1. Windows Media 格式内幕 凌梅 Development Lead Windows Digital Media Division Microsoft Corporation

3. Agenda Opportunities with WM Opportunities with WM Windows Media Format SDK Windows Media Format SDK

4. Windows Media 9 Series Core Promises Unmatched Audio/Video Quality Dramatically Improved Playback Most Comprehensive Platform 20% better compression across the board extends industry lead20% better compression across the board extends industry lead New voice/screen codecs, video smoothing boost dial-up qualityNew voice/screen codecs, video smoothing boost dial-up quality New HD video & 5.1 audio delivers home-theater experiencesNew HD video & 5.1 audio delivers home-theater experiences Fast Streaming provides instant-on/always-on experienceFast Streaming provides instant-on/always-on experience Intelligent Streaming optimizes the experienceIntelligent Streaming optimizes the experience Fast & flexible player with industry’s first Smart JukeboxFast & flexible player with industry’s first Smart Jukebox Industry’s best scalability, reliability & manageabilityIndustry’s best scalability, reliability & manageability End-to-end extensible architectureEnd-to-end extensible architecture Improved economics throughoutImproved economics throughout

5. File Codecs DShow DRM Networking DShow DRM License Acquisition Windows Media Server WMS Admin Object WM Server MMC Admin WM Server Web Admin Server Services WM Format SDK Movie Maker Producer Third Party Tools WM Encoder & OCX DRM License Creation Content Discovery/ Metadata IIS Networking DRM Codecs File WM Format SDK WMP.DLL Windows Media Player Windows Media Player OCX Authoring On-Line Services Playback Windows Media 9 Series Platform Component Drill-down

6. WM Codec Parameters Into 3rd generation codecs v8 Into 3rd generation codecs v8  Encoding utility Support streamed / local playback Support streamed / local playback WM is WM is  ASF (WMV / WMA)  Codecs  DRM v1 and v7 GOAL GOAL  Smallest size for quality (e.g. 1/2 MP3)  Near DVD @ 500kbps  Maintain consistent quality

7. Video Smoothing (Frame Interpolation) Generates missing frames at playback time using optical-flow analysis Generates missing frames at playback time using optical-flow analysis Improves perceived video quality (motion smoothness) at lower data rates Improves perceived video quality (motion smoothness) at lower data rates Can be used to improve quality or save bandwidth by encoding fewer frames Can be used to improve quality or save bandwidth by encoding fewer frames  Bandwidth reduction reduces operating cost for ICPs  E.g. MSNBC encodes only 15 frames/sec, but user of WM9 Player will experience full frame rate

8. Video Smoothing demo demo

9. WMV Screen 9 Highly efficient compression engine for “palletized video” Highly efficient compression engine for “palletized video”  Typical scenario is capturing application/desktop output for training/demo  Entire desktop can be compressed and transmitted at rates as low as 28kbps!  Up to 100X more efficient than commonly used Run- length-encoding (RLE) Original Version (V7) shipped in 2000 Original Version (V7) shipped in 2000 Version 9 improves in both picture quality and CPU usage Version 9 improves in both picture quality and CPU usage  More efficient handling of continuous-tone images and window dragging/scrolling

10. Screen Codec demo demo

11. WMA Professional 9 New high-performance audio codec to handle greater than CD resolution/channels New high-performance audio codec to handle greater than CD resolution/channels  Up to 96Khz sampling rate, 24-bits, and 8 channels (“7.1”)  CD is stereo at 44Khz using 16-bit samples  Targets are multi-channel music distribution and movie sound tracks at broadband rates More efficient than existing technologies: More efficient than existing technologies:  Twice as good as Dolby Digital (AC-3) and DTS used in DVDs  Blind listening test shows WMA Pro at 768Kbps outperforms all existing codecs in the market

12. WMA 9 Pro Codec demo demo 192K WMA Pro 5.1 vs. 192K MP3

13. WMA Voice 9 Unique “hybrid” voice and music coder for low data rates (<= 20Kbps). Unique “hybrid” voice and music coder for low data rates (<= 20Kbps).  First codec to properly handle mixed mode content (e.g. news plus musical commercial)  Uses an auto/manual classifier to detect voice/music  Applies appropriate coding mode for each segment Voice mode: new proprietary voice codec Voice mode: new proprietary voice codec  20% better than ACELP shipping today (used by Real and WM) Music mode: WMA algorithms Music mode: WMA algorithms

14. WMA 9 Voice Codec demo demo WMA Voice vs. AMR (3G-GSM)

15. Windows Media Format Our Advantages Our Advantages  Extensible file format  Support advanced MS and 3rd party codecs  Support rich media  Scalable  Efficient local playback  Efficient Streaming (HTTP +)  High capacity Media Servers  Author once, playback anywhere  Streams 28.8Kbps  1Mbps broadband  Replay PC’s, PDA’s, Consumer Elec.  Car stereos, Cellphones, In home devices, PD’s

16. Windows Media Format File Container Supports files as large as 17 million terabytes Supports files as large as 17 million terabytes Supports multi-bitrate audio, video streams in a file Supports multi-bitrate audio, video streams in a file Stores media and metadata in one file Stores media and metadata in one file  Metadata  Title, copyright, author, markers, script commands, etc.  ID3 v1, v2 music meta-information  Media  Audio, Video, rich media and Script Commands (URLs, CC) AudioStream Video Stream #1 Video Stream #n Script Stream Timeline Rich Stream

17. Windows Media Format File Container (Cont.) Able to select a stream, based on available bandwidth Able to select a stream, based on available bandwidth Interleaved data is optimal for HTTP Interleaved data is optimal for HTTP Files can be read sequentially, avoiding expensive seeks Files can be read sequentially, avoiding expensive seeks Timeline based synchronization Timeline based synchronization Bursty data can be smoothed Bursty data can be smoothed  Send Timestamp (milliseconds)  Presentation Timestamp (Rational time units) Presentation Time Presentation Time Send Time

18. Rich Feature Set Time-code with Frame accurate seeking support Time-code with Frame accurate seeking support Live DRM Live DRM Video Smoothing (Frame Interpolation) Video Smoothing (Frame Interpolation) Rich Media Streaming Rich Media Streaming VBR streaming/progressive down-load optimizations VBR streaming/progressive down-load optimizations Bandwidth sharing Bandwidth sharing Enables fast stream Enables fast stream MBR audio and multiple resolution MBR Video MBR audio and multiple resolution MBR Video PhotoMotion PhotoMotion

19. Photo Motion demo demo

20. Windows Media Format SDK Win32 only (Win98, WinMe,Win2000, WinXP) Win32 only (Win98, WinMe,Win2000, WinXP) COM-style interface COM-style interface Support audio/video/script authoring and playback Support audio/video/script authoring and playback Enhance metadata authoring and playback Enhance metadata authoring and playback DRM support (encryption and decryption) DRM support (encryption and decryption) Streaming support (“net-read”, “net-write”) Streaming support (“net-read”, “net-write”) Ideal for applications that handle dataflow Ideal for applications that handle dataflow Target solutions Target solutions  Jukebox, Live Encoder, Video Editor Write Write Interface Read Interface.wma or.wmv file Raw or Compressed Audio Raw or Compressed Video Script Commands Header MetaData IP Network Raw or Compressed Audio Raw or Compressed Video Script Commands Header MetaData

21. Read with WM Format SDK IWMReader IWMReader  Read WM data.  WMCreateReader IWMReaderAdvanced IWMReaderAdvanced  User driven clock  Manual stream selection  Custom buffer allocation  QI from IWMReader IWMSyncReader IWMSyncReader  Synchronous Read  No streaming support  Ideal for editing app  WMCreateSyncReader

22. Encode with WM Format SDK IWMWriter IWMWriter  Encode and write WM data  WMCreateWriter IWMWriterAdvanced IWMWriterAdvanced  Set output sink(s)  Directly write compressed data  QI from IWMWriter Output to different destinations Output to different destinations  Output to file (WMCreateWriterFileSink)  Output to port (WMCreateWriterNetworkSink)  Output to WM Server (WMCreateWriterPushSink)  Custom sink

23. Encode with WM Format SDK (Cont.) Basic calls Basic calls  hr = WMCreateWriter( NULL, &pWriter );  hr = pWriter->QueryInterface( IID_IWMWriter, ( VOID ** )&pWriter );  hr = pWriter->SetProfile( pProfile );  hr = pWriter->SetOutputFilename( outfile );  hr = pWriter->BeginWriting( );  Hr = pWriter->WriteSample();  …  Hr = pWriter/->EndWriting ();

24. Edit with WM Format SDK IWMMetadataEditor IWMMetadataEditor  WMCreateEditor  Open  Close  QI for IWMHeaderInfo IWMHeaderInfo IWMHeaderInfo  Read and edit header attributes

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