Guidelines for Implementation: DASH-IF Interoperability Points

1. Document editing notes

Documentation: https://dashif.org/DocumentAuthoring/

Example document repository: https://dashif.org/DocumentAuthoring/

Live discussion in #document-authoring on Slack.

Scope Disclaimer

2. Introduction

As a historical note, the scope of the initial DASH-AVC/264 IOP, issued with version 1 of this document [1] was the basic support high-quality video distribution over the top. Both live and on-demand services are supported.

In the second version of this document [2], HD video (up to 1080p) extensions and several mul-tichannel audio extensions are defined.

In this third version of the DASH-IF IOP document, two new DASH-264/AVC IOPs are defined. Detailed refinements and improvements for DASH-IF live services and for ad insertion were added in these IOPs. One of these IOP is the superset of the simpler one. Additionally, two cor-responding IOPs are defined to also support HEVC [19]. In both cases, AVC and HEVC, the more advanced IOP adds additional requirements on the DASH client to support segment pars-ing to achieve enhancement of live services. This structuring separates the Media Profiles from DASH features.

In the fourth version, beyond minor improvements, corrections and alignment with MPEG-DASH third edition, the key additions are extensions for next generation audio and UHD/HDR video.

This document defines the IOPs in Table 1 and Extensions in Table 2. The Implementation Guideline’s version in which each IOP or Extension was added is also provided in the tables.

Note that all version 1 IOPs are also defined in version 2 and therefore referencing version [2] is sufficient.

Note that all extensions defined in version 2 of this document are carried over into version 3 without any modifications. In order to maintain a single document, referencing in Table 2 is restricted to this document.

In addition to the Interoperability points in Table 1 and extensions in Table 2, this document also defines several other identifiers and other interoperability values for functional purposes as documented in Table 3.

DASH-IF supports these guidelines with test and conformance tools:

• DASH-IF conformance software is available for use online at http://dashif.org/conformance.html [32]. The software is based on an open-source code. The frontend source code and documentation is available at: https://github.com/Dash-Industry-Forum/Conformance-Software. The backend source code is available at: https://github.com/Dash-Industry-Forum/Conformance-and-reference-source.

• DASH-IF test assets (features, test cases, test vectors) along with the documentation are available at http://testassets.dashif.org [31].

• DASH Identifiers for different categories can be found at http://dashif.org/identifiers/ [33]. DASH-IF supporters are encouraged that external identifiers are submitted for doc-umentation there as well. Note also that DASH-IF typically tries to avoid defining iden-tifiers. Identifiers in italics are subject to discussion with other organizations and may be deprecated in a later version.

Technologies included in this document and for which no test and conformance material is provided, are only published as a candidate technology and may be removed if no test material is provided before releasing a new version of this guidelines document.

3. References

See v4.3 references

4. Conventions, Context, Terms and Definitions

4.1. Relation to MPEG-DASH

4.2. Conventions

• usage of keywords

• Formats

see v4.3 and bug filed by Sander

4.3. Abbreviations

4.4. Terms and Definitions

5. General DASH Features

5.1. Architecture

• High-level end-to-end streaming architecture

• ABR Encoder

• Encryption

• File Format Architecture

• DASH Packager and MPD Generator

• Origin Server

• CDN

• DASH Client

  • DASH access client

    • Selection

    • Download

  • Media Pipeline

Reference other DASH activities (Ingest, CPIX, SAND, etc.)

(re-use low-latency architecture)

5.2. Formats

5.2.1. MPD

• General high-level requirements

5.2.2. Segments

• Segment Formats in DASH

• Requirements

• Connect to CMAF and cmf2

5.2.3. Segment Addressing Schemes

• SegmentTemplate

  • $Number$ and $Time$

• Self-Initializing

  • Single Segment with Segment Index

• Explain why we use different addressing

• Follows clause 3.5 of https://dashif-documents.azurewebsites.net//DASH-IF-IOP/pull/210/DASH-IF-IOP.html#timing-addressing

5.3. Protocol Considerations

5.4. Location and Reference Resolution

5.5. Client-Server Synchronization

https://dashif-documents.azurewebsites.net//DASH-IF-IOP/pull/210/DASH-IF-IOP.html#timing-sync

5.6. Client Reference Model

(new clause) point to CTA WAVE Device Playback

5.7. Media Presentation Data Model

5.7.1. Timing Model

• Features

• Content Offering Requirements and Recommendations

• Client Requirements and Recommendations

See 3.2.7 and document from Sander

https://dashif-documents.azurewebsites.net//DASH-IF-IOP/pull/210/DASH-IF-IOP.html#timing-period

https://dashif-documents.azurewebsites.net//DASH-IF-IOP/pull/210/DASH-IF-IOP.html#timing-representation

5.7.2. Content Annotation and Selection

• Features

• Content Offering Requirements and Recommendations

• Client Requirements and Recommendations

See 3.9 and document from Sander

5.7.3. Adaptive Switching

• Features

• Content Offering Requirements and Recommendations

• Client Requirements and Recommendations

(Adaptation Set, segment and subsegment alignment)

https://dashif-documents.azurewebsites.net//DASH-IF-IOP/pull/210/DASH-IF-IOP.html#timing-segmentalignment

5.7.4. Segment Timing

https://dashif-documents.azurewebsites.net//DASH-IF-IOP/pull/210/DASH-IF-IOP.html#timing-sampletimeline

• @duration

• Segment Timeline

• Segment Index

5.8. Bandwidth Signaling

• Minbuffertime

• @bandwidth

• Segment Index

See clause 3.2.8

5.9. Service Types

On-Demand Services

• On-Demand Services

  • MPD Signaling

  • Reference to clause X

• Live Services

  • Content availability, time shift window and presentation delay concepts (Sander’s 3.8-3.9.4)

  • MPD Signaling

  • MPD updates (Sanders 3.8.5)

  • Reference to clause X

5.10. Media in DASH

5.10.1. Media in one Period

• Features

• Content Offering Requirements and Recommendations

• Client Requirements and Recommendations

• Text from Sander 3.6

5.10.2. Media Across Periods

• Features

• Content Offering Requirements and Recommendations

• Client Requirements and Recommendations

• Text from Sander 3.7

5.10.3. Requirements and Recommendation for Media Codecs in DASH

• General Statements on how to add

• Capabilities

• Requirements on what needs to be defined (CMAF relation)

5.11. Events

5.12. Remote Elements

Text from Sander 3.9

https://dashif-documents.azurewebsites.net//DASH-IF-IOP/pull/210/DASH-IF-IOP.html#timing-xlink

5.13. Profiles and Interop

5.14. Examples

6. On-Demand Services

7. Live Services

https://dashif-documents.azurewebsites.net//DASH-IF-IOP/pull/210/DASH-IF-IOP.html#timing-dynamic

8. Content Replacement and Ad Insertion

• Content conditioning and splicing

9. Content Protection and Security

10. Video in DASH

(focusses on very specific issues following the general requirements from clause 4)

10.1. General

10.1.1. MPD and Adaptation Set Signaling

10.1.2. Segment Formats

10.2. H.264/AVC

10.3. H.265/HEVC

10.4. VP9

11. Audio in DASH

11.1. General

11.1.1. MPD and Adaptation Set Signaling

11.1.2. Segment Formats

11.2. (Codec 1)

11.3. (Codec 2)

12. Subtitles in DASH

12.1. General

12.1.1. MPD and Adaptation Set Signaling

12.1.2. Segment Formats

12.2. (Codec 1)

(add a table with media profiles and reference CMAF) (create a clause with specific issues)

12.3. (Codec 2)

13. Other DASH Features

13.1. Seek Preview and Thumbnail Navigation

14. Annex Exclusions from MPEG-DASH