[Ffmpeg-devel] Bug when decoding WMV HD file. The aspect ratio is not preserved

[Kostya]

On Sat, Jan 27, 2007 at 02:01:00AM +0100, Michael Niedermayer wrote:
> Hi
> 
> On Wed, Jan 24, 2007 at 07:45:24PM +0100, Thomas Parmegiani wrote:
> > Hi all!
> > 
> > I downloaded some WMV HD files on :
> > 
> > http://www.microsoft.com/windows/windowsmedia/musicandvideo/hdvideo/contents
> > howcase.aspx
> > 
> > I wanted to convert it to MPEG2 without audio (Audio is WMAPro which is not
> > currently supported by ffmpeg).
> > For 720p files, converted MPEG2 files preserve aspect ratio (16/9).
> > But for 1080p files (which have a resolution of 1440 x 1080), converted
> > aspect ratio is 4/3.
> > 
> > The same problem appears if I try to use VLC to play WMV file
> > 
> > Problem seen with files :
> > 
> > Amazing caves :
> > http://download.microsoft.com/download/0/9/d/09d051c4-decc-4d39-9c57-f520187
> > 213a1/Amazing_Caves_1080.exe
> > 
> > Coral Reef :
> > http://download.microsoft.com/download/a/9/3/a9327df4-aeb5-46de-b438-d0f60da
> > 6fb54/Coral_Reef_Adventure_1080.exe
> > 
> > And I think with all others 1440 x 1080 files...
> 
> i guess the problem is in vc1.c, it doesnt export the aspect ratio ...

I will commit patch for exporting aspect ratio but it won't solve this problem.

As standard says (note in Appendix I chapter 4.2):
"When sample aspect ratio information is not present (i.e. ASPECT_RATIO_FLAG = 0
or for Simple and Main profile), the sample aspect ratio is undefined and
application-dependent".

All mentioned samples are coded as WMV3 - i.o.w. VC-1 Main profile, so aspect ratio
should be stored in container. BTW, newer MPlayer reads aspect ratio correctly.
 
> kostya?
> 
> [...]
> 
> -- 
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> 
> Republics decline into democracies and democracies degenerate into
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