[Ffmpeg-devel] Broken rv20 sample

[Michael Niedermayer]

Hi

On Sat, Sep 30, 2006 at 02:20:33AM +0200, Roberto Togni wrote:
> On Sat, 30 Sep 2006 00:41:35 +0200
> Michael Niedermayer <michaelni at gmx.at> wrote:
> 
> > Hi
> > 
> > On Fri, Sep 29, 2006 at 10:53:00PM +0200, Roberto Togni wrote:
> > > Hi all
> > > 
> > > RV20 video from this stream
> > > rtsp://ert.media.noc.ntua.gr:5554/encoder/tv.rm can't be played by
> > > ffmpeg decoder (latest svn). A sample clip (dumped with MPlayer) can be
> > > found at http://samples.mplayerhq.hu/real/VC-RV20/rv20errors.rm
> > > 
> > > The file works ok with the binary codec.
> > 
> > and it also works fine if you force the w/h to 256x208
> > 
> > just wondering where thats hidden
> > 
> 
> hmm, there is some extra-extradata that is passed by MPlayer real
> demuxer to vd_realvid, 

lavf passes that too


> and that is used to build the data for the
> cmsg24 custom_message. This happens only for codec id (H.263 ID) is >=
> 0x20200002 and <= 0x30335652.
> This data is appended at the end of the bitmapinfoheader struct in
> MPlayer (after the 8-byte extradata) but it's not added to the biSize
> field.
> 
> This specific file has 8 extra bytes, even if MPlayer now uses only 6
> bytes (typical files have 4 or 6 bytes). The values are multiplied by 4
> before passing them to the binary codec.
> 
> In this file we have 0x40 0x34 0x2c 0x24 0xc0 0x90 0x58 0x48
> the first 2 bytes, multiplied by 4, are the picture size (i'll have to
> check if it's true also for other files).

no sadly not, ive some where the first 2 are not the correct size
and in some of them the last 2 are correct


[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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