[FFmpeg-devel] matroska file hits eof on any seek

[Reimar Döffinger]

On Fri, Feb 17, 2012 at 07:31:58PM +0100, Michael Niedermayer wrote:
> On Fri, Feb 17, 2012 at 06:51:39PM +0100, Reimar Döffinger wrote:
> > On Fri, Feb 17, 2012 at 10:34:17AM -0700, Pavel Koshevoy wrote:
> > > On 2/17/2012 10:23 AM, Reimar Döffinger wrote:
> > > >On Fri, Feb 17, 2012 at 10:20:58AM -0700, Pavel Koshevoy wrote:
> > > >>On 2/17/2012 2:45 AM, Don Moir wrote:
> > > >>>This file is probably a "bad" file.
> > > >>
> > > >>Yes, it is.  If you look at it with mkvinfo GUI you'll see that
> > > >>there are no keyframes there.
> > > >>
> > > >>You can fix it using yamkaRemux, make sure to pass the -fixKeyFlag
> > > >>option.  With this option yamkaRemux parses H.264 tracks and looks
> > > >>for IDR nal_init_type.  It uses that to fix the Matroska SimpleBlock
> > > >>keyframe flag.
> > > >Have you tested that? Because if that's the only thing
> > > >it does, it is probably the kind of application that
> > > >creates those broken files.
> > > 
> > > Yes, I downloaded the source file, remuxed with yamkaRemux, and was
> > > able to play/seek it with my ffmpeg based player.  According to
> > > mkvinfo that file was made with mkvmerge v2.7.0, not yamka.
> > 
> > I looked at the code, as far as I can tell you just got lucky.
> > It looks for an IDR slice.
> > However having an IDR slice does not tell you anything.
> > If _all_ slices are IDR slices, yes.
> 
> > If one is an IDR slice and some are not that tells you nothing.
> 
> Without checking the spec i dont think this is allowed

Hm, I thought it was, but I certainly don't know the spec by heart,
not even remotely :-)