[FFmpeg-devel] [RFC][PATCH] Windows Television (WTV) file system handling

[Aurelien Jacobs]

On Tue, Jan 11, 2011 at 11:06:11PM +1100, Peter Ross wrote:
> On Mon, Jan 10, 2011 at 10:23:56PM +0100, Aurelien Jacobs wrote:
> > On Mon, Jan 10, 2011 at 08:30:33PM +1100, Peter Ross wrote:
> > > On Sun, Jan 09, 2011 at 11:39:00PM +0100, Aurelien Jacobs wrote:
> > > > On Sun, Jan 09, 2011 at 05:21:20PM +1100, Peter Ross wrote:
> > > > > Hi,
> > > > > 
> > > > > The Windows Television (WTV) file format is a more complex beast than
> > > > > initially imagined.
> > > > > 
> > > > > [...]
> > > > > 
> > > > > * Meta data is parsed. While it is able to extract a thumbnail image, I
> > > > >   have ifdef'd this out, as ffmpeg forbids image attachments using 
> > > > >   AVMEDIA_TYPE_ATTACHMENT.
> > > > 
> > > > I'm not sure what you are talking about here. I don't know what ffmpeg
> > > > forbids, but image attachments seems to work fine with this sample file:
> > > > http://samples.mplayerhq.hu/Matroska/ticket-a_aac.mkv
> > > 
> > > My mistake. It is ffprobe that reports codec id mismatch error, e.g.
> > > 
> > > ---
> > > [matroska,webm @ 0x8be4fd0] max_analyze_duration reached
> > > [matroska,webm @ 0x8be4fd0] Estimating duration from bitrate, this may be inaccurate
> > > Input #0, matroska,webm, from 'ticket-a_aac.mkv':
> > >   Metadata:
> > >     title           : Un ticket pour l'espace
> > >   Duration: 00:00:50.00, start: 0.000000, bitrate: N/A
> > >     Chapter #0.0: start 0.000000, end 50.006000
> > >     Metadata:
> > >       title           : 01. G?n?rique de d?but
> > >     Stream #0.0(fre): Video: h264, yuv420p, 688x288, PAR 36:37 DAR 86:37, 25 fps, 25 tbr, 1k tbn, 50 tbc
> > >     Stream #0.1(fre): Audio: aac, 48000 Hz, 5.1, s16
> > >     Stream #0.2: Attachment: mjpeg
> > >     Metadata:
> > >       filename        : Affiche du film.jpg
> > >     Stream #0.3: Attachment: mjpeg
> > >     Metadata:
> > >       filename        : Cover DVD HD.jpg
> > >     Stream #0.4: Attachment: [0][0][0][0] / 0x0000
> > >     Metadata:
> > >       filename        : tm.ttf
> > > [mjpeg @ 0x8beca20] codec type or id mismatches
> > > Error while opening codec for input stream 2
> > > [mjpeg @ 0x8c1e310] codec type or id mismatches
> > > Error while opening codec for input stream 3
> > 
> > This don't have much to do with the demuxer and is not a good reason to
> > disable the code in the demuxer.
> 
> One more thing. When attachments are present in mkv/wtv, the
> 'max_analyze_duration reached' warning is displayed. This occurs because
> AVFormatContext->codec_info_nb_frames defaults to 6 or 7. av_find_stream_info()
> expects to find as many frames in the attachment stream, and eventually
> gives up, because mkv/wtv attachments have zero frames.

Are you sure about this ? This warning requires st->codec_info_nb_frames>1
to be triggered, which should never happen with attachment stream containing
zero frame.
At least with ticket-a_aac.mkv this warning seems to be triggered by
stream 1 (aac audio).

Aurel