[theora-dev] ffmpeg2theora aspect ratio

[Stefan Bender]

On 2009-12-04 01:31:15 wrote j at v2v.cc:
> On 12/03/2009 11:11 PM, Stefan Bender wrote:
> > Hi,
> > 
> > I discovered the following lines in ffmpeg2theora.c (~l.550):
> > 
> >     if ((float)this->aspect_numerator/this->aspect_denominator < 1.09) {
> >         this->aspect_numerator = 1;
> >         this->aspect_denominator = 1;
> >         frame_aspect=(float)(this->aspect_numerator*this->picture_width)/
> >                             (this->aspect_denominator*this->picture_height);
> >     }
> > 
> > This prevents the correct display of video that has an pixel
> > aspect ratio of 1.09, which is the ratio with which some dvb
> > content is delivered.
> > 
> > This code was introduced in svn revision 14125 and was
> > whitespace corrected in svn revision 15823 and my question is
> > what is the purpose of this code?
> > Or: what is expected to break if these lines are removed?
> > The encoding of dvb content, at least, works better without it.
> > 
> i had some footage where this was used.
> but i think it should be take out, will review it and take it out if i
> can not find a good reason for it to be there...

Thanks for looking into it.
I discovered you already checked it into svn. :)

FWIW, it didn't change any encoding parameters;
it just prevented e.g. mplayer to automatically scale 720x576
theora content to the correct 768x576 (for 4:3 frame aspect)
when it was encoded with ffmpeg2theora.

Thanks again,
Stefan