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AS-AP Archive and Preservation Early Draft Oliver Morgan Metaglue Corporation August 2010.

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Presentation on theme: "AS-AP Archive and Preservation Early Draft Oliver Morgan Metaglue Corporation August 2010."— Presentation transcript:

1 AS-AP Archive and Preservation Early Draft Oliver Morgan Metaglue Corporation August 2010

2 2 AS-AP Archive and Preservation Goals – define a standard MXF format for A&P – discuss and reach consensus on image formats, file structure, and metadata – reconcile with implementation practice – review and publish through AMWA – eventually, due-process standardization

3 3 Profiling MXF MXF is a massive standard – wide coverage – many details – many options – needs focus to specific applications Application Specification – defines broad choices for an application area – ex: Program Delivery, Versioning, Craft Editing, Contribution,... Shim – detailed constraints for specific uses

4 4 the universe of media formats media formats that can be carried in MXF Archive and Preservation Umatic (Application Spec) (Shim)

5 5 the universe of media formats media formats that can be carried in MXF Archive and Preservation Umatic (Application Spec) (Shim) Film NAVCC? (Sub-Shim)

6 6 the universe of media formats media formats that can be carried in MXF Archive and Preservation Umatic (Application Spec) (Shim) Film NAVCC? (Sub-Shim) Photo NARA?

7 7 Details and AS-AP Topics AS-03 case study/example – slides follow below AS-AP Strawman – “AMWA-AS-AP-Archive&Preservation-Spec-1a doc”

8 AS-03 Program Delivery Oliver Morgan Metaglue Corporation June 2009

9 9 AS-03 MXF Program Delivery File-Based Workflow Which file format? – Based on SMPTE Material Exchange Format (MXF) – The SMPTE MXF standards cover a very wide range of parameters and user needs – AS-03 is a vendor-neutral interoperability profile of MXF – The NGIS HD and NGIS SD “shims” focus the AS-03 profile on PBS programming distribution requirements – Other “shims” are anticipated for other organizations

10 10 Why MXF? There are many file formats to choose from – almost as many formats as there are recording devices – that is fine so long as we all use the same server… The industry has been searching for a format that can become as ubiquitous as SDI – Goal is a non-proprietary specification – SMPTE started work in earnest in 1997 – Universal Wrapper Compression Agnostic, Bitrate Agnostic Application Agnostic Allow Mix and Match – Universal Metadata Both Standard and User-Defined

11 11 MXF History MXF was published in 2004 – 700 pages of specifications – a disruptive technology Developed 1997 to 2003 with lots of testing – published documents needed corrigenda & amendment – initial implementations were rough Nonetheless, user uptake gathered momentum

12 12 MXF Today Libraries of AAF and MXF files exist today – have existed since 2002 Primarily essence files – also include valuable customer metadata Some examples – Digital Cinema Releasing: 50,000 per year ? – Digital Cinema Post Production: scads – Commercial TV: 50,000 per month ? – Shoah Foundation: 50,000 per year – Culpeper Archive: will be 250,000 per year – Government: 1 per minute per aircraft

13 13 Some of the (many) kinds of MXF Files MasterMob V1 A2 A1 TC AX DM UMID EssenceData UMID FileSourceMob V1 A2 A1 TC AX DM UMID MasterMob V1 A2 A1 TC AX DM UMID FileSourceMob V1 A2 A1 TC AX DM UMID MasterMob V1 A2 A1 TC AX DM UMID EssenceData UMID FileSourceMob V1 A2 A1 TC AX DM UMID

14 14 FileSourceMob V1 A2 A1 TC AX DM UMID Some more… FileSourceMob V1 A2 A1 TC AX DM UMID EssenceData UMID EssenceData UMID MasterMob V1 A2 A1 TC AX DM UMID PhysicalSourceMob V1 A2 A1 TC AX DM UMID MasterMob V1 A2 A1 TC AX DM UMID PhysicalSourceMob V1 A2 A1 TC AX DM UMID

15 15 AS-03 File (MXF OP1a) MasterMob V1 A2 A1 TC AX DM UMID EssenceData UMID FileSourceMob V1 A2 A1 TC AX DM UMID

16 16 Overall View Of An AS-03 File

17 17 MXF “Package” Package V1 A2 A1 TC AX DM UMID Tracks any number – Picture, Sound – Descriptive Metadata – Data, User-defined – Sequences – any length Descriptive Metadata (DM) – any number, any scheme – SMPTE, MXF, User-defined Timecodes any number, any frame rate – SMPTE, Keycode, GPS – Links to other Mobs – as needed – internal or external Media Object Package Identifier SMPTE UMID – Software GUID – User-defined –

18 18 AS-03 Goals The goal of the AS-03 Program Delivery project is create specifications and sample files for MXF distribution of finished programs and program segments with associated metadata. The content of these files is not intended for further processing before delivery to the consumer – Direct Playout, from any server Specifications will be composed of a set of general constraints plus one or more "shims" that are directed to specific applications

19 19 How? AS-03 defines sets of constraints upon the use of the features of the MXF file format for use in the program delivery chain. The intent of these constraints is to minimize the number of options that must be considered by implementers of individual devices within the system, thus increasing the reliability and interoperability of the overall system.

20 20 Specification A set of general constraints plus one or more "shims" that are directed to specific applications: for example, one for "NGIS HD", one for "NGIS SD", one for "Broadcaster A", and so on. This allows us to remain flexible while maintaining our focus on delivering this project according to the proposed schedule We can move issues between the general text and the "shims" to optimize the split between generality and specific application requirements

21 21 AS-03 Coverage The specifications will cover both SD and HD program content encoded in long GOP MPEG2 or H.264 constrained to specific bit rates and GOP structures. Captioning and VBI data will be carried separately from video. Program audio will be constrained to specific channel repertoires and bit rates. Essence will be interleaved to ensure preservation of sync during distribution – MPEG V-ES in SMPTE 381 – PCM in SMPTE 382 – AC-3 ES in SMPTE 339 in SMPTE 382 – VBI in SMPTE 436 – Alll multiplexed in SMPTE 379M Generic Container

22 22 AS-03 Metadata Different metadata sets appropriate to each distribution application will be carried in the MXF header A small summary metadata set will be present in all files – will carry a few metadata items gathered from the application-specific metadata – to facilitate content identification, routing and multiplexing – DMS-AS-03 For NGIS HD and SD – Slate metadata Program ID (P ) Total Run Time (TRT) Start/End of Message (SOM and EOM) pairs Active Format Description (AFD) Feature Indicators (CC, DVS, SAP, Vchip, Rating) Language Codes NOLA code Title Media type (signal type) – Optional PB/Core

23 23 AS-03 Constraint Tabulation - Picture DimensionDescriptionAS-03 Constraint AS-03 Values NGIS HD Constraint NGIS HD Values Segment Duration what is the range of program items to be covered Gentle0:00:01:00 and upModerate0:00:05:00 to 3:00:00:00 Program bitratehow many bits per second at real time Gentle~3Mbps to ~50 Mbps Strong25 Mbps Mpbs for HD Picture formatPicture raster and aspect ratio Moderate480i 4:3, 1080i 16:9 Strong1080i 16:9 for HD Transport Bitratehow many bits per second in transit NoneN/AStrong<35 Mbps Picture Essence Schemes what picture signal schemes (compression or sampling or other) are encountered in programs GentleMPEG2 all GOPs AVC all GOPs 4:2:0 or 4:2:2 StrongATSC & MPEG 2 long GOP

24 24 AS-03 Constraint Tabulation - Sound DimensionDescriptionAS-03 Constraint AS-03 Values NGIS HD Constraint NGIS HD Values Sound Essence Schemes what sound signal schemesModeratePCM AC-3 -same- Sound Language repertoire what primary sound languages may be present NoneanyModerateen-us one other ? Track Listingswhat combinations of picture sound and data tracks are encountered in programs Strong1 x Main Sound (stereo or 5.1) 1 x SAP (opt) 1 x DVS (opt) Others opt up to a total 8 pairs PCM pairs shall be used for Stereo programming StrongPBS Published Audio Configuration (surround plus 4 pairs)

25 25 More Constraints – Captions, Metadata DimensionDescriptionAS-03 Constraint AS-03 Values NGIS HD Constraint NGIS HD Values Caption Essence Schemes what captions signals schemes StrongCEA-608, CEA-708 & SMPTE 436M -same- Caption Languages what captions languagesNoneanyStrongen-us and one other Program identification what identifiers are required GentleOne of: ISAN Ad-ID House (per shim) UUID StrongHouse (PODS) Intimate metadata what metadata must be carried with the program item ModerateProgram Ident (reqd) Track Ident (reqd) Language Ident (reqd) other per shim Program Segmentation (opt) ModeratePODS summary (reqd) PBCore (opt)

26 26 More Constraints – MXF-specific DimensionDescriptionAS-03 Constraint AS-03 Values NGIS HD Constraint NGIS HD Values Segment Duration what is the range of program items to be covered Gentle0:00:01:00 and upModerate0:00:05:00 to 3:00:00:00 MXF StructureMXF-specific Operational Pattern StrongOP1A internal-same- MXF Structure (continued) MXF-specific Index Tables StrongFull Index Tables-same- MXF Structure (continued) MXF-specific Partitioning NoneN/A-same-

27 27 Reference Implementation Utilities have been produced to wrap test essence and metadata into AS-03 files, to unwrap the files and compare the inputs and outputs. These will be used throughout the project to illuminate design issues and to perform regression testing Using mxflib open source – scripts to wrap and unwrap – design testing is performed with a custom scripting application simpler functions will be included in NGIS workflow

28 28 Sample Files Test files will be created during the development, including “golden” (engineered good), and “silver” (real-world, proven good) Silver streams encoded by users – for NGIS HD and SD encoded by PBS Several encoders Actual “Cringely” and other programming Golden test streams – Golden test sequence uses synthetic test patterns MPEG Video, AC3, PCM, CEA 608 and 708

29 29 AS-03 Testing AS-03 builds on earlier work on AS-PBS Basic methodology – make specs and sample files available to all vendors – regular telephone discussion – iterative testing – eventually, publish via the AMWA Server vendors – Omneon, Harris, Thomson, Seachange, GVG, 360 Systems, Sony, Pinnacle, … Now starting testing with transcoder vendors

30 30 Segmentation Some files cut to length – SOM = 0, EOM = total duration – e.g. AS-03 NGIS Some files include preroll/postroll – SOM, EOM traditionally specified using timecode – Duration is less error-prone than EOM SOM and EOM/Duration pairs – sequence of non-overlapping segments – may be separated by black fill, or back-to-back (not AS-03) Segments may be in individual files

31 31 MXF “Package” Package V1 A2 A1 TC AX DM UMID Tracks any number – Picture, Sound – Descriptive Metadata – Data, User-defined – Sequences – any length Descriptive Metadata (DM) – any number, any scheme – SMPTE, MXF, User-defined Timecodes any number, any frame rate – SMPTE, Keycode, GPS – Links to other Mobs – as needed – internal or external Media Object Package Identifier SMPTE UMID – Software GUID – User-defined –

32 32 The Package Derivation Chain CompositionPkg FX V1 A2 A1 V2 UMID EssenceData UMID PhysicalSourcePkg V1 A2 A1 TC AX DM UMID EssenceData UMID FileSourcePkg V1 A2 A1 TC AX DM UMID MasterPkg V1 A2 A1 TC AX DM UMID FileSourcePkg V1 A2 A1 TC AX DM UMID

33 33 MXF Operational Patterns

34 34 SOM/EOM in MXF Structural Metadata (1) Material Package 01:00:00:00 01:05:00:00 01:10:00:00 01:15:00:00 File Package Composition Package Picture Sound Timecode Picture Sound Picture Sound Descriptive Metadata Picture 2:00:00 4:30:00 1:00:00 6:00:00 1:20:00 20:00 2:20:00 …

35 35 SOM/EOM in MXF Structural Metadata (2) Material Package 01:00:00:00 01:05:00:00 01:10:00:00 01:15:00:00 Descriptive Metadata 2:00:00 4:30:00 1:00:00 6:00:00 1:20:00 20:00 2:20:00 … File Package Picture Sound Timecode Picture Sound Descriptive Metadata

36 36 CRC and Signature Requirements for verification of file content? – transport/storage/delivery errors – authentication – file corruption during processing – integrity of repurposing (e.g. track swapping) Techniques in AS-02 – MD5 – CCITT CRC-16 – Castagnoli CRC-32 Techniques from SMPTE DCP Encryption – SHA-256/SHA-512 Secure Hash – full MIC and encryption Other techniques – Signature – Hash essence together with the author’s public key

37 Thank You Questions? Oliver Morgan


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