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RTP Payload Format for DV Video

RTP Payload Format for DV Video. draft-ietf-avt-dv-video-02.txt. updates 01 -> 02. Some minor changes We had feedback from implementers Some implementers consider DV audio only format is not necessary Audio for DV is shuffled

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RTP Payload Format for DV Video

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  1. RTP Payload Format for DV Video draft-ietf-avt-dv-video-02.txt

  2. updates 01 -> 02 • Some minor changes • We had feedback from implementers • Some implementers consider DV audio only format is not necessary • Audio for DV is shuffled • Reshuffling is needed to convert DV audio to common audio formats • Today’s CPU has enough performance for reshuffling • Compatibility with other audio format is much important

  3. Issues • When sending unbundled DV stream,,,, • Using legacy format (L16, DAT12, L20, L24) is RECOMMENDED • RECOMMENDED -> MUST ???? • Do not allow DV DIF block only audio • When sending DV audio only, use legacy audio format • Which do you think is better? • RECOMMENDED • MUST

  4. RTP Payload Format for 12 bits, 20bits and 24 bits DV Audio draft-ietf-avt-dv-audio-01.txt

  5. Changes(added non AIFF-C audio channel convention) • DV audio channel allocation • DAT12 audio mode in DV format has maximum of 8 channels • For example… • Audio with…. • Left, Right, Center, Woofer, Left Surround, Right Surround • AIFF-C can not specify “woofer” • AIFF-C only contains location information

  6. SDP format for audio channel convention a=fmtp:<payload type> channels:<channel convention> [<symbol1 [/symbol2…]>] ・　channel convention - AIFF-C (default) - DV ・　symbols (next page)

  7. Symbols used for DV(1) • L: Left channel of stereo • R: Right channel of stereo • M: Monoral signal • C: Center channel of 3,4,6 or 8 ch stereo • S: Surround channel of 4 ch stereo • LS, LS1, LS2: Left surround channel • RS, RS1, RS2: Right surround channel

  8. Symbols used for DV(2) • LC: Left center channel of 8 ch stereo • RC: Right center channel of 8 ch stereo • Q1: 0.7071LS + 0.7071RS • Q2: 0.7071LS - 0.7071RS • WO: Woofer channel • Lmix: L + 0.7071C + 0.7071LS • Rmix: R + 0.7071C + 0.7071RS • T: 0.7071C

  9. SDP example v=0 o=ikob 2890844526 2890842807 IN IP4 126.16.64.4 s=POI (Audio only) i=A Seminar of how to make Presentation u=http://www.koganei.wide.ad.jp/~ikob/index.html e=ikob@koganei.wide.ad.jp (Katsushi Kobayashi) c=IN IP4 224.2.17.12/127 t=2873397496 2873404696 m=audio 49170 RTP/AVP 112 113 a=rtpmap:112 L16/48000/2 a=rtpmap:113 DAT12/32000/4 a=fmtp:113 contents:DV L/R/C/WO Audio is sent using RTP payload type 112 and 113 Payload type 112 sends L16 audio Payload type 113 sends DAT12 audio DAT12 audio contains 4 channel audio : Left, Right, Center, Woofer

  10. Use of audio channels attribute • Audio “channels” attributes • AIFF-C (this is default) • DV • AIFF-C MUST be use if possible • DV is used when channel allocation is beyond AIFF-C convention

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