[FFmpeg-devel] rectification filter

Clément Bœsch u at pkh.me
Mon Aug 11 17:39:31 CEST 2014


On Mon, Aug 11, 2014 at 05:33:10PM +0200, Daniel Oberhoff wrote:
> 
> Am 11.08.2014 um 00:20 schrieb Michael Niedermayer <michaelni at gmx.at>:
> 
> > On Sun, Aug 10, 2014 at 08:36:37PM +0200, Daniel Oberhoff wrote:
> >> 
> >> 
> >> Von meinem iPhone gesendet
> >> 
> >>> Am 10.08.2014 um 17:50 schrieb Michael Niedermayer <michaelni at gmx.at>:
> >>> 
> >>>> On Sun, Aug 10, 2014 at 03:36:04PM +0200, Nicolas George wrote:
> >>>> Le tridi 23 thermidor, an CCXXII, Paul B Mahol a écrit :
> >>>>> It is not mandatory(but it would be nice) to add other methods to have
> >>>>> this filter included into libavfilter.
> >>>> 
> >>>> Is it really a good idea? We would end up with various interpolation /
> >>>> anti-aliasing algorithms implemented in each filter that needs it, none of
> >>>> them with the same set of architecture optimizations and each with its own
> >>>> set of bugs and misfeatures.
> >>> 
> >>>> Until someone comes up with a really satisfactory solution, I believe the
> >>>> simple solution of suggesting users to upscale before the filter and
> >>>> downscale after, using the optimized lswr scalers, is better.
> >>> 
> >>> thats not practical
> >>> a 1024x768 image would need to be upscaled to 262144x196608 to get
> >>> 8bit precission from a nearest neighbor resampler as basis
> >>> 
> >>> also see vf_perspective.c which supports bilinear and bicubic
> >>> interpolation, these surely could be shared and exist already.
> >>> 
> >>> of course we could push it with just nearest neighbor and work on that
> >>> later, but i dont think only nearest neighbor and leaving it at that
> >>> is a reasonable choice, its too poor quality wise
> >> 
> >> I would like to push now, and try to generate a refactoring patch possibly within the week. 
> > 
> > sure, feel free to push and send a pull request, or if you prefer
> > i can allso apply the patch if you post the latest verision
> 
> I am not sure about pull requests (would have to read up on how to do that properly) so rigjht now I would prefer it by patch:
> 
> 
> 
> Is that ok?
> 

Yes, please just re-submit the patch here.

Sorry about the suggestion of adding FATE tests, I forgot the fact that
the filter was actually using floats.

> Best and thanks!
> 
> Daniel

-- 
Clément B.
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