[FFmpeg-devel] [PATCH] avfilter/vf_showinfo: use av_frame_side_data_name() to print side data names

[James Almer]

On 1/13/2023 11:38 AM, Jan Ekström wrote:
> On Wed, Jan 11, 2023 at 9:31 PM James Almer <jamrial at gmail.com> wrote:
>>
>> This ensures all defined types are supported, even if only to report
>> their presence and print their size if a custom implementation is
>> not added.
>>
>> Signed-off-by: James Almer <jamrial at gmail.com>
>> ---
>> This patch supersedes:
>> [PATCH 1/2] avfilter/vf_showinfo: remove superfluous line break
>> [PATCH 2/2] avfilter/vf_showinfo: add support for raw Dolby Vision RPU side data
>>
>> By achieving the same effect in a future proof, generic way.
>>
> 
> I quite like this approach, and agree with the idea. It did feel weird
> that we have a single location which sets human readable names for
> side data types, yet it was not utilized.
> 
> I think the only drawback is that I'm pretty sure there would be some
> side data types printed out now with a different name, and I do know
> that some people parse the output of this filter instead of utilizing
> ffprobe. Granted, we generally don't promise that log lines are a
> machine readable interface. Thus this is not a blocker, but something
> to keep in mind.

ffprobe is what we provide for parseable output. Also muxers like 
framehash, which are versioned and such. So yeah, av_log() output is not 
something we promise will be unchanged.

> 
> I wonder if at some point (at the latest when we'll start wanting to
> make a generic string/dict based side data setting interface) we'll
> want to have separately a "long name" (more human readable) as well as
> a shorter identifier similar to AVCodecs' "name".
> 
> Jan

Pushed.