span></a>
      <li><a href="#informative"><span class="secno"></span> <span class="content">Informative References</span></a>
     </ol>
   </ol>
  </nav>
  <main>
   <h2 class="heading settled" data-level="1" id="IngestSpec"><span class="secno">1. </span><span class="content">Specification: Live Media and Metadata Ingest</span><a class="self-link" href="#IngestSpec"></a></h2>
   <h3 class="heading settled" data-level="1.1" id="Abstract"><span class="secno">1.1. </span><span class="content">Abstract</span><a class="self-link" href="#Abstract"></a></h3>
   <p>This draft presents a specification for ingesting media from
   a live source downstream.  Two profiles are defined.
   The first profile is based on the fragmented 
   MPEG-4 format. In this case the final media streaming 
   presentation is generated downstream. The second profile 
   enables ingest of media streaming presentations based 
   on MPEG DASH and HLS directly using a common media format. 
   Details on carriage of metadata markers, timed text,  
   subtitles and encryption specific metadata are also included.</p>
   <h3 class="heading settled" data-level="1.2" id="CopyRights"><span class="secno">1.2. </span><span class="content">Copyright Notice and Disclaimer</span><a class="self-link" href="#CopyRights"></a></h3>
   <p>Please review these documents
   carefully, as they describe your rights and restrictions with  
   respect to this document.  Code Components extracted from this  
   document must include Simplified BSD License text as described  
   in Section 4.e of the Trust Legal Provisions and are provided  
   without warranty as described in the Simplified BSD License</p>
   <p>This is a document made available by DASH-IF. The technology
embodied in this document may involve the use of intellectual
property rights, including patents and patent applications owned 
or controlled by any of the authors or developers of this document. 
No patent license, either implied or express, is granted to you by 
this document. DASH-IF has made no search or investigation for such 
rights and DASH-IF disclaims any duty to do so. The rights and obligations
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 forth and defined in the DASH-IF Bylaws and IPR Policy including, 
 but not limited to, patent and other intellectual property license 
 rights and obligations. A copy of the DASH-IF Bylaws and IPR Policy 
 can be obtained at http://dashif.org/.</p>
   <p>The material contained herein is provided on an AS IS basis and to the
maximum extent permitted by applicable law, this material is provided   
AS IS, and the authors and developers of this material and DASH-IF   
hereby disclaim all other warranties and conditions, either express, 
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of fitness for a particular purpose, of accuracy or completeness of responses, 
of workmanlike effort, and of lack of negligence.
In addition, this document may include references to documents and/or   
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Those third party documents and technologies may be subject to third party   
rules and licensing terms. No intellectual property license, either implied or express,
to any third party material is granted to you by this document or DASH-IF.   
DASH-IF makes no any warranty whatsoever for such third party material.</p>
   <h2 class="heading settled" data-level="2" id="Introduction"><span class="secno">2. </span><span class="content">Introduction</span><a class="self-link" href="#Introduction"></a></h2>
   <p>This document describes a specification for ingesting
   encoded media content from a ingest source such as a  
   live video encoder downstream, for example 
   towards distributed media processing entities. 
   Examples of such entities include media packagers, 
   publishing points, streaming origins and 
   content delivery networks.  
   The combination of ingest sources ingesting  
   media and distributed media processing entities  
   is important in practical video streaming deployments.  
   In such deployments, interoperability between  
   ingest sources and downstream processing  
   entities can be challenging.  
   This challenge comes from the fact that  
   there are multiple levels of interoperability  
   that need to be adressed and achieved.</p>
   <p>For example, the network protocol for transmission
   of data and the setup of the connectivity are important.  
   This includes schemes for establishing the ingest  
   connection, handling disconnections and failures,  
   procedures for repeatedly sending and receving  
   the data, and timely resolution of hostnames</p>
   <p>A second level of interoperability lies
   in the media container and coded media formats.  
   The Moving Picture Experts Group defined several media  
   container formats such as <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> and [!MPEG2TS]] 
   which are widely adopted and well supported.  
   However, these are general purpose formats,  
   targetting several different application areas.  
   To do so they provide many different profiles and options.  
   Detailed operability is often achieved through  
   other application standards such as those for  
   the broadcast or storage. In addition, the codec  
   and profile used, e.g. <a data-link-type="biblio" href="#biblio-mpeghevc">[MPEGHEVC]</a> is an important  
   interoperability point that itself also  
   has different profiles.</p>
   <p>A third level, is the way metadata is
   inserted in streams which can be a source  
   of interoperability issues, especially for live  
   content that needs such metadata to signal  
   opportunities for signalling ad insertion,  
   or other metadata like timed graphics.  Examples  
   of such metadata include <a data-link-type="biblio" href="#biblio-scte35">[SCTE35]</a> markers which  
   are often found in broadcast streams and other  
   metadata like ID3 tags <a data-link-type="biblio" href="#biblio-id3v2">[ID3v2]</a>.</p>
   <p>Fourth, for live media handling the timeline
   of the presentation consistently is important.  
   This includes correct sampling of media, avoiding  
   timeline discontinuities and  synchronizing  
   timestamps attached by different ingest sources
   such as audio and video.</p>
   <p>Fifth, in streaming workflows it is important
   to have support for failovers of both the live sources  
   and the media processing entities. This is important  
   to avoid interruptions of 24/7 live services such  
   as Internet television where components can fail.  
   In practical deployments, multiple ingest sources  
   and media processing entities are used. This requires  
   the multiple ingest sources and media processing to  
   work together in a redundant workflow where  
   some of the components might fail.</p>
   <p>This document provides a specification
   for establishing this interoperability point. 
   The approaches are based on known standardized  
   technologies and have been tested and deployed  
   in several streaming large scale streaming  
   deployments. Two key workflows have been  
   identified for which two different media  
   ingest profiles will be detailed.</p>
   <p>In first workflow, encoded media is ingested
   downstream for further processing of the media.  
   Examples of such media processing could be any  
   media transformation such as packaging,  
   encrypting or transcoding the stream.  
   Other operations could include watermarking,  
   content insertion and generating streaming manifests  
   based on <a data-link-type="biblio" href="#biblio-mpegdash">[MPEGDASH]</a> or HLS <a data-link-type="biblio" href="#biblio-rfc8216">[RFC8216]</a>. What is typical  
   of these operations is that they actively inspect,  
   or modify the media content and may  
   generate new derived media content.  
   In this workflow it is is important  
   to convey mediadata and metadata that  
   assists such active media processing operations.  
   This is workflow type is adressed  
   in the first profile fmp4 ingest.</p>
   <p>In the second workflow, the encoded media is ingested
   into an entity that does none or very minimal inspection  
   or modification of the media content. The main aim  
   of such processing entities often lies in storage,  
   caching and delivery of the media content. An example  
   of such an entity is a Content Delivery Network (CDN)  
   for delivering and caching Internet content.  
   Content delivery networks are often designed for  
   Internet content like web pages and might  
   not be aware of media specific aspects. In fact, streaming  
   protocols like MPEG DASH and HTTP Live Streaming have been  
   developed with re-use of such a media agnostic  
   Content Delivery Networks in mind. For ingesting  
   encoded media into a content delivery network it  
   is important to have the media presentation in a form  
   that is very close or matching to the format  
   that the clients need to playback the presentation,  
   as changing or complementing the media presentation  
   will be difficult. This second workflow is addressed  
   in profile 2 DASH and HLS ingest.</p>
<pre class="highlight">Diagram 1: Example with media ingest in profile 1

============       ==============      ==============
||        || ingest||  Active  || HLS  || Content  ||  HLS
|| ingest ||====>>>||processing||===>>>|| Delivery ||==>>>Client
|| source ||       || entity   || DASH || Network  ||  DASH
============       ==============      ==============
   
</pre>
<pre class="highlight">Diagram 2: Example with media ingest in profile 2
 
============       ==============      
||        || ingest|| Content  ||   HLS/DASH
|| ingest ||====>>>||Delivery  ||==>>>> Client
|| source ||       || Network  ||  
============       ============== 
</pre>
   <p>Diagram 1 shows the workflow with a live media ingest from a
   ingest source towards an active media processing entity.   
   In the example in diagram 1 the media processing entity  
   prepares the final media presentation for the client  
   that is delivered by the Content Delivery Network to a client.</p>
   <p>Diagram 2 shows the example in workflow 2 were content
   is ingested directly into a Content Delivery Network.  
   The content delivery network enables the delivery to the client.</p>
   <p>An example of a media ingest protocol
   is the ingest part of Microsoft Smooth   
   Streaming protocol <a data-link-type="dfn" href="#ms-sstr" id="ref-for-ms-sstr">MS-SSTR</a>. This protocol   
   connects live encoders to the Microsoft Smooth   
   Streaming server and to the Microsoft Azure cloud.   
   This protocol has shown to be robust, flexible and   
   easy to implement in live encoders. In addition it   
   provided features for high availability and   
   server side redundancy.</p>
   <p>The first profile fmp4 ingest relating to workflow 1
   advances over the smooth ingest procotol   
   including lessons learned over the last   
   ten years after the initial deployment of    
   smooth streaming in 2009 and several advances   
   on signalling of information   
   such as timed metadata markers for content insertion.   
   In addition, it incorporates the latest media formats   
   and protocols, making it ready for current and   
   next generation media codecs such as <a data-link-type="biblio" href="#biblio-mpeghevc">[MPEGHEVC]</a> and protocols like MPEG DASH <a data-link-type="biblio" href="#biblio-mpegdash">[MPEGDASH]</a>.
   In addition, to address the sub profiling 
   of exising media containers <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> is referenced.</p>
   <p>A second profile DASH and HLS ingest
   is included for ingest of media   
   streaming presentations to entities were    
   the media is not altered actively, and further   
   media processing perhaps restricted to the manifests.   
   A key idea of this part of the specification is to re-use   
   the similarities of MPEG DASH <a data-link-type="biblio" href="#biblio-mpegdash">[MPEGDASH]</a> and HLS <a data-link-type="biblio" href="#biblio-rfc8216">[RFC8216]</a> protocols   
   to enable a simultaneous ingest of media   
   presentations of these two formats using   
   common media segments such as based on <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> and <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> formats. In addition, in this   
   approach naming is important to enable direct   
   processing and storage of the presentation.</p>
   <p>Based on our experience we present
   these two separately.
   We made this decision as it will   
   reduce a lot of overhead in the   
   information that needs to be signalled   
   compared to having both profiles   
   combined into one, as was the case   
   in a prior version of this draft.</p>
   <p>We further motivate the specification
   in this document supporting using   
   HTTP 1.1 <a data-link-type="biblio" href="#biblio-rfc7235">[RFC7235]</a> and <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> a bit more.   
   We believe that Smooth streaming <a data-link-type="dfn" href="#ms-sstr" id="ref-for-ms-sstr①">MS-SSTR</a> and HLS <a data-link-type="biblio" href="#biblio-rfc8216">[RFC8216]</a> have shown that HTTP usage   
   can survive the Internet ecosystem for   
   media delivery. In addition, HTTP based   
   ingest fits well with current HTTP   
   based streaming protocols including <a data-link-type="biblio" href="#biblio-mpegdash">[MPEGDASH]</a>.   
   In addition, there is good support for HTTP   
   middleboxes and HTTP routing available   
   making it easier to debug and trace errors.   
   The HTTP POST provides a push based   
   method for delivery for pusing the   
   live content when available.</p>
   <p>The binary media format for conveying
   the media is based on fragmented MPEG-4 as  
   specified in <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a>. 
   A key benefit of this  format is that it 
   allows easy identification  
   of stream boundaries, enabling switching, redundancy,  
   re-transmission resulting in a good fit with the current  
   Internet infrastructures. Many problems in  
   practical streaming deployment often deal  
   with issues related to the binary  
   media format. We believe that the fragmented  
   MPEG-4 will make things easier  
   and that the industry is already heading  
   in this direction following recent specifications  
   like <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> and HLS <a data-link-type="biblio" href="#biblio-rfc8216">[RFC8216]</a>.</p>
   <p>Regarding the transports protocol, in future versions,
   alternative transport protocols could be considered  
   advancing over HTTP 1.1 or TCP. 
   We believe the proposed media format  
   will provide the same benefits with other transports  
   protocols. Our view is that for current and near future  
   deployments using <a data-link-type="biblio" href="#biblio-rfc7235">[RFC7235]</a> is still a good approach.</p>
   <p>The document is structured as follows, in section 3
   we present the conventions and terminology used throughout   
   this document. In section 4 we present use cases and   
   workflows related to media ingest and the two profiles   
   presented. Sections 5-9 will detail the protocol and   
   the two different profiles.</p>
   <h2 class="heading settled" data-level="3" id="conventions"><span class="secno">3. </span><span class="content">Conventions and Terminology</span><a class="self-link" href="#conventions"></a></h2>
   <p>The following terminology is used in the rest of this document.</p>
   <p>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this    
   document are to be interpreted as described in BCP 14, RFC 2119 <a data-link-type="biblio" href="#biblio-rfc2119">[RFC2119]</a>.</p>
   <p>ISOBMFF: the ISO Base Media File Format specified in <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a>.</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="ingest-stream"><strong>Ingest Stream</strong></dfn>:
            the stream of media produced by the live source  
            transmitted to the media processing entity.</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="live-stream-event"><strong>Live Stream Event</strong></dfn>:
            the total live stream for the ingest.  
            (Live) encoder: entity performing live  
            encoding and producing a high quality live stream,  
            can serve as ingest source</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="ingest-source"><strong>Ingest source</strong></dfn>:
            a media source ingesting media content  
            , typically a live encoder but not restricted  
            to this.</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="Publishing point" data-noexport id="publishing-point"><strong>Publishing point</strong> </dfn>:
              entity used to publish the media content,  
              consumes/receives the incoming media <a data-link-type="dfn" href="#ingest-stream" id="ref-for-ingest-stream">ingest stream</a></p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="media-processing-entity"><strong>Media processing entity</strong></dfn>:
            entity used to process the media content,  
            receives/consumes a media [=ingest stream].</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="connection"><strong>Connection</strong></dfn>:
              a connection setup between two hosts, typically the  
              media ingest source and media processing entity.</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="ftyp"><strong>ftyp</strong></dfn>:
             the filetype and compatibility "ftyp" box as described  
             in the ISOBMFF <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> that describes the "brand"</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="moov"><strong>moov</strong></dfn>:
             the container box for all metadata "moov" described in the  
             ISOBMFF base media file format <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a></p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="moof"><strong>moof</strong></dfn>:
             the movie fragment "moof" box as described in the  
             ISOBMFF  base media file format <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> that describes  
             the metadata of a fragment of media.</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="mdat" data-noexport id="mdat"> <strong>mdat</strong> </dfn>:
             the media data container "mdat" box contained in  
             an ISOBMFF <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a>, this box contains the  
            compressed media samples</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="mfra"><strong>mfra</strong></dfn>:
            the movie fragment random access "mfra" box defined in  
            the ISOBMFF <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> to signal random access samples  
            (these are samples that require no prior  
            or other samples for decoding) <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a>.</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="tfdt" data-noexport id="tfdt"> <strong>tfdt</strong> </dfn>:
            the TrackFragmentBaseMediaDecodeTimeBox box "tfdt"  
            in the base media file format <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> used  
            to signal the decode time of the media  
            fragment signalled in the <a data-link-type="dfn" href="#moof" id="ref-for-moof">moof</a> box.</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="basemediadecodetime" data-noexport id="basemediadecodetime"> <strong>basemediadecodetime</strong> </dfn>:
            decode time of first sample as signalled in the <a data-link-type="dfn" href="#tfdt" id="ref-for-tfdt">tfdt</a> box</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="mdhd" data-noexport id="mdhd"> <strong>mdhd</strong> </dfn>:
             The media header box "mdhd" as defined in <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a>,  
             this box contains information about the media such  
             as timescale, duration, language using ISO 639-2/T <a data-link-type="biblio" href="#biblio-iso-639-2">[iso-639-2]</a> codes <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a></p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="elng" data-noexport id="elng"> <strong>elng</strong> </dfn>:
             extended language box "elng" defined in <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> that  
             can override the language information</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="nmhd" data-noexport id="nmhd"> <strong>nmhd</strong> </dfn>:
             The null media header Box "nmhd" as defined in <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> to signal a track for which no specific  
             media header is defined, often used for metadata tracks</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="HTTP POST" data-noexport id="http-post"> <strong>HTTP POST</strong> </dfn>:
             Command used in the Hyper Text Transfer Protocol for  
             sending data from a source to a destination [[!RFC2626]</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="media fragment" data-noexport id="media-fragment"> <strong>media fragment</strong> </dfn> media fragment, combination of moof and mdat in 
             ISOBMFF structure</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="fragmentedMP4stream" data-noexport id="fragmentedmp4stream"> <strong>fragmentedMP4stream</strong> </dfn>:
             A <a data-link-type="dfn" href="#fragmentedmp4stream" id="ref-for-fragmentedmp4stream">fragmentedMP4stream</a> can be defined  
             using the IETF RFC 5234 ANB <a data-link-type="biblio" href="#biblio-rfc5234">[RFC5234]</a> as follows. <strong>fragmentedMP4stream</strong> =
             headerboxes fragments:
             headerboxes = <a data-link-type="dfn" href="#ftyp" id="ref-for-ftyp">ftyp</a> <a data-link-type="dfn" href="#moov" id="ref-for-moov">moov</a> fragments = X fragment  
             fragment = <a data-link-type="dfn" href="#moof" id="ref-for-moof①">Moof</a> <a data-link-type="dfn" href="#mdat" id="ref-for-mdat">Mdat</a></p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="POST_URL" data-noexport id="post_url"> <strong>POST_URL</strong> </dfn>:
             Target URL of a POST command in the HTTP protocol  
             for posting data from a source to a destination.</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-lt="TCP" data-noexport id="tcp"> <strong>TCP</strong> </dfn>:
            Transmission Control Protocol (TCP) as defined in <a data-link-type="biblio" href="#biblio-rfc793">[RFC793]</a></p>
   <h2 class="heading settled" data-level="4" id="workflow_and_use_cases"><span class="secno">4. </span><span class="content">Media Ingest Workflows</span><a class="self-link" href="#workflow_and_use_cases"></a></h2>
   <p>In this section we highlight two example workflows.
  Diagram 3 shows an example workflow of media ingest  
  with fmp4 ingest in a streaming workflow. The live media  
  is ingested into the media processing entity that performs  
  operations like on-the-fly encryption, content stitching  
  packaging and possibly other operations before  
  delivery of the final media presentation to the client.  
  This type of distributed media processing offloads  
  many functionalities from the ingest source.  
  As long as the stream originating from the media  
  source contains sufficient metadata, the media  
  processing entity can generate the media presentation  
  for streaming to clients or other derived media  
  presentations as needed by a client.</p>
   <p>Diagram 4 shows an alternative example with ingest
  to a content delivery network, or perhaps another  
  passive media entity such as a storage. In this case  
  the live media source posts the segments and the  
  manifests for the media presentation.  
  In this case, still fragmented MPEG-4 segments can be used,  
  but the ingest works slightly different.</p>
   <p>Practice has shown that the ingest schemes
  can be quite different for the two configurations  
  , and that combining them into a single protocol  
  will result in overhead such as sending  
  duplicate information in the manifest or  
  ISOBMFF moov box, and increased  
  signalling overhead for starting, closing  
  and resetting the <a data-link-type="dfn" href="#connection" id="ref-for-connection">connection</a>. Therefore,  
  the two procedures for media ingest in  
  such two common workflows are presented  
  as separate profiles in the next two sections.</p>
<pre class="highlight">Diagram 3: Streaming workflow with fragmented MPEG-4 ingest in profile 1

============       ==============      ==============
|| live   ||ingest ||  Media   || HLS  || Content  ||  HLS
|| media  ||====>>>||processing||===>>>|| Delivery ||==>>> Client
|| source || fmp4  || entity   || DASH || Network  ||  DASH
============       ==============      ==============
</pre>
<pre class="highlight">Diagram 4:
Streaming workflow with DASH ingest in profile 2
============ingest ==============      
|| live   || DASH  || Content  ||   
|| media  ||====>>>||Delivery  ||==>>>> Client
|| source ||       || Network  ||  
============       ==============   
</pre>
   <p>In Diagram 5 we highlight some of the key
  differences for practical consideration between  
  the profiles. In profile 1 the encoder can be  
  simple as the media processing entity can  
  do many of the operations related to the  
  delivery such as encryption or generating the streaming  
  manifests. In addition the distribution of functionalities  
  can make it easier to scale a deployment with many  
  live media sources and media processing entities.</p>
   <p>In some cases, an encoder has sufficient
  capabilities to prepare the final presentation for the  
  client, in that case content can be ingested directly  
  to a more passive media processing entity that provides  
  a more pass through like functionality.  
  In this case also manifests and other client specific  
  information needs to be ingested. Besides these factors  
  , chosing a workflow for a video streaming platform depends  
  on many factors. The media ingest best practice  
  covers these two types of workflows by two different  
  profiles. The best choice for a specific platform depends  
  on many of the use case specific requirements, circumstances  
  and the available technologies.</p>
<pre class="highlight">  Diagram 5: Differences profile 1 and profile 2 for use cases
============================================================
|Profile   |    Ingest source     |   Media processing     |
|----------|----------------------|------------------------|
|Profile 1 |limited overview      |encrypt, transcode,     |
|          | simple encoder       |package, watermark      |
|          | multiple sources     |content stitch, timed   |
|Profile 2 |Global overview       | cache, store, deliver  |
|          |encoder targets client|                        |
|          |only duplicate sources| manifest manipulation  |
|          |                      | storage &amp; transmission |
============================================================
  
</pre>
<pre class="highlight">Diagram 6:
workflow with redundant Ingest sources and media processing entities

              fmp4  ==============     
============ stream||  Media   || 
|| Ingest ||====>>>||Processing|| \\
|| source ||   //  ||  Entity  ||  \\ 
============  //   ==============   \\  ============        
============ //                      \\ || load   || 
|| Ingest ||// redundant stream       >>||balancer|| ==>>> Client
|| source ||\\ stream                // =============
============ \\     =============   // 
============  \\   || Media     || //     
|| Ingest ||====>>>||Processing ||//        
|| source ||   //  || Entity    ||
============  //   ===============
============ //     
|| Ingest ||// redundant stream       
|| source ||       
============  
</pre>
   <p>In Diagram 6 we highlight another aspect taken into
  consideration for large scale systems with many users.  
  Often one would like to run multiple ingest sources,  
  multiple downstream processing entities and make them available  
  to the clients via a load balancer. This way requests  
  can be balanced over multiple processing nodes.  
  This approach is common when serving web pages,  
  and this architecture also applies to video  
  streaming platforms that also use <a data-link-type="biblio" href="#biblio-rfc7235">[RFC7235]</a>]. In Diagram  
   6 it is highlighted how one or more multiple live encoders can  
  be sending data to one or more processing entities. In  
  such a workflow it is important to handle the case  
  when one source or media processing entity fails over.  
  We call this support for failover. It is an important  
  consideration in practical video streaming systems that  
  need to run 24/7. Failovers must be handled robustly  
  and seamlesslessly without causing service interruption.  
  In both profiles we detail how this failover and redundancy  
  support can be achieved.</p>
   <h2 class="heading settled" data-level="5" id="general"><span class="secno">5. </span><span class="content">General Ingest Protocol Behavior</span><a class="self-link" href="#general"></a></h2>
   <p>The media ingest follows the following
  general requirements for both target profiles.</p>
   <ol>
    <li data-md>
     <p>The live encoder or ingest source communicates to
the <a data-link-type="dfn" href="#publishing-point" id="ref-for-publishing-point">publishing point</a> /processing entity using the HTTP
POST method as defined in the HTTP protocol <a data-link-type="biblio" href="#biblio-rfc7235">[RFC7235]</a></p>
    <li data-md>
     <p>The media ingest source SHOULD use HTTP over TLS <a data-link-type="biblio" href="#biblio-rfc2818">[RFC2818]</a> to connect to the media processing entity</p>
    <li data-md>
     <p>The ingest source SHOULD repeatedly resolve
the Hostname to adapt to changes in the IP to Hostname mapping
such as for example by using the dynamic naming system
DNS <a data-link-type="biblio" href="#biblio-rfc1035">[RFC1035]</a> or any other system that is in place.</p>
    <li data-md>
     <p>The ingest source MUST update the IP to hostname
resolution respecting the TTL (time to live) from DNS
query responses, this will enable better resillience
to changes of the IP address in large scale deployments
where the IP adress of the publishing point media
processing nodes may change frequenty.</p>
    <li data-md>
     <p>In case HTTPS <a data-link-type="biblio" href="#biblio-rfc2818">[RFC2818]</a> protocol is used,
basic authentication HTTP AUTH <a data-link-type="biblio" href="#biblio-rfc7617">[RFC7617]</a> or better methods like TLS client certificates SHOULD be used</p>
    <li data-md>
     <p>As compatibility profile for the TLS encryption
we recommend the ingest SHOULD use the mozzilla
intermediate compatibility profile which is supported
in many available implementations <a data-link-type="dfn" href="#mozillatls" id="ref-for-mozillatls">MozillaTLS</a>.</p>
    <li data-md>
     <p>The encoder or ingest source SHOULD terminate
the <a data-link-type="dfn" href="#http-post" id="ref-for-http-post">HTTP POST</a> request if data is not being sent
at a rate commensurate with the MP4 segment duration.
An HTTP POST request that does not send data can
prevent publishing points or media processing entities
from quickly disconnecting from the live encoder or
media ingest source in the event of a service update.
For this reason, the HTTP POST for sparse
data such as sparse tracks SHOULD be short-lived,
terminating as soon as the sparse fragment is sent.</p>
    <li data-md>
     <p>The POST request uses a POST_URL to the basepath of the
publishing point at the media processing entity and
MAY use a relative path for different streams and segments.</p>
   </ol>
   <h2 class="heading settled" data-level="6" id="profile_1_general"><span class="secno">6. </span><span class="content">Profile 1: Fragmented MPEG-4 Ingest General Considerations</span><a class="self-link" href="#profile_1_general"></a></h2>
   <p>The first profile assumes ingest to an active media processing entity,
from one or more <a data-link-type="dfn" href="#ingest-source" id="ref-for-ingest-source">ingest source</a>, ingesting one or more  
types of media streams. This advances over the ingest  
part of the smooth ingest protocol <a data-link-type="dfn" href="#ms-sstr" id="ref-for-ms-sstr②">MS-SSTR</a> by using  
standardized media container formats based on <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a>.  
In addition this allows extension to codecs like <a data-link-type="biblio" href="#biblio-mpeghevc">[MPEGHEVC]</a> and  
timed metadata ingest of subtitle and timed text streams.  
The workflow ingesting multiple media ingest streams with  
fragmented MPEG-4 ingest is illustrated in Diagram 7. Discussions
on the early development have been documented <a data-link-type="dfn" href="#fmp4git" id="ref-for-fmp4git">fmp4git</a>.</p>
<pre class="highlight"> Diagram 7: fragmented MPEG-4 ingest with multiple ingest sources

============ fmp4  ==============     
||        || video ||          || 
|| ingest ||====>>>||          ||
|| source ||       ||          || 
============       ||          ||      
||        || fmp4  ||          ||
|| ingest ||====>>>||  Active  ||      ==============
|| source || audio ||   Media  || HLS  || Content  ||  HLS
============       || procesing||===>>>|| Delivery ||==>>> Client
||        || fmp4  ||  entity  || DASH || Network  ||  DASH
||ingest  ||====>>>||          ||       =============
|| source || text  ||          ||
============       ||          ||
||        || fmp4  ||          || 
||ingest  || meta  ||          ||
|| source ||  data ||          ||
||        ||====>>>||          ||
============       ==============
</pre>
   <p>In diagrams 8-10 we detail some of the concepts and structures.
Diagram 8 shows the data format structure of fragmented   
MPEG-4 <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> and <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a>. In this format media meta data   
(playback time, sample duration) and sample data (encoded samples)   
are interleaved. the <a data-link-type="dfn" href="#moof" id="ref-for-moof②">moof</a> box as specified in <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> is used   
to signal the information to playback and decode the samples   
stored in the following mdat box.   
The <a data-link-type="dfn" href="#ftyp" id="ref-for-ftyp①">ftyp</a> and moov box contain the track specific information   
and can be seen as a header of the stream, sometimes referred   
as a <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> header. The styp box can be used to signal the   
type of segment. The combination of styp <a data-link-type="dfn" href="#moof" id="ref-for-moof③">moof</a> <a data-link-type="dfn" href="#mdat" id="ref-for-mdat①">mdat</a> can be referred   
as a segment, the combination of <a data-link-type="dfn" href="#ftyp" id="ref-for-ftyp②">ftyp</a> and <a data-link-type="dfn" href="#moof" id="ref-for-moof④">moof</a> can be referred   
to as an init segment or a CMAF header.</p>
<pre class="highlight">Diagram 8: fragmented mp4 stream: 

=========================================================
||ftyp||moov||styp||moof||mdat||styp||moof||mdat|| .....=
=========================================================
</pre>
   <p>Diagram 9 illustrates the synchronisation model, that
is in many ways similar, but simplified, from the synchronisation  
model propose in <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a>. Different bit-rate tracks  
and or media streams are conveyed in separate fragmented mp4 streams.  
by having the boundaries to the segments time alligned for tracks  
comprising the same stream at different bit-rates, bit-rate  
switching can be achieved. By using a common timeline  
different streams can be synchronized at the receiver,  
while they are in a separated fragmented mp4 stream  
send over a separate connection, possibly from a different <a data-link-type="dfn" href="#ingest-source" id="ref-for-ingest-source①">Ingest source</a>. for more information on the synchronisation
model we refer to section 6 of <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a>.</p>
   <p>In diagram 10 another advantage of this synchronisation model
is illustrated, the concept of late binding. In the case   
of late binding a new stream becomes available. By using   
the segment boundaries and a common timeline it can   
be received by the [
processing entity=] and embedded   
in the presentation. Late binding is useful for many   
practical use cases when broadcasting television   
content with different types of media and 
metadata tracks originating from different sources.</p>
<pre class="highlight">Diagram 9: fmp4 stream synchronisation:

=========================================================
||ftyp||moov||styp||moof||mdat||styp||moof||mdat|| .....=
=========================================================
||ftyp||moov||styp||moof||mdat||styp||moof||mdat|| .....=
=========================================================
||ftyp||moov||styp||moof||mdat||styp||moof||mdat|| .....=
=========================================================
</pre>
<pre class="highlight">Diagram 10: fmp4 late binding: 

===================================================
||ftyp||moov||styp||moof||mdat||moof||mdat|| .....=
===================================================
===================================================
||ftyp||moov||styp||moof||mdat||moof||mdat|| .....=
===================================================                   
</pre>
   <p>Diagram 11 shows the flow of the media ingest. It starts with a
DNS resolution (if needed) and an authentication step (Authy,   
TLS certificate) to establish a secure <a data-link-type="dfn" href="#tcp" id="ref-for-tcp">TCP</a> connection.   
In some private datacenter deployments where nodes   
are not reachable from outside, a non authenticated connection   
MAY also be used. The ingest source then issues a POST   
to test that the <a data-link-type="dfn" href="#media-processing-entity" id="ref-for-media-processing-entity">media processing entity</a> is listening. This 
POST contains the <a data-link-type="dfn" href="#moov" id="ref-for-moov①">moov</a> + <a data-link-type="dfn" href="#ftyp" id="ref-for-ftyp③">ftyp</a> box (the init segment).
In case this is succesfull this is followed by the rest of 
the segments in the fragmented MPEG-4 stream. In the end of 
the session, for tear down the source can send an empty <a data-link-type="dfn" href="#mfra" id="ref-for-mfra">mfra</a> box to close the connection.</p>
<pre class="highlight">Diagram 11: fmp4 ingest flow
||===============================================================||
||=====================            ============================  ||
||| live ingest source |            |  Media processing entity | ||
||=====================            ============================  ||
||        || &lt;&lt;------  DNS Resolve    -------->> ||              ||
||        || &lt;&lt;------  Authenticate   -------->> ||              ||
||        || &lt;&lt;------POST fmp4stream  -------->> ||              ||
||================== Moov + ftyp Sending  =======================||
||        || &lt;&lt;------ 404 Bad Request -----------||              ||
||        || &lt;&lt;------ 202 OK --------------------||              ||
||        || &lt;&lt;------ 403 Forbidden -------------||              ||
||        || &lt;&lt;------ 404 Bad Request            ||              ||
||        || &lt;&lt;------ 400 Forbidden -------------||              ||
||        ||         Unsupported Media Type      ||              ||
||        || &lt;&lt;------ 415 Forbidden -------------||              ||
||================== Moov + ftyp Sending  =======================||
||        || &lt;&lt;------ 202 OK --------------------||              ||
||============= fragmented MP4 Sending ==========================||
||        || &lt;&lt;------ 404 Bad Request -----------||              ||
||============= mfra box Sending (close) ========================||
||        || &lt;&lt;------ 200 OK --------------------||              ||
||=====================            ============================  ||
||| live ingest source |            |  Media processing entity | ||
||=====================            ============================  ||
||        ||                                     ||              ||
||===============================================================||
</pre>
   <h2 class="heading settled" data-level="7" id="profile_1"><span class="secno">7. </span><span class="content">Profile 1: Fragmented MPEG-4 Ingest Protocol Behavior #</span><a class="self-link" href="#profile_1"></a></h2>
   <p>This section describes the protocol behavior specific to
profile 1: fragmented MPEG-4 ingest. Operation of this  
profile MUST also adhere to general requirements in secion 4.</p>
   <h3 class="heading settled" data-level="7.1" id="general_Protocol_Requirements_p1"><span class="secno">7.1. </span><span class="content">General Protocol Requirements</span><a class="self-link" href="#general_Protocol_Requirements_p1"></a></h3>
   <ol>
    <li data-md>
     <p>The live encoder or ingest source SHOULD start
by sending an HTTP POST request with the 
init segment by using the POSTURL
This can help the live encoder or media
ingest source to quickly detect whether the
live ingest publishing point is valid,
and if there are any authentication
or other conditions required.</p>
    <li data-md>
     <p>The live encoder or ingest source MUST initiate
a media ingest connection by POSTING the
CMAF header boxes "ftyp" and "moov" after step 1</p>
    <li data-md>
     <p>The encoder or ingest source SHOULD use chunked transfer
encoding option of the HTTP POST command <a data-link-type="biblio" href="#biblio-rfc2626">[RFC2626]</a> as it might be difficult to predict the entire content length
of the segment. This can also be used for example to support
use cases that require low latency.</p>
    <li data-md>
     <p>If the HTTP POST request terminates or times out with a TCP
error prior to the end of the stream, the encoder MUST issue
a new connection, and follow the
preceding requirements. Additionally, the encoder MAY resend
the previous segment that was already sent again.</p>
    <li data-md>
     <p>The live encoder or ingest source MUST handle
any error or failed authentication responses
received from the media processing, by issueing
a new connection and following the preceding
requirements inlcluding retransmitting 
the ftyp and moov boxes of the CMAF track header.</p>
    <li data-md>
     <p>In case the <a data-link-type="dfn" href="#live-stream-event" id="ref-for-live-stream-event">live stream event</a> is over the
ingest source should signal
the stop by transmitting an empty [=mfra] box
towards the publishing point/processing entity.</p>
    <li data-md>
     <p>The <a data-link-type="dfn" href="#ingest-source" id="ref-for-ingest-source②">Ingest source</a> SHOULD use a separate TCP
connection for ingest of each different track</p>
    <li data-md>
     <p>The <a data-link-type="dfn" href="#ingest-source" id="ref-for-ingest-source③">Ingest source</a> MAY use a separate relative path
in the POST_URL for ingest of each different track by 
appending a relative path to the POST_URL</p>
    <li data-md>
     <p>The fragment decode timestamps <a data-link-type="dfn" href="#basemediadecodetime" id="ref-for-basemediadecodetime">basemediadecodetime</a> of fragments in the <a data-link-type="dfn" href="#fragmentedmp4stream" id="ref-for-fragmentedmp4stream①">fragmentedMP4stream</a> and the indexes base_media_decode_ time
SHOULD arrive in increasing order for each of the different
tracks/streams that are ingested.</p>
    <li data-md>
     <p>The fragment sequence numbers of fragments in the <a data-link-type="dfn" href="#fragmentedmp4stream" id="ref-for-fragmentedmp4stream②">fragmentedMP4stream</a> signalled in the tfhd
SHOULD arrive in increasing order for each of the different
tracks/streams that are ingested.</p>
    <li data-md>
     <p>Stream names MAY be signalled by adding the relative path
 Streams(stream_name) to the POST_URL</p>
    <li data-md>
     <p>The average and maximum bitrate of each track SHOULD be signalled
 in the btrt box in the sampleentry of the CMAF header</p>
   </ol>
   <h3 class="heading settled" data-level="7.2" id="Requirements_for_formatting_Media_Tracks"><span class="secno">7.2. </span><span class="content">Requirements for formatting Media Tracks</span><a class="self-link" href="#Requirements_for_formatting_Media_Tracks"></a></h3>
   <ol>
    <li data-md>
     <p>Media tracks SHALL be formatted using boxes
according to section 7 of [!MPEGCMAF]] except 
for section 7.4. which dictates boxes that are 
not compliant to <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a></p>
    <li data-md>
     <p>The trackFragmentDecodeTime box <a data-link-type="dfn" href="#tfdt" id="ref-for-tfdt①">tfdt</a> box
MUST be present for each segment posted.</p>
    <li data-md>
     <p>The ISOBMFF media fragment duration SHOULD be constant,
the duration MAY fluctuate to compensate
for non-integer frame rates. By choosing an appropriate
timescale (a multiple of the frame rate is recommended)
this issue SHOULD be avoided.</p>
    <li data-md>
     <p>The MPEG-4 fragment durations SHOULD be between
approximately 1 and 6 seconds.</p>
    <li data-md>
     <p>The segments formatted as fragmented MP4 stream SHOULD use
a timescale for video streams based on the framerate
and 44.1 KHz or 48 KHz for audio streams
or any another timescale that enables integer
increments of the decode times of
fragments signalled in the "tfdt" box based on this scale.
If necessary integer multiples of these timescales 
could be considered.</p>
    <li data-md>
     <p>The language of the stream SHOULD be signalled in the <a data-link-type="dfn" href="#mdhd" id="ref-for-mdhd">mdhd</a> box or <a data-link-type="dfn" href="#elng" id="ref-for-elng">elng</a> boxes in the
init segment and/or <a data-link-type="dfn" href="#moof" id="ref-for-moof⑤">moof</a> headers (<a data-link-type="dfn" href="#mdhd" id="ref-for-mdhd①">mdhd</a>).</p>
    <li data-md>
     <p>Segments posted towards the media procesing entity SHOULD
contain the bitrate "btrt" box specifying the target
average and maximum bitrate of the segments 
in the sample entry container in the init segment/CMAF header</p>
    <li data-md>
     <p>The media track MAY use the notion of a CMAF chunk <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> which is a moof mdat structure that may  
not be an IDR or switching point and is not targetted 
as an independently adressable media fragment</p>
    <li data-md>
     <p>For video tracks, profiles like avc1 and hvc1 MAY be used
that signal the sequence parameter set in the CMAF Header 
in the sample entry. In this case parameters do not change
dynamically during the live event and are signalled 
in the moviebox.</p>
    <li data-md>
     <p>Alternatively videotracks MAY use profiles like avc3 or
 hev1 that signal the parameter sets (PPS, SPS, VPS) in 
 band in the media samples in the mdat box.</p>
   </ol>
   <p class="note" role="note"><span>Note:</span> <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> has the notion of a segment, a fragment and a chunk.
A fragment can be composed of one or more chunks, while a segment can be 
composed of one or more fragments. The <a data-link-type="dfn" href="#media-fragment" id="ref-for-media-fragment">media fragment</a> defined here 
is independent of this notion and can be a chunk, a fragment containing 
a single chunk or a segment containing a single fragment containing 
a single chunk. Alternatively signalling may be defined for the 
fragment, segment chunk structure.</p>
   <h3 class="heading settled" data-level="7.3" id="timed_text_and_subtitle_streams"><span class="secno">7.3. </span><span class="content">Requirements for Timed Text Captions and Subtitle Streams</span><a class="self-link" href="#timed_text_and_subtitle_streams"></a></h3>
   <p>The media ingest follows the following requirements for ingesting
a track with timed text, captions and/or subtitle streams. The 
recommendations for formatting subtitle and timed text track 
are defined in <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> and <a data-link-type="biblio" href="#biblio-mpeg4-30">[MPEG4-30]</a> and are re-iterated 
here for convenience to the reader. Note the text in <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> references prevails the text below when different.</p>
   <ol>
    <li data-md>
     <p>The track will be a sparse track signalled by a null media
header <a data-link-type="dfn" href="#nmhd" id="ref-for-nmhd">nmhd</a> containing the timed text, images, captions
corresponding to the recommendation of storing tracks
in fragmented MPEG-4 <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a>, or a sthd for an ISOBMFF
subtitle track (e.g. TTML)</p>
    <li data-md>
     <p>Based on this recommendation the trackhandler "hdlr" shall
be set to "text" for WebVTT and "subt" for TTML following <a data-link-type="biblio" href="#biblio-mpeg4-30">[MPEG4-30]</a></p>
    <li data-md>
     <p>In case TTML is used the track must use the XMLSampleEntry
to signal sample description of the sub-title stream <a data-link-type="biblio" href="#biblio-mpeg4-30">[MPEG4-30]</a></p>
    <li data-md>
     <p>In case WebVTT is used the track must use the WVTTSampleEntry
to signal sample description of the text stream [[!MPEG4-30]</p>
    <li data-md>
     <p>These boxes SHOULD signal the mime type and specifics as
described in <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> sections 11.3 ,11.4 and 11.5</p>
    <li data-md>
     <p>The boxes described in 2-5 must be present in the init
segment (<a data-link-type="dfn" href="#ftyp" id="ref-for-ftyp④">ftyp</a> + <a data-link-type="dfn" href="#moov" id="ref-for-moov②">moov</a>) for the given track</p>
    <li data-md>
     <p>subtitles in CTA-608 and CTA-708 format SHOULD be conveyed
following the recommendation section 11.5 in <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> via
Supplemental Enhancement Information SEI messages
in the video track <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a></p>
    <li data-md>
     <p>The <a data-link-type="dfn" href="#ftyp" id="ref-for-ftyp⑤">ftyp</a> box in the init segment for the track
containing timed text, images, captions and sub-titles
MAY use signalling using CMAF profiles based on <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a></p>
     <p>8a. WebVTT   Specified in 11.2 ISO/IEC 14496-30 <a data-link-type="biblio" href="#biblio-mpeg4-30">[MPEG4-30]</a> <em>cwvt</em></p>
     <p>8b.TTML IMSC1 Text  Specified in 11.3.3 <a data-link-type="biblio" href="#biblio-mpeg4-30">[MPEG4-30]</a> IMSC1 Text Profile <em>im1t</em></p>
     <p>8c.TTML IMSC1 Image Specified in 11.3.4 <a data-link-type="biblio" href="#biblio-mpeg4-30">[MPEG4-30]</a> IMSC1 Image Profile <em>im1i</em></p>
     <p>8d. CEA  CTA-608 and CTA-708 Specified in 11.4 <a data-link-type="biblio" href="#biblio-mpeg4-30">[MPEG4-30]</a> Caption data is embedded in SEI messages in video track ccea</p>
    <li data-md>
     <p>The btrt SHOULD be used to signal the average and
  maximum bitrate in the sample entry box</p>
   </ol>
   <h3 class="heading settled" data-level="7.4" id="timed_metadata"><span class="secno">7.4. </span><span class="content">Requirements for Timed Metadata</span><a class="self-link" href="#timed_metadata"></a></h3>
   <p>This section discusses the specific formatting requirements
  for ingest of timed metadata related to events and markers for  
  ad insertion or other timed metadata  An example of  
  these are opportunities  for dynamic live ad insertion  
  signalled by SCTE-35 markers. This type of  event signalling  
  is different from regular audio/video information  
  because of its sparse nature. In this case,  
  the signalling data usually does not  
  happen continuously, and the intervals can  
  be hard to predict. Examples of timed metadata are ID3 tags <a data-link-type="biblio" href="#biblio-id3v2">[ID3v2]</a>, SCTE-35 markers <a data-link-type="biblio" href="#biblio-scte35">[SCTE35]</a> and DASH emsg  
  messages defined in section 5.10.3.3 of <a data-link-type="biblio" href="#biblio-mpegdash">[MPEGDASH]</a>. For example,  
  DASH Event messages contain a schemeIdUri that defines  
  the payload of the message.</p>
   <p>Table 1 provides some  example urn schemes
  Table 2  illustrates an example of a SCTE-35 marker stored  
  in a DASH emsg.  The presented approach allows ingest of  
  timed metadata from different sources,  
  possibly on different locations by embedding them in  
  sparse metadata tracks.</p>
   <p>Example messages include e-msg <a data-link-type="biblio" href="#biblio-mpegdash">[MPEGDASH]</a>, <a data-link-type="biblio" href="#biblio-dvb-dash">[DVB-DASH]</a>, <a data-link-type="biblio" href="#biblio-scte35">[SCTE35]</a> , <a data-link-type="biblio" href="#biblio-id3v2">[ID3v2]</a></p>
<pre class="highlight">Table 1 Example of DASH emsg schemes  URI
| Scheme URI                 | Reference                      | 
| --------------------------:|:------------------------------:| 
| urn:mpeg:dash:event:2012   | DASH, 5.10.4                   | 
| urn:dvb:iptv:cpm:2014      | DVB-DASH, 9.1.2.1              | 
|  urn:scte:scte35:2013:bin  | SCTE35] 14-3 (2015), 7.3.2     |  
| www.nielsen.com:id3:v1     | Nielsen ID3 in MPEG-DASH       |
</pre>
<pre class="highlight">Table 2 example of a SCTE-35 marker embedded in a DASH emsg  
| Tag                     |          Value                      |
|------------------------:|:-----------------------------------:|
| scheme_uri_id           | urn:scte:scte35:2013:bin            |
| Value                   | the value of the SCTE 35 PID        |
| Timescale               | positive number                     |
| presentation_time_delta | non-negative number, splice time    |
|                         | relative  to tfdt                   |
| event_duration          | duration of event  "0xFFFFFFFF"     |
|                         |  indicates unknown duration         |
| Id                      | unique identifier for message       |
| message_data            | splice info section including CRC   |
</pre>
   <p>The following steps are recommended for timed metadata
  ingest related to events, tags, ad markers and  
  program information:</p>
   <ol>
    <li data-md>
     <p>Create the metadata stream as a
fragmentedMP4stream that conveys the metadata
, the media handler (hdlr) is "meta",
the track handler box is a null media header box <a data-link-type="dfn" href="#nmhd" id="ref-for-nmhd①">nmhd</a>.</p>
    <li data-md>
     <p>The metadata stream applies to the media streams
in the presentation ingested to active publishing
point at the media processing entity</p>
    <li data-md>
     <p>The URIMetaSampleEntry entry contains, in a URIbox,
the URI following the URI syntax in <a data-link-type="biblio" href="#biblio-rfc3986">[RFC3986]</a> defining the form  of the metadata
(see the ISO Base media file format
 specification [[!ISOBMFF]). For example, the URIBox
 could contain for ID3 tags <a data-link-type="biblio" href="#biblio-id3v2">[ID3v2]</a> the URL  http://www.id3.org or
 or urn:scte:scte35:2013a:bin
 for scte 35 markers <a data-link-type="biblio" href="#biblio-scte35">[SCTE35]</a>}</p>
    <li data-md>
     <p>The timescale of the metadata should match the value
specified in the media header box "mdhd" of the
metadata track.</p>
    <li data-md>
     <p>The Arrival time is signalled in the "tfdt" box
of the track fragment  as the basemediadecode
time, this time when the metadata will be received</p>
    <li data-md>
     <p>The application time can be signalled as
a difference to the arrival time by having an 
empty sample with duration delta</p>
    <li data-md>
     <p>The duration of the sample signalled in the
trun box SHOULD correspond to the duration of 
the metadata</p>
    <li data-md>
     <p>Empty samples, and fragments with empty samples
SHOULD be used to fill the timeline</p>
    <li data-md>
     <p>All Timed Metadata samples SHOULD
be sync samples <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a>,
defining the entire set of
metadata for the time interval
they cover. Hence, the sync
sample table box SHOULD
not be present in the metadata stream.</p>
    <li data-md>
     <p>The metadata segment becomes available to the
publishing  point/ media processing entity
when the corresponding track fragment
from the media that has an equal
or larger timestamp compared to
the arrival time signalled
in the tfdt basemediadecodetime.
For example, if the sparse sample
has a timestamp of t=1000, it is expected that after the
publishing point/processing entity sees "video"
(assuming the parent track name is "video")
fragment timestamp 1000 or beyond, it can retrieve the
sparse fragment from the binary payload.</p>
    <li data-md>
     <p>The payload is conveyed
in the mdat box as sample information. This enables
muxing of the metadata tracks. For example
XML metadata can for example be coded as base64 as
common for <a data-link-type="biblio" href="#biblio-scte35">[SCTE35]</a> metadata messages</p>
    <li data-md>
     <p>In some cases, the duration of the metadata may not
be known, in this case the sample duration could 
be set to zero and updated later when the timestamp 
of the next metadata fragment is received.</p>
   </ol>
   <h3 class="heading settled" data-level="7.5" id="failover"><span class="secno">7.5. </span><span class="content">Requirements for Media Processing Entity Failover</span><a class="self-link" href="#failover"></a></h3>
   <p>Given the nature of live streaming, good failover support is
  critical for ensuring the availability of the service.  
  Typically, media services are designed to handle various types  
  of failures, including network errors, server errors, and storage  
  issues. When used in conjunction with proper failover  
  logic from the live encoder side, highly reliable live streaming  
  setups can be build. In this section, we discuss requirements  
  for failover scenarios.</p>
   <p>The following steps are required for a live encoder or media
  ingest source to deal with a failing media processing entity.</p>
   <ol>
    <li data-md>
     <p>Use a timeout for establishing the
TCP connection. If an attempt to establish 
the connection takes longer abort the operation and try again.</p>
    <li data-md>
     <p>Resend track segments for which a
connection was terminated early</p>
    <li data-md>
     <p>We recommend that the encoder or ingest source
does NOT limit the number of retries to establish a
connection or resume streaming after a TCP error occurs.</p>
    <li data-md>
     <p>After a TCP error:
a. The current connection MUST be closed,
  and a new connection MUST be created
  for a new HTTP POST request.
b. The new HTTP POST URL MUST be the same
  as the initial POST URL for the
  segment to be ingested.
c. The new HTTP POST MUST include stream
  headers (<a data-link-type="dfn" href="#ftyp" id="ref-for-ftyp⑥">ftyp</a>, and <a data-link-type="dfn" href="#moov" id="ref-for-moov③">moov</a> boxes)
  identical to the stream headers in the
  initial POST request for fragmented media ingest.</p>
    <li data-md>
     <p>In case the media processing entity cannot process the
  POST request due to authentication or permission
  problems then it SHOULD return a permission denied HTTP 403</p>
    <li data-md>
     <p>In case the media processing entity can process the request
  it SHOULD return an HTTP 200 OK or 202 Accepted</p>
    <li data-md>
     <p>In case the media processing entity can process
 the manifest or segment in the POST request body but finds
 the media type cannot be supported it SHOULD return an HTTP 415
 unsupported media type</p>
    <li data-md>
     <p>In case an unknown error happened during
 the processing of the HTTP
 POST request a HTTP 404 Bad request SHOULD be returned</p>
    <li data-md>
     <p>In case the media processing entity cannot
 proces a segment posted
 due to missing or incorrect init segment, an HTTP 412
 unfulfilled condition SHOULD be returned</p>
    <li data-md>
     <p>In case a media source receives an HTTP 412 response,
 it SHOULD resend <a data-link-type="dfn" href="#ftyp" id="ref-for-ftyp⑦">ftyp</a> and <a data-link-type="dfn" href="#moov" id="ref-for-moov④">moov</a> boxes</p>
   </ol>
   <h3 class="heading settled" data-level="7.6" id="failover_source"><span class="secno">7.6. </span><span class="content">Requirements for Live Media Source Failover</span><a class="self-link" href="#failover_source"></a></h3>
   <p>Live encoder or media ingest source failover is the second type
  of failover scenario that needs to be addressed for end-to-end  
  live streaming delivery. In this scenario, the error condition  
  occurs on the encoder side. The following expectations apply  
  to the live ingestion endpoint when encoder failover happens:</p>
   <ol>
    <li data-md>
     <p>A ingest source instance SHOULD be instantiated
  to continue streaming</p>
    <li data-md>
     <p>The ingest source MUST use
the same URL for HTTP POST requests as the failed instance.</p>
    <li data-md>
     <p>The new encoder or media ingest source POST request
  MUST include the same cmaf header box moov
  and <a data-link-type="dfn" href="#ftyp" id="ref-for-ftyp⑧">ftyp</a> as the failed instance</p>
    <li data-md>
     <p>The new encoder or media ingest source
  MUST be properly synced with all other running encoders
  for the same live presentation to generate synced audio/video  
  samples with aligned fragment boundaries.
  This implies that UTC timestamps
  for fragments in the "tfdt" match between decoders,
  and encoders start running at
  an appropriate segment boundaries.</p>
    <li data-md>
     <p>The new stream MUST be semantically equivalent
   with the previous stream, and interchangeable
   at the header and media fragment levels.</p>
    <li data-md>
     <p>The new encoder or media ingest source SHOULD
  try to minimize data loss. The basemediadecodetime tdft
  of media fragments SHOULD increase from the point where
  the encoder last stopped. The basemediadecodetime in the
  tdft box SHOULD increase in a continuous manner, but it
  is permissible to introduce a discontinuity, if necessary.
  Media processing entities or publishing points can ignore
  fragments that it has already received and processed, so
  it is better to error on the side of resending fragments
  than to introduce discontinuities in the media timeline.</p>
   </ol>
   <h2 class="heading settled" data-level="8" id="dash_ingest"><span class="secno">8. </span><span class="content">Profile 2: DASH and HLS Ingest General Considerations</span><a class="self-link" href="#dash_ingest"></a></h2>
   <p>Profile 2 is designed to ingest media into entities that only
   provide pass through functionality. In this case the media  
   ingest source also provides the manifest based on MPEG DASH <a data-link-type="biblio" href="#biblio-mpegdash">[MPEGDASH]</a> or HTTP Live Streaming <a data-link-type="biblio" href="#biblio-rfc8216">[RFC8216]</a>.</p>
   <p>The key idea here is to reuse the fragmented MPEG-4 ingest to
   enable simulatneous ingest of DASH <a data-link-type="biblio" href="#biblio-mpegdash">[MPEGDASH]</a> and HLS <a data-link-type="biblio" href="#biblio-rfc8216">[RFC8216]</a> based on the  
   fragmented MPEG-4 files using commonalities as  
   described in <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a> which is a format based on fragmented  
   MPEG-4 that can be used in both DASH and HLS presentations.</p>
   <p>The flow of operation in profile 2 is shown in Diagram 12. In this
   case the <a data-link-type="dfn" href="#ingest-source" id="ref-for-ingest-source④">Ingest source</a> (media source) sends a manifest first.  
   Based on this manifest the media processing entity can setup  
   reception paths for the ingest url  
   http://hostname/presentationpath  
   In the next step segments are send in individual post requests  
   using URLS corresponding to relative  
   paths and segment names in the manifest.  
   e.g. http://hostname/presentationpath/relative_path/segment1.cmf</p>
   <p>This profile re-uses as much functionality as possible from
   profile  1 as the manifest can be seen  
   as a complementary addition to the  
   fragmented MPEG-4 stream. A difference lies in the way  
   the connection is setup and the way data is transmitted,  
   which can use relative URL paths for the segments based on the  
   paths in the manifest. For the rest, it largely  
   uses the same fragmented MPEG-4 layer based on <a data-link-type="biblio" href="#biblio-isobmff">[ISOBMFF]</a> and <a data-link-type="biblio" href="#biblio-mpegcmaf">[MPEGCMAF]</a>.</p>
<pre class="highlight">Diagram 12
||===============================================================|| 
||=====================            ============================  || 
||| live media source |            |  Media processing entity |  ||
||=====================            ============================  ||
||        ||                                     ||              ||
||===============Initial Manifest Sending========================||
||        ||                                     ||              ||
||        ||-- POST /prefix/media.mpd  -------->>||              ||
||        ||          Succes                     ||              ||
||        || &lt;&lt;------ 200 OK --------------------||              ||
||        ||      Permission denied              ||              ||
||        || &lt;&lt;------ 403 Forbidden -------------||              ||
||        ||             Bad Request             ||              ||
||        || &lt;&lt;------ 400 Forbidden -------------||              ||
||        ||         Unsupported Media Type      ||              ||
||        || &lt;&lt;-- 412 Unfulfilled Condition -----||              ||
||        ||         Unsupported Media Type      ||              ||
||        || &lt;&lt;------ 415 Unsupported Media -----||              ||
||        ||                                     ||              ||
||==================== Segment Sending ==========================|| 
||        ||-- POST /prefix/chunk.cmaf  ------->>||              ||
||        ||          Succes/Accepted            ||              ||
||        || &lt;&lt;------ 200 OK --------------------||              ||
||        ||          Succes/Accepted            ||              ||
||        || &lt;&lt;------ 202 OK --------------------||              ||
||        ||      Premission Denied              ||              ||
||        || &lt;&lt;------ 403 Forbidden -------------||              ||
||        ||             Bad Request             ||              ||
||        || &lt;&lt;------ 400 Forbidden -------------||              ||
||        ||         Unsupported Media Type      ||              ||
||        || &lt;&lt;------ 415 Forbidden -------------||              ||
||        ||         Unsupported Media Type      ||              ||
||        || &lt;&lt;-- 412 Unfulfilled Condition -----||              ||
||        ||                                     ||              ||
||        ||                                     ||              ||
||=====================            ============================  || 
||| live media source |            |  Media processing entity |  ||
||=====================            ============================  ||
||        ||                                     ||              ||
||===============================================================|| 
</pre>
   <h2 class="heading settled" data-level="9" id="Dash_ingest_behavior"><span class="secno">9. </span><span class="content">profile 2: DASH Ingest Protocol Behavior</span><a class="self-link" href="#Dash_ingest_behavior"></a></h2>
   <p>Operation of this profile MUST also adhere
to general requirements in section 5.</p>
   <h3 class="heading settled" data-level="9.1" id="Dash_ingest_behavior_reqs"><span class="secno">9.1. </span><span class="content">General Protocol Requirements</span><a class="self-link" href="#Dash_ingest_behavior_reqs"></a></h3>
   <ol>
    <li data-md>
     <p>Ingest source
MUST send a manifest <a data-link-type="biblio" href="#biblio-mpegdash">[MPEGDASH]</a> with the following the limitations/constraints.
1a. Only relative URL paths to be used for each segment
1b. Only unique paths are used for each new presentation
1c. In case the manifest contains these relative paths,
these paths SHOULD be used in combination with the <a data-link-type="dfn" href="#post_url" id="ref-for-post_url">POST_URL</a> to HTTP POST each of the different segments from
the live encoder or ingest source
to the processing entity.</p>
    <li data-md>
     <p>The live encoder or ingest source MAY send
updated versions of the manifest,
this manifest cannot override current
settings and relative paths or break currently running and
incoming POST requests. The updated manifest can only be
slightly different from the one that was send previously,
e.g. introduce new segments available or event messages.
The updated manifest SHOULD be send using a PUT request
instead of a POST request.</p>
    <li data-md>
     <p>Following media segment requests <a data-link-type="dfn" href="#post_url" id="ref-for-post_url①">POST_URL</a>s SHOULD be corresponding to the segments listed
in the manifest as POST_URL + relative URLs.</p>
    <li data-md>
     <p>The encoder or ingest source SHOULD use
individual HTTP POST commands <a data-link-type="biblio" href="#biblio-rfc2626">[RFC2626]</a> for uploading media segments when available.</p>
    <li data-md>
     <p>In case fixed length POST Commands are used, the live source
entity MUST resend the segment to be posted decribed
in the manifest entirely in case of responses HTTP 400, 404
412 or 415 together with the init segment consisting
of "moov" and "ftyp" boxes</p>
    <li data-md>
     <p>A persistent connection SHOULD be used for the different
individual POST requests as defined in <a data-link-type="biblio" href="#biblio-rfc2626">[RFC2626]</a> enabling
re-use of the TCP connection for multiple POST requests.</p>
    <li data-md>
     <p>Each of fragment posted corresponds to a unique
name+directory+timestamp</p>
    <li data-md>
     <p>When the content lenght is known short formed POST SHOULD
be used instead of a chunked transfer</p>
   </ol>
   <h3 class="heading settled" data-level="9.2" id="Dash_ingest_behavior_media_track"><span class="secno">9.2. </span><span class="content">Requirements for Formatting Media Tracks</span><a class="self-link" href="#Dash_ingest_behavior_media_track"></a></h3>
   <ol>
    <li data-md>
     <p>Media data tracks will be uploaded by individual segments, that
use file extensions (.cmfv, .cfma etc.) to signal the type of content 
in the segment</p>
    <li data-md>
     <p>Media specific information SHOULD be signalled in the manifest</p>
    <li data-md>
     <p>Formatting described in manifest and media track MUST
correspond consistently</p>
   </ol>
   <h3 class="heading settled" data-level="9.3" id="Dash_ingest_behavior_text_track"><span class="secno">9.3. </span><span class="content">Requirements for Timed Text Captions and Subtitle stream</span><a class="self-link" href="#Dash_ingest_behavior_text_track"></a></h3>
   <ol>
    <li data-md>
     <p>Timed Text, caption and subtitle stream tracks  MUST
be formatted conforming to the same requirements as in 6.3</p>
    <li data-md>
     <p>Timed Text captions and subtitle specific information
SHOULD also be signalled in the manifest</p>
    <li data-md>
     <p>Formatting described in manifest and
media track MUST correspond consistently</p>
   </ol>
   <h3 class="heading settled" data-level="9.4" id="Dash_ingest_behavior_meta_track"><span class="secno">9.4. </span><span class="content">Requirements for Timed Metadata</span><a class="self-link" href="#Dash_ingest_behavior_meta_track"></a></h3>
   <ol>
    <li data-md>
     <p>timed metadata is signalled using the higher level representation (DASH/HLS)</p>
   </ol>
   <h3 class="heading settled" data-level="9.5" id="Dash_ingest_behavior_fail_track"><span class="secno">9.5. </span><span class="content">Requirements for Media Processing Entity Failover</span><a class="self-link" href="#Dash_ingest_behavior_fail_track"></a></h3>
   <ol>
    <li data-md>
     <p>To be defined, including response codes</p>
   </ol>
   <h3 class="heading settled" data-level="9.6" id="Dash_ingest_behavior_fail_source_track"><span class="secno">9.6. </span><span class="content">Requirements for Live Media Source Failover</span><a class="self-link" href="#Dash_ingest_behavior_fail_source_track"></a></h3>
   <ol>
    <li data-md>
     <p>To be defined</p>
   </ol>
   <h2 class="heading settled" data-level="10" id="security"><span class="secno">10. </span><span class="content">Security Considerations</span><a class="self-link" href="#security"></a></h2>
   <p>Security consideration are extremely important
   for media ingest. Retrieving media from a illicit  
   source can cause inappropriate content  
   to be broadcasted  
   and possibly lead to failure of infrastructure.  
   Basic security requirements have been covered in  
   section 5.  
   No security considerations except the ones mentioned  
   in this part of the text are expelictly considered.  
   Further security considerations will be updated  
   once they have been investigated further based  
   on review of this draft.</p>
   <h2 class="heading settled" data-level="11" id="iana"><span class="secno">11. </span><span class="content">IANA Considerations</span><a class="self-link" href="#iana"></a></h2>
   <p>This memo includes no request to IANA.</p>
   <h2 class="heading settled" data-level="12" id="contrib"><span class="secno">12. </span><span class="content">Contributors</span><a class="self-link" href="#contrib"></a></h2>
   <p>Will Law Akamai</p>
   <p>James Gruessing BBC R&amp;D</p>
   <p>Kevin Moore Amazon AWS Elemental</p>
   <p>Kevin Johns CenturyLink</p>
   <p>John Deutscher Microsoft</p>
   <p>Patrick Gendron Harmonic Inc.</p>
   <p>Nikos Kyriopoulos MediaExcel</p>
   <p>Rufael Mekuria Unified Streaming</p>
   <p>Sam Geqiang Zhang Microsoft</p>
   <p>Arjen Wagenaar Unified Streaming</p>
   <p>Dirk Griffioen Unified Streaming</p>
   <p>Matt Poole ITV</p>
   <p>Alex Giladi Comcast</p>
   <h2 class="heading settled" data-level="13" id="references_custom"><span class="secno">13. </span><span class="content">References</span><a class="self-link" href="#references_custom"></a></h2>
   <h3 class="heading settled" data-level="13.1" id="references-url"><span class="secno">13.1. </span><span class="content">URL References</span><a class="self-link" href="#references-url"></a></h3>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="fmp4git">fmp4git</dfn> Unified Streaming github fmp4 ingest,
                "https://github.com/unifiedstreaming/fmp4-ingest".</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="mozillatls">MozillaTLS</dfn> Mozilla Wikie Security/Server Side TLS
                https://wiki.mozilla.org/Security/Server_Side_TLS
                #Intermediate_compatibility_.28default.29
                (last acessed 30th of March 2018)</p>
   <p><dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="ms-sstr">MS-SSTR</dfn> Smooth streaming protocol
              https://msdn.microsoft.com/en-us/library/ff469518.aspx
                last updated March 16 2018 (last acessed June 11 2018)</p>
   <h2 class="heading settled" data-level="14" id="Authors"><span class="secno">14. </span><span class="content">Author’s Address</span><a class="self-link" href="#Authors"></a></h2>
   <p>Rufael Mekuria (editor)
   Unified Streaming  
   Overtoom 60 1054HK</p>
   <p>Phone: +31 (0)202338801
   E-Mail: rufael@unified-streaming.com</p>
   <p>Sam Geqiang Zhang
   Microsoft  
   E-mail: Geqiang.Zhang@microsoft.com</p>
  </main>
  <div data-fill-with="conformance">
   <h2 class="no-ref no-num heading settled" id="conformance"><span class="content"> Conformance</span><a class="self-link" href="#conformance"></a></h2>
   <p> Conformance requirements are expressed with a combination of descriptive assertions and RFC 2119 terminology.
            The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL”
            in the normative parts of this document
            are to be interpreted as described in RFC 2119.
            However, for readability,
            these words do not appear in all uppercase letters in this specification. </p>
   <p> All of the text of this specification is normative
            except sections explicitly marked as non-normative, examples, and notes. <a data-link-type="biblio" href="#biblio-rfc2119">[RFC2119]</a> </p>
   <p> Examples in this specification are introduced with the words “for example”
            or are set apart from the normative text with <code>class="example"</code>, like this: </p>
   <div class="example" id="example-example"><a class="self-link" href="#example-example"></a> This is an example of an informative example. </div>
   <p> Informative notes begin with the word “Note”
            and are set apart from the normative text with <code>class="note"</code>, like this: </p>
   <p class="note" role="note"> Note, this is an informative note. </p>
  </div>
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  <h2 class="no-num no-ref heading settled" id="index"><span class="content">Index</span><a class="self-link" href="#index"></a></h2>
  <h3 class="no-num no-ref heading settled" id="index-defined-here"><span class="content">Terms defined by this specification</span><a class="self-link" href="#index-defined-here"></a></h3>
  <ul class="index">
   <li><a href="#basemediadecodetime">basemediadecodetime</a><span>, in §3</span>
   <li><a href="#connection">Connection</a><span>, in §3</span>
   <li><a href="#elng">elng</a><span>, in §3</span>
   <li><a href="#fmp4git">fmp4git</a><span>, in §13.1</span>
   <li><a href="#fragmentedmp4stream">fragmentedMP4stream</a><span>, in §3</span>
   <li><a href="#ftyp">ftyp</a><span>, in §3</span>
   <li><a href="#http-post">HTTP POST</a><span>, in §3</span>
   <li><a href="#ingest-source">Ingest source</a><span>, in §3</span>
   <li><a href="#ingest-stream">Ingest Stream</a><span>, in §3</span>
   <li><a href="#live-stream-event">Live Stream Event</a><span>, in §3</span>
   <li><a href="#mdat">mdat</a><span>, in §3</span>
   <li><a href="#mdhd">mdhd</a><span>, in §3</span>
   <li><a href="#media-fragment">media fragment</a><span>, in §3</span>
   <li><a href="#media-processing-entity">Media processing entity</a><span>, in §3</span>
   <li><a href="#mfra">mfra</a><span>, in §3</span>
   <li><a href="#moof">moof</a><span>, in §3</span>
   <li><a href="#moov">moov</a><span>, in §3</span>
   <li><a href="#mozillatls">MozillaTLS</a><span>, in §13.1</span>
   <li><a href="#ms-sstr">MS-SSTR</a><span>, in §13.1</span>
   <li><a href="#nmhd">nmhd</a><span>, in §3</span>
   <li><a href="#post_url">POST_URL</a><span>, in §3</span>
   <li><a href="#publishing-point">Publishing point</a><span>, in §3</span>
   <li><a href="#tcp">TCP</a><span>, in §3</span>
   <li><a href="#tfdt">tfdt</a><span>, in §3</span>
  </ul>
  <h2 class="no-num no-ref heading settled" id="references"><span class="content">References</span><a class="self-link" href="#references"></a></h2>
  <h3 class="no-num no-ref heading settled" id="normative"><span class="content">Normative References</span><a class="self-link" href="#normative"></a></h3>
  <dl>
   <dt id="biblio-id3v2">[ID3v2]
   <dd><a href="http://id3.org/id3v2.4.0-structure">ID3 tag version 2.4.0 - Main Structure</a>. URL: <a href="http://id3.org/id3v2.4.0-structure">http://id3.org/id3v2.4.0-structure</a>
   <dt id="biblio-iso-639-2">[ISO-639-2]
   <dd>ISO/TC 37/SC 2. <a href="https://www.iso.org/standard/4767.html">Codes for the representation of names of languages -- Part 2: Alpha-3 code</a>. 1998. International Standard. URL: <a href="https://www.iso.org/standard/4767.html">https://www.iso.org/standard/4767.html</a>
   <dt id="biblio-isobmff">[ISOBMFF]
   <dd><a href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c068960_ISO_IEC_14496-12_2015.zip">Information technology — Coding of audio-visual objects — Part 12: ISO Base Media File Format</a>. December 2015. International Standard. URL: <a href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c068960_ISO_IEC_14496-12_2015.zip">http://standards.iso.org/ittf/PubliclyAvailableStandards/c068960_ISO_IEC_14496-12_2015.zip</a>
   <dt id="biblio-mpeg4-30">[MPEG4-30]
   <dd><a href="https://www.iso.org/standard/63107.html">ISO/IEC 14496-30:2014 Preview Information technology -- Coding of audio-visual objects -- Part 30: Timed text and other visual overlays in ISO base media file format</a>. March 2014. URL: <a href="https://www.iso.org/standard/63107.html">https://www.iso.org/standard/63107.html</a>
   <dt id="biblio-mpegcmaf">[MPEGCMAF]
   <dd><a href="https://www.iso.org/standard/71975.html">ISO/IEC 23000-19:2018 Information technology -- Multimedia application format (MPEG-A) -- Part 19: Common media application format (CMAF) for segmented media</a>. January 2018. URL: <a href="https://www.iso.org/standard/71975.html">https://www.iso.org/standard/71975.html</a>
   <dt id="biblio-mpegdash">[MPEGDASH]
   <dd><a href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip">ISO/IEC 23009-1:2014 Information technology -- Dynamic adaptive streaming over HTTP (DASH) -- Part 1: Media presentation description and segment formats</a>. URL: <a href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip">http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip</a>
   <dt id="biblio-mpeghevc">[MPEGHEVC]
   <dd><a href="https://www.iso.org/standard/35424.html">ISO/IEC 23008-2:2013 Information technology -- High efficiency coding and media delivery in heterogeneous environments -- Part 2: High efficiency video coding</a>. December 2013. URL: <a href="https://www.iso.org/standard/35424.html">https://www.iso.org/standard/35424.html</a>
   <dt id="biblio-rfc1035">[RFC1035]
   <dd>P.V. Mockapetris. <a href="https://tools.ietf.org/html/rfc1035">Domain names - implementation and specification</a>. November 1987. Internet Standard. URL: <a href="https://tools.ietf.org/html/rfc1035">https://tools.ietf.org/html/rfc1035</a>
   <dt id="biblio-rfc2119">[RFC2119]
   <dd>S. Bradner. <a href="https://tools.ietf.org/html/rfc2119">Key words for use in RFCs to Indicate Requirement Levels</a>. March 1997. Best Current Practice. URL: <a href="https://tools.ietf.org/html/rfc2119">https://tools.ietf.org/html/rfc2119</a>
   <dt id="biblio-rfc2626">[RFC2626]
   <dd>P. Nesser II. <a href="https://tools.ietf.org/html/rfc2626">The Internet and the Millennium Problem (Year 2000)</a>. June 1999. Informational. URL: <a href="https://tools.ietf.org/html/rfc2626">https://tools.ietf.org/html/rfc2626</a>
   <dt id="biblio-rfc2818">[RFC2818]
   <dd>E. Rescorla. <a href="https://tools.ietf.org/html/rfc2818">HTTP Over TLS</a>. May 2000. Informational. URL: <a href="https://tools.ietf.org/html/rfc2818">https://tools.ietf.org/html/rfc2818</a>
   <dt id="biblio-rfc3986">[RFC3986]
   <dd>T. Berners-Lee; R. Fielding; L. Masinter. <a href="https://tools.ietf.org/html/rfc3986">Uniform Resource Identifier (URI): Generic Syntax</a>. January 2005. Internet Standard. URL: <a href="https://tools.ietf.org/html/rfc3986">https://tools.ietf.org/html/rfc3986</a>
   <dt id="biblio-rfc5234">[RFC5234]
   <dd>D. Crocker, Ed.; P. Overell. <a href="https://tools.ietf.org/html/rfc5234">Augmented BNF for Syntax Specifications: ABNF</a>. January 2008. Internet Standard. URL: <a href="https://tools.ietf.org/html/rfc5234">https://tools.ietf.org/html/rfc5234</a>
   <dt id="biblio-rfc7235">[RFC7235]
   <dd>R. Fielding, Ed.; J. Reschke, Ed.. <a href="https://tools.ietf.org/html/rfc7235">Hypertext Transfer Protocol (HTTP/1.1): Authentication</a>. June 2014. Proposed Standard. URL: <a href="https://tools.ietf.org/html/rfc7235">https://tools.ietf.org/html/rfc7235</a>
   <dt id="biblio-rfc7617">[RFC7617]
   <dd>J. Reschke. <a href="https://tools.ietf.org/html/rfc7617">The 'Basic' HTTP Authentication Scheme</a>. September 2015. Proposed Standard. URL: <a href="https://tools.ietf.org/html/rfc7617">https://tools.ietf.org/html/rfc7617</a>
   <dt id="biblio-rfc793">[RFC793]
   <dd>J. Postel. <a href="https://tools.ietf.org/html/rfc793">Transmission Control Protocol</a>. September 1981. Internet Standard. URL: <a href="https://tools.ietf.org/html/rfc793">https://tools.ietf.org/html/rfc793</a>
   <dt id="biblio-rfc8216">[RFC8216]
   <dd>R. Pantos, Ed.; W. May. <a href="https://tools.ietf.org/html/rfc8216">HTTP Live Streaming</a>. August 2017. Informational. URL: <a href="https://tools.ietf.org/html/rfc8216">https://tools.ietf.org/html/rfc8216</a>
   <dt id="biblio-scte35">[SCTE35]
   <dd><a href="https://www.scte.org/SCTEDocs/Standards/SCTE%2035%202016.pdf">Digital Program Insertion Cueing Message for Cable</a>. URL: <a href="https://www.scte.org/SCTEDocs/Standards/SCTE%2035%202016.pdf">https://www.scte.org/SCTEDocs/Standards/SCTE%2035%202016.pdf</a>
  </dl>
  <h3 class="no-num no-ref heading settled" id="informative"><span class="content">Informative References</span><a class="self-link" href="#informative"></a></h3>
  <dl>
   <dt id="biblio-dvb-dash">[DVB-DASH]
   <dd><a href="http://www.etsi.org/deliver/etsi_ts/103200_103299/103285/01.02.01_60/ts_103285v010201p.pdf">ETSI TS 103 285 Digital Video Broadcasting (DVB); MPEG-DASH Profile for Transport of ISO BMFF Based DVB Services over IP Based Networks</a>. March 2018. URL: <a href="http://www.etsi.org/deliver/etsi_ts/103200_103299/103285/01.02.01_60/ts_103285v010201p.pdf">http://www.etsi.org/deliver/etsi_ts/103200_103299/103285/01.02.01_60/ts_103285v010201p.pdf</a>
  </dl>
  <aside class="dfn-panel" data-for="ingest-stream">
   <b><a href="#ingest-stream">#ingest-stream</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-ingest-stream">3. Conventions and Terminology</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="live-stream-event">
   <b><a href="#live-stream-event">#live-stream-event</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-live-stream-event">7.1. General Protocol Requirements</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="ingest-source">
   <b><a href="#ingest-source">#ingest-source</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-ingest-source">6. Profile 1: Fragmented MPEG-4 Ingest General Considerations</a> <a href="#ref-for-ingest-source①">(2)</a>
    <li><a href="#ref-for-ingest-source②">7.1. General Protocol Requirements</a> <a href="#ref-for-ingest-source③">(2)</a>
    <li><a href="#ref-for-ingest-source④">8. Profile 2: DASH and HLS Ingest General Considerations</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="publishing-point">
   <b><a href="#publishing-point">#publishing-point</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-publishing-point">5. General Ingest Protocol Behavior</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="media-processing-entity">
   <b><a href="#media-processing-entity">#media-processing-entity</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-media-processing-entity">6. Profile 1: Fragmented MPEG-4 Ingest General Considerations</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="connection">
   <b><a href="#connection">#connection</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-connection">4. Media Ingest Workflows</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="ftyp">
   <b><a href="#ftyp">#ftyp</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-ftyp">3. Conventions and Terminology</a>
    <li><a href="#ref-for-ftyp①">6. Profile 1: Fragmented MPEG-4 Ingest General Considerations</a> <a href="#ref-for-ftyp②">(2)</a> <a href="#ref-for-ftyp③">(3)</a>
    <li><a href="#ref-for-ftyp④">7.3. Requirements for Timed Text Captions and Subtitle Streams</a> <a href="#ref-for-ftyp⑤">(2)</a>
    <li><a href="#ref-for-ftyp⑥">7.5. Requirements for Media Processing Entity Failover</a> <a href="#ref-for-ftyp⑦">(2)</a>
    <li><a href="#ref-for-ftyp⑧">7.6. Requirements for Live Media Source Failover</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="moov">
   <b><a href="#moov">#moov</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-moov">3. Conventions and Terminology</a>
    <li><a href="#ref-for-moov①">6. Profile 1: Fragmented MPEG-4 Ingest General Considerations</a>
    <li><a href="#ref-for-moov②">7.3. Requirements for Timed Text Captions and Subtitle Streams</a>
    <li><a href="#ref-for-moov③">7.5. Requirements for Media Processing Entity Failover</a> <a href="#ref-for-moov④">(2)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="moof">
   <b><a href="#moof">#moof</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-moof">3. Conventions and Terminology</a> <a href="#ref-for-moof①">(2)</a>
    <li><a href="#ref-for-moof②">6. Profile 1: Fragmented MPEG-4 Ingest General Considerations</a> <a href="#ref-for-moof③">(2)</a> <a href="#ref-for-moof④">(3)</a>
    <li><a href="#ref-for-moof⑤">7.2. Requirements for formatting Media Tracks</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="mdat">
   <b><a href="#mdat">#mdat</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-mdat">3. Conventions and Terminology</a>
    <li><a href="#ref-for-mdat①">6. Profile 1: Fragmented MPEG-4 Ingest General Considerations</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="mfra">
   <b><a href="#mfra">#mfra</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-mfra">6. Profile 1: Fragmented MPEG-4 Ingest General Considerations</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="tfdt">
   <b><a href="#tfdt">#tfdt</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-tfdt">3. Conventions and Terminology</a>
    <li><a href="#ref-for-tfdt①">7.2. Requirements for formatting Media Tracks</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="basemediadecodetime">
   <b><a href="#basemediadecodetime">#basemediadecodetime</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-basemediadecodetime">7.1. General Protocol Requirements</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="mdhd">
   <b><a href="#mdhd">#mdhd</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-mdhd">7.2. Requirements for formatting Media Tracks</a> <a href="#ref-for-mdhd①">(2)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="elng">
   <b><a href="#elng">#elng</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-elng">7.2. Requirements for formatting Media Tracks</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="nmhd">
   <b><a href="#nmhd">#nmhd</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-nmhd">7.3. Requirements for Timed Text Captions and Subtitle Streams</a>
    <li><a href="#ref-for-nmhd①">7.4. Requirements for Timed Metadata</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="http-post">
   <b><a href="#http-post">#http-post</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-http-post">5. General Ingest Protocol Behavior</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="media-fragment">
   <b><a href="#media-fragment">#media-fragment</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-media-fragment">7.2. Requirements for formatting Media Tracks</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="fragmentedmp4stream">
   <b><a href="#fragmentedmp4stream">#fragmentedmp4stream</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-fragmentedmp4stream">3. Conventions and Terminology</a>
    <li><a href="#ref-for-fragmentedmp4stream①">7.1. General Protocol Requirements</a> <a href="#ref-for-fragmentedmp4stream②">(2)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="post_url">
   <b><a href="#post_url">#post_url</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-post_url">9.1. General Protocol Requirements</a> <a href="#ref-for-post_url①">(2)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="tcp">
   <b><a href="#tcp">#tcp</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-tcp">6. Profile 1: Fragmented MPEG-4 Ingest General Considerations</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="fmp4git">
   <b><a href="#fmp4git">#fmp4git</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-fmp4git">6. Profile 1: Fragmented MPEG-4 Ingest General Considerations</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="mozillatls">
   <b><a href="#mozillatls">#mozillatls</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-mozillatls">5. General Ingest Protocol Behavior</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="ms-sstr">
   <b><a href="#ms-sstr">#ms-sstr</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-ms-sstr">2. Introduction</a> <a href="#ref-for-ms-sstr①">(2)</a>
    <li><a href="#ref-for-ms-sstr②">6. Profile 1: Fragmented MPEG-4 Ingest General Considerations</a>
   </ul>
  </aside>
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            hitALink = true;
        }
        if(el.classList.contains("dfn-paneled")) {
            target = "dfn";
            break;
        }
        if(el.classList.contains("dfn-panel")) {
            target = "dfn-panel";
            break;
        }
        el = el.parentElement;
    }
    if(target != "dfn-panel") {
        // Turn off any currently "on" or "activated" panels.
        queryAll(".dfn-panel.on, .dfn-panel.activated").forEach(function(el){
            el.classList.remove("on");
            el.classList.remove("activated");
        });
    }
    if(target == "dfn" && !hitALink) {
        // open the panel
        var dfnPanel = document.querySelector(".dfn-panel[data-for='" + el.id + "']");
        if(dfnPanel) {
            dfnPanel.classList.add("on");
            var rect = el.getBoundingClientRect();
            dfnPanel.style.left = window.scrollX + rect.right + 5 + "px";
            dfnPanel.style.top = window.scrollY + rect.top + "px";
            var panelRect = dfnPanel.getBoundingClientRect();
            var panelWidth = panelRect.right - panelRect.left;
            if(panelRect.right > document.body.scrollWidth && (rect.left - (panelWidth + 5)) > 0) {
                // Reposition, because the panel is overflowing
                dfnPanel.style.left = window.scrollX + rect.left - (panelWidth + 5) + "px";
            }
        } else {
            console.log("Couldn't find .dfn-panel[data-for='" + el.id + "']");
        }
    } else if(target == "dfn-panel") {
        // Switch it to "activated" state, which pins it.
        el.classList.add("activated");
        el.style.left = null;
        el.style.top = null;
    }

});
</script>