[FFmpeg-devel] [PATCH v5 00/12] Subtitle Filtering

[Hendrik Leppkes]

On Wed, Sep 15, 2021 at 9:39 AM Soft Works <softworkz at hotmail.com> wrote:
>
> In my upcoming patchset, I have added a new struct AVSubtitleArea
> which is similar to AVSubtitleRect with the difference that
>
> - It's not AVSubtitleRect (which can be deprecated then)
> - It uses refcounted buffers for the image data
>
> AVFrame gets an array of AVSubtitleArea structs. The image data
> is attached to AVSubtitleArea (data, buf, linesize).
>
> I'm not sure whether it would make sense to store the image data in
> buf/data of AVFrame like
>
> AVSubtitleArea[0] <=> buf[0], buf[1]
> AVSubtitleArea[1] <=> buf[2], buf[3]
>

I suppose the main problem is that there can be more areas then we
have buf entries?
There is just one small wrinkle, there is an expectation in various
areas of the code that an empty frame has buf[0] zero, and conversely
a filled one does not.

Perhaps we can use buf and extended_buf as needed, just so it fits
into the established paradigm? Having more then 8 areas is possible,
but not necessarily always the case.

If the presence of the buf is also the only difference to
AVSubtitleRect, there is no reason to not continue using it and moving
it to avutil, and just have AVSubtitle itself be deprecated in the
long-term.

- Hendrik