[FFmpeg-devel] [PATCH] doc/bitstream_filters: add filter_units practical examples for removing closed captions

[Marth64]

Thanks, Stefano, I agree it’s not ideal with just having magic numbers. If
I think of a creative solution I'll let you know.

Appreciate your time,

On Sun, Mar 10, 2024 at 09:56 Stefano Sabatini <stefasab at gmail.com> wrote:

> On date Saturday 2024-03-09 19:56:49 -0600, Marth64 wrote:
> > Following up on this from December 2023. I simplified the content and
> > hopefully addressed the feedback.
> >
> > Signed-off-by: Marth64 <marth64 at proxyid.net>
> > ---
> >  doc/bitstream_filters.texi | 15 +++++++++++++++
> >  1 file changed, 15 insertions(+)
> >
> > diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
> > index e06de1a73a..61539d2473 100644
> > --- a/doc/bitstream_filters.texi
> > +++ b/doc/bitstream_filters.texi
> > @@ -213,6 +213,21 @@ To remove all AUDs, SEI and filler from an H.265
> stream:
> >  ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=35|38-40'
> OUTPUT
> >  @end example
> >
> > +To remove all user data from a MPEG-2 stream, including Closed Captions:
> > + at example
> > +ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=178' OUTPUT
> > + at end example
> > +
> > +To remove all SEI from a H264 stream, including Closed Captions:
> > + at example
> > +ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=6' OUTPUT
> > + at end example
> > +
> > +To remove all prefix and suffix SEI from a HEVC stream, including
> Closed Captions and dynamic HDR:
> > + at example
> > +ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=39|40'
> OUTPUT
> > + at end example
> > +
>
> Not against, but I'm not super convinced this is super useful as it
> does not really explain what these values come from.  Probably it
> would be more useful a table, or even better make the parser somehow
> expose the supported types with the meaning (this would enable having
> e.g. a symbolic type "cc" abstracting the containter format).
>
> OTOH I agree thius would provide some practical examples, therefore
> I'll apply while we have no smarter way to expose the logic in a more
> effective way.
>
> Thanks.
>