[FFmpeg-devel] [RFC] better ogg seeking, keyframes only

Diego Biurrun diego
Thu Nov 6 01:04:16 CET 2008

On Sun, Mar 23, 2008 at 04:37:05PM +0100, Diego Biurrun wrote:
> On Wed, Mar 19, 2008 at 01:16:16PM +0100, Reimar D?ffinger wrote:
> > I admit this is a rather ugly patch, but it improves things a lot, so
> > maybe you can have a look and get it committable.
> > There are several issues with seeking: for audio, PKT_FLAG_KEY is never
> > set, so the patch ignores it there, the data_offset set by the code in
> > util.c is wrong, so this code overrides it, and the most annoying
> > thing: a keyframe most likely is split over multiple ogg pages, so
> > this code just returns the start of the last page read by the last
> > get_packet as start offset for the keyframe - this means we might
> > actually end up a few frames before the key frame (in theory up to 255),
> > if the encoded frames are very small.
> Hmm, I still get artifacts when seeking in Theora video, for example
> with the samples from mphq...

Update: While this does not help when seeking Theora video, OGM files
show improved seeking behavior.

Reimar, are you still working on this issue?


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