[FFmpeg-devel] [PATCH] [RFC] Add option for writing detailed filtergraph information to file or stdout

[Soft Works]

> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> Nicolas George
> Sent: Thursday, 26 August 2021 09:34
> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH] [RFC] Add option for writing
> detailed filtergraph information to file or stdout
> 
> Soft Works (12021-08-26):
> > This is a more complete and more flexible alternative to the
> recently submitted
> > patch "fftools: add -lavfi_dump option"
> >
> https://patchwork.ffmpeg.org/project/ffmpeg/patch/20210823094504.1007
> 89-2-george at nsup.org/
> >
> > I'm tagging this patch as 'RFC'. There's no need to tell that this
> is duplicating
> > code from ffprobe. It does, because that's the most efficient way
> for the code to
> > live at my side (unaffected and safe from regressions by upstream
> changes).
> >
> > Should it be considered for merging into main, it will likely make
> sense to merge
> > and or re-use ffprobe output writers.
> >
> > The key benefits of this implementation are:
> >
> > - Other than graph2dot and other means for printing filter graphs,
> this is
> >   outputting:
> >   - all graphs with runtime state
> >     (including auto-inserted filters)
> >   - each graph with its inputs and outputs
> >   - all filters with their in- and output pads
> >   - all connections between all input- and output pads
> >   - for each connection:
> >     - the runtime-negotiated format and media type
> >     - the hw context
> >     - if video hw context, both: hw pixfmt + sw pixfmt
> > - Output can either be printed to stdout or written to specified
> file
> > - Output is machine-readable
> > - Can output in all the same formats like ffprobe (default,
> compact, flat,
> >   ini, json, xml)
> 
> What is the practical purpose of this feature?

The purpose is to get a precise and detailed view of the filtergraphs
at runtime including all connections with their negotiated formats and 
media types.

sw