Re: [rtcweb] H.261 encoding samples at typical bitrates - sign language example

David Singer <singer@apple.com> Sat, 07 December 2013 00:22 UTC

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From: David Singer <singer@apple.com>
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Date: Fri, 06 Dec 2013 16:21:41 -0800
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Subject: Re: [rtcweb] H.261 encoding samples at typical bitrates - sign language example
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On Dec 5, 2013, at 13:05 , Justin Uberti <juberti@google.com> wrote:

> Ow, my eyes...
> 
> The 256 kbps and lower clips are unusable. The 512 kbps clip is borderline, but might be usable if the framerate was cut in half.

Be careful, in a motion-prediction codec, moving the frames further apart in time increases the likelihood that motion prediction will fail, and thus may actually increase, or plateau, the bit-rate.

(many years ago I did experiments with 261 and 263 on this; these codecs have limited MV ‘reach’ and so really can exhibit this behavior)

David Singer
Multimedia and Software Standards, Apple Inc.