[FFmpeg-devel] [PATCH v16 15/16] avcodec/subtitles: Migrate subtitle encoders to frame-based API and provide a compatibility shim for the legacy api

[Hendrik Leppkes]

On Fri, Nov 26, 2021 at 4:09 PM Andreas Rheinhardt
<andreas.rheinhardt at outlook.com> wrote:
>
> Soft Works:
> > Also introduce deferred loading of ass headers for all cases where it can't be taken from the context of a decoder.
>
> This should be a commit of its own.
>
> >
> > Signed-off-by: softworkz <softworkz at hotmail.com>
> > ---
> >  libavcodec/assenc.c        |  81 ++++++++++++++++++++---------
> >  libavcodec/avcodec.h       |   7 +++
> >  libavcodec/dvbsubenc.c     |  85 +++++++++++++++---------------
> >  libavcodec/dvdsubenc.c     |  89 +++++++++++++++++---------------
> >  libavcodec/encode.c        |  98 ++++++++++++++++++++++++++++++++++-
> >  libavcodec/movtextenc.c    | 103 +++++++++++++++++++++++++------------
> >  libavcodec/srtenc.c        |  96 ++++++++++++++++++++++------------
> >  libavcodec/tests/avcodec.c |   2 -
> >  libavcodec/ttmlenc.c       |  82 +++++++++++++++++++++++------
> >  libavcodec/webvttenc.c     |  73 +++++++++++++++++++-------
> >  libavcodec/xsubenc.c       |  65 ++++++++++++-----------
> >  11 files changed, 541 insertions(+), 240 deletions(-)
> >
> > diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> > index 0c5819b116..304b35ba86 100644
> > --- a/libavcodec/avcodec.h
> > +++ b/libavcodec/avcodec.h
> > @@ -2949,10 +2949,17 @@ void av_parser_close(AVCodecParserContext *s);
> >   * @{
> >   */
> >
> > + /**
> > +  * @deprecated Use @ref avcodec_encode_subtitle2() instead.
> > +  */
> > +attribute_deprecated
> >  int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
> >                              const AVSubtitle *sub);
> >
> >
> > +int avcodec_encode_subtitle2(AVCodecContext* avctx, struct AVPacket* avpkt,
> > +    AVFrame* frame, int* got_packet);
> > +
>
> Missing documentation. The signature and the implementation shows that
> you have recreated the old encode API avcodec_encode_(audio2|video2)
> with the difference that you (like the current subtitle API) require
> preallocated (not necessarily refcounted) buffers in avpkt. Why not use
> the ordinary encode API?

I concur on that question. We have a generic encode/decode API without
dependency on any media type, that should be used going forward for
all media types, and not anything else being introduced now.

- Hendrik