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

Diego Biurrun diego
Sun Jul 6 14:10:14 CEST 2008


On Thu, Jun 26, 2008 at 12:35:45PM +0200, Michael Niedermayer wrote:
> 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...
> 
> I can confirm this, it doesnt work here either

So who knows how to fix this? :)

Diego




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