[FFmpeg-devel] [FFmpeg-cvslog] avfilter: add vmafmotion filter

Ronald S. Bultje rsbultje at gmail.com
Sat Oct 7 18:39:40 EEST 2017


On Sat, Oct 7, 2017 at 6:25 AM, Michael Niedermayer <michael at niedermayer.cc>

> On Sat, Oct 07, 2017 at 12:12:15PM +0200, Michael Niedermayer wrote:
> > > >>>>> On Fri, Oct 06, 2017 at 10:03:16AM -0400, Ronald S. Bultje wrote:
> > > >>>>>> I'm open to any alternative method you suggest.

> > About a solution, I didnt write alot about solutions as iam really fine
> > with any solution. There are many possible solutions ...
> > The libavfilter/af_astats.c filter i mentioned outputs statistics
> > via metadata

> > There are other possibilities. Also Hendriks suggestion about
> > turning metadata via some other application option into a file sounds
> > pretty good to me

psnr/ssim/vmafmotion indeed use per-frame metadata, but that unfortunately
doesn't address the use case of using ffmpeg to quickly dump some per-frame
stats to a file (or stdout) for quick comparison/verification (e.g. compare
against Netflix' vmaf code reference scores) since we don't print frame
metadata anywhere.

If someone does what Hendrik suggests (turning metadata into a file or into
a log) then indeed there is no problem.

> > or av_log as 2 alternatives to direct file write.

av_log would be simpler, yes.

yet another solution (if people dislike all suggestions so far) would
> be adding a flag to filters which are safe to use with untrusted
> parameters. Or a flag to options which are unsafe so they are blocked
> from being set from an untrusted input string

I actually considered this myself, but didn't want to propose it because I
personally thought it was a little hacky... I'm not against it, though.

Of these, I probably like the first one best (having some way of writing
per-frame metadata generically to stdout or to a file, without explicit
options), but it may also be the most complex one. Any takers to implement


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