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RTP Payload Format for DV Format Video draft-kobayashi-dv-video-00.txt

RTP Payload Format for DV Format Video draft-kobayashi-dv-video-00.txt. Akimichi Ogawa Keio University. Overview. RTP Payload format for DV(Digital Video) Payload format for NTSC, PAL(SD-VCR, HD-VCR, SDL-VCR) DV data comes directly after RTP Header Without Payload Specific Header

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RTP Payload Format for DV Format Video draft-kobayashi-dv-video-00.txt

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  1. RTP Payload Format for DV Format Videodraft-kobayashi-dv-video-00.txt Akimichi Ogawa Keio University

  2. Overview • RTP Payload format for DV(Digital Video) • Payload format for • NTSC, PAL(SD-VCR, HD-VCR, SDL-VCR) • DV data comes directly after RTP Header • Without Payload Specific Header • Payload consists of multiple DIF blocks • Payload length will be multiple of 80 bytes • uses 90kHz clock for RTP Timestamp

  3. DV(Digital Video) • Commonly used with DV camcorder • Uses DCT and VLC for Video Compression • No Inter Frame Compression • Audio is encoded with sampled data • 32kHz, 44.1kHz, 48kHz • PCM 16bit, 12bit

  4. Frame rate and Required Bandwidth for DV

  5. DIF sequence 0 DIF sequence 0 DIF sequence (N-1) DV Format Data in one video frame DIF sequence 0 Header section Subcode section VAUX section Audio & Video section DIF block 0 DIF block 1 DIF block 2 DIF block 148 DIF block 149 N = 10 for 525-60 system N = 12 for 625-60 system N = 10 for 1125-60 system N = 12 for 1250-60 system ID Data 0 1 2 3 79 Byte position number

  6. RTP Payload • DV data follows directly after RTP Header • No Format specific header • Payload consists of multiple DIF blocks • Payload length will be multiple of DIF block length • DIF block length is 80bytes • DIF block of different frame MUST be sent by different packets

  7. RTP Payload RTP Header 80 byte DIF block 80 byte DIF block 80 byte DIF block : :

  8. Timestamp • 90kHz clock will be used • Timestamp of the first data of the frame will be used for the whole frame • Timestamp SHOULD increment by multiple of nominal interval frame time

  9. Why 90 kHz ?

  10. Supports both Bundled and Unbundled Stream • Bundled Stream • Audio, Video, System data are sent together • Unbundled Stream • Audio and Video data are sent by separate RTP sessions

  11. Choice of Bundled and Unbundled Stream • The choice MUST be indicated as part of the assignment of the dynamic RTP type • It MUST be unchanged for the duration of the RTP session • To avoid complicated procedures of sequence number synchronization

  12. Unbundled Stream • If VAUX are sent, VAUX MUST be sent within a Video stream • Same Timestamp SHOULD be used for the data within the same frame • Use of L16 format for Audio when unbundled stream is used is RECOMMENDED

  13. Frame Rate • Sender MAY reduce frame rate by discarding Video and VAUX DIF blocks • Receiver SHOULD implement a error concealment strategy • Using previous image • Enable missing DIF blocks • Enable packet losses • Receiver SHOULD have the ability to process streams with NO VAUX and AAUX

  14. Open Issue • L16 is RECOMMENDED for unbundled audio • for 12bit audio, there are two possible ways • Translate 12bit -> 16bit • Defining a new encoding format • Like “non-Linear 12” • Where should the definition of the new encoding format be written • define it in our draft • edit a new draft

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