[NUT-devel] rfc drafting

Rich Felker dalias at aerifal.cx
Mon Nov 19 03:42:14 CET 2007


On Sun, Nov 18, 2007 at 02:48:51PM +0100, Michael Niedermayer wrote:
> that was the reason why i wrote it like that :)
> such streams exist and it even makes sense for them to exist ...
> just think of realtime communication over a low bandwidth channel
> (portable phones or something like that would be an example)
> i frames are many times bigger than p frames at the same quality
> so having p frames with lets say 10% intra coded blocks leads to
> lower delay than i frame would. and i frames at lower quality would lead
> to unacceptable flickering every time a low quality blocky I frame would
> be received
> so yes, i think all frames should be key frames in that case ...
> also the encoder can optimize the decission of which blocks to code as
> intra ...

I agree such codecs should exist, I just wonder whether considering
all frames to be keyframes is an appropriate solution. After all,
imagine a program using a file with such a codec as a source for
editing. "This frame is a keyframe" does not mean much if it doesn't
guarantee you can decode all frames with pts >= this_frame.pts without
significant error. You might as well just ignore the keyframe flag for
seeking then..

Rich



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