[FFmpeg-devel] [PATCH] better detection of available streams for flv

[Reimar Döffinger]

On Sun, Apr 13, 2008 at 09:19:40PM +0200, Michael Niedermayer wrote:
> On Sun, Apr 13, 2008 at 09:04:52PM +0200, Reimar D?ffinger wrote:
> > On Sun, Apr 13, 2008 at 07:57:44PM +0200, Michael Niedermayer wrote:
> > > On Sun, Apr 13, 2008 at 06:06:00PM +0200, Reimar D?ffinger wrote:
> > > > Hello,
> > > > with e.g. http://eurovision.tv/upload/video/2008/WELCOMETOBELGRADE.flv
> > > > the flv demuxer thinks that there is no video stream.
> > > > Attached code changes the code to create a audio/video stream if the
> > > > metadata-parsing code finds a key starting with "audio" or "video" and
> > > > there is not yet such a stream.
> > > > Obviously, there are many other ways to do this, and if such a change is
> > > > done the hack in flv_read_header should probably be removed.
> > > > Instead of checking for any key starting with audio/video this could of
> > > > course be restricted to those we actually handle, namely audiocodecid,
> > > > videocodecid, audiosamplesize, audiosamplerate and stereo.
> > > 
> > > We support flv with invalid headers since r10887. Which does not depend on
> > > metadata. Why does this not suffice?
> > 
> > I think you mean the hack in flv_read_header?
> 
> no i mean:
> 
>     if(i == s->nb_streams){
>         av_log(NULL, AV_LOG_ERROR, "invalid stream\n");
>         st= create_stream(s, is_audio);
>     }
> 
> that is if this packet belongs to a stream which we dont have create it.

I have no idea how this is supposed to work even remotely, the metadata
that contains the codec id etc. is long past and has been ignored.
It might also not work well if the second stream starts rather late in
the file, I doubt all lavf users can handle a stream appearing during
playback well.
It would be possible to use this code (and at the same time get rid of a
lot of extra checks in amf_parse_object) if the codec info etc. would
first be stored in the context and then used in create_stream to fill
the info appropriately.
Not sure if it is really much better.

Greetings,
Reimar D?ffinger