Standards' Perspective - MPEG DASH overview and related efforts


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Presented in the IMTC MPEG DASH webinar, February 16th 2012

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Standards' Perspective - MPEG DASH overview and related efforts

  1. 1. DASHStandards‘ perspective: MPEG DASH overview and related efforts Thomas Stockhammer Qualcomm Incorporated
  2. 2. Agenda• Review of what is DASH• Latest Status in MPEG DASH• Profile Discussion• DASH PG and IMTC• Summary 2
  3. 3. Apple HLS MPEG 2008 MS SS 2010 2008 OIPF W3C 2009 2011?3GPP DASH others2009 2011 Open Standard Delivery Format 3
  4. 4. DASH in a Nutshell• What: Video streaming solution where small pieces of video streams/files are requested with HTTP and spliced together by the client. Client entirely controls delivery.• Why: reuse widely deployed standard HTTP servers/caches for scalable delivery, e.g. existing Internet CDNs; traverse NAT/Firewalls; simple rate adaptation; fixed-mobile convergence; convergence of services, etc.• Use case: Accessing OTT video streaming services over any access network to any device HTTP over any Access Network (fixed, Media mobile)Preparation Media HTTP HTTP Origin Servers Caches
  5. 5. Example Deployment Architecture Original • Original content encoded into video streams content at different media rates Content Media player Preparation • Segments video streams into HTTP resources • MPD file generated for the video files • URL generated for MPD file Ingestion component • All intelligence is here • Accesses MPD file based on URL & makes requests for appropriate video files • Continually monitors and adjusts media rate based on network conditions, etc. HTTP delivery Serving Cloud HTTP/IP(HTTP web caching servers) network DASH client Any radio access: any cellular, WiFi, parallel delivery 5
  7. 7. MPEG DASH Status• ISO/IEC 23009-1 DIS ratified in November 2011 to move to IS – document is now at ITTF for final processing – Final text is made available through liaison to 3GPP and others – TC1_SG29_WG11/ – made available publicly for free after ITTF completes final processing 03/2012.• Same publication timeline for – extensions to ISO base media FF to support DASH 14496-12/AMD 3 – Common Encryption 23001-7 with AES-128 CTR• Other documents: – Conformance and Reference Software (see WD 23009-2) – Technical Report on Implementation Guidelines (see WD 23009-3) 7
  8. 8. Typical Uses Cases• MPEG-DASH supports simple and advanced use cases: – On-Demand, Live and time-shift (nPVR) streaming – Dynamic ad-insertion – Dynamic update of program – Delivery of same content on three screens – Delivery of any multimedia content (2D, 3D, animation, graphics, multiview, subtitles, text, etc.), not just AV – Support of multiple languages and different audio configuration – etc.• Simple use cases can be gradually extended to more complex and advanced ones
  9. 9. What is specified – and what is not?Media Presentation on HTTP Media DASH ClientServer Presentation Description Segment DASH Access Engine Resources on-time http located by requests to HTTP-URLs segments Media Engines HTTP HTTP/1.1 Access Client 9
  10. 10. Media Presentation Data Model • Media Presentation Description (MPD) describes accessible Segments and corresponding timing Segment Info Initialization Segment Presentation Media Segment 1 Period, start=0sPeriod, start=0s •start=100 Representation 1 •baseURL= •bandwidth=500kbit/s… … •width 640, height 480 Media Segment 2 Adaptation Set 1 … start=10s, start=100s Segment Info video… duration=10s Media Segment 3 start=20s Adaptation Set 2 Template: audio ./dash-5-$Number$Period, start=295s …… Representation 2 •bandwidth=250kbit/s … •width 640, height 480 … Media Segment 20 Splicing of Selection of start=190s arbitrary content Components/Tracks Select/Switch of 10 Bandwidth
  11. 11. Key feature – Common Timeline• Representations in one Period share common presentation timeline – presentation time of access unit within the media streams is mapped to the global common presentation timeline – enables synchronization of different media components and seamless switching of different coded versions of the same media components• Other timelines – segment availability times (mapped to UTC clock) – internal media decode time (not exposed on DASH level) 11
  12. 12. Client-Side Process Advertisement Back to video Segments Insertion 250 Kbps 500 Kbps 1 Mbps Segment 30s Period 12s Period 20s Period Process  Factors relevant for Representation  Client downloads the MPD file selection  Client downloads segment by segment based  Buffer conditions on playout process  Network conditions  Bitrate determined by client  User change in resolution – ex: full screen  Device activity and resources
  13. 13. Switching Support Features• Segment Alignment – permits non-overlapping decoding and presentation of segments from different Representations• Stream Access Points (SAPs) – presentation time and position in segments at which random access and switching can occur• Bitstream Switching – concatenation of segments from different Representations results in conforming bitstream• Media Stream Structure Similarity – permits switching at Open GOP boundaries• Alignment and SAPs can also apply for Subsegments 13
  14. 14. Segments• ISO/IEC 23009 focuses on Segment formats based on MPEG container formats. Specifically, – in 6.3, Segment formats are described for use with Media Segments based on the ISO Base Media File Format as defined in ISO/IEC 14496-12; – In 6.4, Segment formats are described for use with Media Segments based on the MPEG-2 Transport Stream as defined in the ISO/IEC 13818-2;• In both cases the Segment formats are defined such that the Media Segment formats comply with the respective container formats.• Guidelines for adding other Segment formats are provided in Annex F. 14
  15. 15. ISO BMFF DASH Segmentsftyp moov moof mdat moof mdat moof mdat Initialisation styp sidx moof mdat moof mdat Segment• binary information in ISO box structure on Media – Accessible units (one or multiple fragments) Segment – Each unit is described by • Byte range in the segments • Accurate presentation duration (seamless switching) • Presence and timing of stream access positions• Provides a compact bitrate-over-time profile – Can be used for intelligent request scheduling
  16. 16. Summary: DASH Selected Feature List• Live, On-Demand and Time-shift services• Independency of request size and segment size (byte range requests)• Segment formats – ISO base media FF and MPEG-2 TS – guidelines for integrating any other format – Are codec independent• Support for server and client-side component synchronization (e.g., separate and multiplexed audio and video)• Support for efficient trick mode• Simple splicing and (targeted) ad insertion• Multiple base URLs for the same content• Clock drift control for live sessions• DASH metrics for reporting the session experience• Profile: restriction of DASH and system features (claim & permission)• Content Descriptors for Protection, Accessibility, Rating, etc. – Enables common encryption, but different DRM (DECE-like) 16
  17. 17. DASHPROFILES 17
  18. 18. MPEG Profiles• Set of restrictions on the offered Media Presentation (MPD & Segments)• can also be understood as permission for DASH clients that only implement the features required by the profile to process the Media Presentation• Profiles defined in ISO/IEC 23009 (as below). More restrictions may be added Full Profile ISO Base media file main MPEG-2 ISO Base ISO Base MPEG-2 TS media file media file TS main format On format simple Demand Live 18
  19. 19. Profile Discussions beyond MPEG• Main motivation: – broad availability of clients supporting profile – enable deployment options in CDNs• Client Profile – support for one/multiple content profile – support for multiple addressing schemes – support for efficient, but still simple switching scheme• Media Presentation profile – Media presentation offering with one content profile, one switching scheme and one addressing scheme 19
  21. 21. DASH Promoters Group• Informal collaboration of companies that have committed or at least significant interest to deploy an open standard for HTTP-based streaming based on DASH.• Effort may include recommending profiles, codecs, DRM• Just started to create PR information, white papers, licensing, attend conferences, demos, interoperability efforts and so on• Current Members: Microsoft, Qualcomm, Netflix, Samsung, Ericsson, Akamai, AEG, Harmonics, Adobe, and many more have joined recently, please check• Significant interest from content providers (globally), operators, device manufacturers, etc.• Interested companies are invited to listen in and/or join 21
  22. 22. Profile Considerations @ DASH PG• Deployable industry profile – Based on combination of ISO BMFF live and On- Demand profile with some restrictions – Core Content Profile based on common codecs: H.264/AVC MP@3.0, HE-AAC, SMPTE TT, and Common Encryption – Extensions into various dimensions (HD, 3D, MC audio, low latency)• Establishment through successful interoperability of multiple/many vendors 22
  23. 23. IMTC Potential Role• Provide framework and credibility for interops• Joint work between DASH PG and IMTC – Define test cases for deployment profiles – organize interop for DASH including different device types (mobile, tablet, STV, iTV) – in case of successful interop promotion• Problem right now: – April is too soon (clashes with NAB and 3GPP SA4) – October may be too late 23
  24. 24. DASHSUMMARY 24
  25. 25. Summary• MPEG DASH standardization is completed – harmonized industry standard for OTT video – applicable to TV and mobile world• Working towards deployments: – Conformance and Reference SW in MPEG – Implementation Guidelines (3GPP and MPEG) – Integration into 3GPP RANs (3GPP) – Integration into browser environment ( – Promotion of the technology: events, PR, etc. (DASH PG) – Definition of deployable industry profile (DASH PG) – Multivendor demonstrations (MWC, NAB, IBC, etc.) – Official Interoperability tests (IMTC)• Support for all activities welcome and desirable 25
  26. 26. DASHTHANK YOU 26