[theora] Poor encoding quality with etheora and aspect ratio
Ribamar Santarosa de Sousa
ribamar.santarosa at gmail.com
Sat Mar 8 23:00:14 PST 2008
can you test the version in http://svn.xiph.org/experimental/ribamar/etheora/ ?
The final resolution (Fr) shown by the mplayer output is the video
frame resolution (fr) multiplied by the Aspect ratio (Ar):
Fr = fr * Ar. This should be the 16:9 or 4:3 final visual you probably
expected to see shown by the mplayer output. Etheora was doing:
Ar = fr, what led to problems. Now etheora does:
Ar = Fr / fr, which I expect to led to the correct values, but I may
have missed any test. Can you see (and report) if now it's working?
Thanks for bug reporting.
On Fri, Feb 29, 2008 at 3:44 PM, Manuel Dahmen <manuel.dahmen at gmail.com> wrote:
> On Fri, 29 Feb 2008 09:55:22 -0800
> Ralph Giles <giles at xiph.org> wrote:
> > On 29-Feb-08, at 2:19 AM, Manuel Dahmen wrote:
> > > And when I play the movie with mplayer or totem, the video
> > > resolution is changed from 640x480 to 854x480 (when i use
> > > ETHEORA_ASPECT_NORMAL in etheora_enc_setup).
> > This is a bug in etheora. It's passing the frame aspect ratio where
> > libtheora expects the pixel aspect ratio, which is why it looks
> > stretched.
> > For 640x480 computer-sourced video like processing produces, the
> > pixels are square anyway, but ETHEORA_ASPECT_PRESERVE is
> > unfortunately also wrong (it sets a square frame aspect ratio). So
> > you'll just have to wait until the bug is fixed.
> > (if you want to hack it, change the default aspect_numerator and
> > aspect_denominator in etheora.c to 1 and use ASPECT_PRESERVE.)
> > -r
> Thank you, -r.
> I'll take a look at etheora.c and try to find a solution.
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> Manuel Dahmen
> theora mailing list
> theora at xiph.org
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