RE: [AVT] Working group last call: JPEG-2000 payload format

["Boudani Ali" <Ali.Boudani at thomson.net>]

>Can you please clarify why it isn't enough with a 90 kHz clock even for

>professional video? When is their need for time jitter related to when
a 
>frame was sampled needs to be smaller than what a 90kHz clock provide. 
>specially considering that most of the frame rates used will have 
>perfect match to a particular tick increment per frame. I don't think
we 
>have heard any such issues being raised in AVT before. If we do miss a 
>critical motivation then this applies to all our video payload formats,

>not only one.

I didn't say smaller. The RTP timestamp in the draft is used also as a
presentation time. So in that case, if you want to mix two frames, you
need the pixel precision (The clock frequency used in SD is 27MHz).
That's why I am saying that 90KHz (one and only) is not enough. If you
put "SHOULD be 90 KHz", that may be a solution since the user could then
put its frequency value in rtpmap (a=rtpmap:..../frequency) in the SDP
session.

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