[FFmpeg-devel] [PATCH 2/5] fftools/cmdutils: Print filter input/output formats in help output

[Soft Works]

> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> Soft Works
> Sent: Wednesday, October 13, 2021 9:36 AM
> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH 2/5] fftools/cmdutils: Print
> filter input/output formats in help output
> 
> 
> 
> > -----Original Message-----
> > From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> > Paul B Mahol
> > Sent: Wednesday, October 13, 2021 9:27 AM
> > To: FFmpeg development discussions and patches <ffmpeg-
> > devel at ffmpeg.org>
> > Subject: Re: [FFmpeg-devel] [PATCH 2/5] fftools/cmdutils: Print
> > filter input/output formats in help output
> >
> > scale, extractplanes, alphaextract, waveform, vectorscope.
> 
> See the results below. Nothing is flawed. Of course there can't be an
> output in all cases, as you have pointed out correctly.
> 
> But for the remaining 95% of filters, the formats output is very
> useful.
> (and correct)

I'd also like to point out that this information is currently completely
inaccessible for anybody without looking it up in the source code.

Knowing about a filter's supported formats is important for building
efficient filter chains and avoiding unexpected auto format 
conversions.

I had added this output years ago and the information (which is 
parsed from the help output) is an important prerequisite for our 
automated filter-string-building (outside of ffmpeg).

I also use it regularly for looking up filter formats and I think
it might be useful for others as well.

Kind regards,
softworkz