[FFmpeg-devel] [patch] pixel vs aspect ratio behaviour

Michael Niedermayer michaelni
Wed May 28 05:21:53 CEST 2008

On Wed, May 28, 2008 at 04:07:10AM +0100, vmrsss wrote:
> On 28 May 2008, at 00:35, Michael Niedermayer wrote:
> > On Sat, May 24, 2008 at 02:01:53AM +0100, vmrsss wrote:
> >> Hello.
> >>
> >> 	I think ffmpeg could be improved re the subject. Currently ffmpeg
> >> preserves (display) *aspect* ratio when resampling, and this is  
> >> indeed
> >> extremely reasonable. However, it does so also when cropping and/or
> >> padding, and this is the wrong behaviour: cropping and padding should
> >> preserve the *pixel* ratio, and not the *aspect*. Because by cropping
> >> (padding) one typically wants to chop away (extend) parts of the  
> >> frame, not
> >> to change shapes in it (exactly as when scaling one typically wants  
> >> to
> >> change the frame size, not shapes).
> >>
> >> (Incidentally: the current incarnation of avfilter always preserves  
> >> the
> >> pixel aspect ratio, also in the case of scale=....)
> >
> > Code which will be replaced by avfilter will be rejected unless its  
> > a security
> > fix.
> Clearly one wouldn't embark in any major enterprise concerning code  
> destined to go, but would an elementary bug-fix exercise like this not  
> be useful even if avfilter is not farther away than just a few months?  

Sure, find someone willing to spend the time reviewing the code, i have
better things to do than review code which will likely be droped later.

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Old school: Use the lowest level language in which you can solve the problem
New school: Use the highest level language in which the latest supercomputer
            can solve the problem without the user falling asleep waiting.
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