1 RTP Payload Format for DV Format Video draft-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 DV Format Data in one video frame DIF sequence 0 DIF sequence (N-1) Header sectionSubcode sectionVAUX sectionAudio & Video section DIF block 0DIF block 1DIF block 2 DIF block 148DIF block 149 DataID Byte position number N = 10 for system N = 12 for system N = 10 for system N = 12 for system

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 ::::

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