[FFmpeg-devel] [PATCH] lavfi: add a libplacebo filter

[Nicolas George]

Niklas Haas (12021-03-09):
> From: Niklas Haas <git at haasn.xyz>
> 
> This filter conceptually maps the libplacebo `pl_renderer` API into
> libavfilter, which is a high-level image rendering API designed to work
> with an RGB pipeline internally. As such, there's no way to avoid e.g.
> chroma interpolation with this filter, although new versions of
> libplacebo support outputting back to subsampled YCbCr after processing
> is done.
> 
> That being said, `pl_renderer` supports automatic integration of the
> majority of libplacebo's shaders, ranging from debanding to tone
> mapping, and also supports loading custom mpv-style user shaders, making
> this API a natural candidate for getting a lot of functionality out of
> relatively little code.
> 
> In the future, I may approach this problem either by rewriting this
> filter to also support a non-renderer codepath, or by upgrading
> libplacebo's renderer to support a full YCbCr pipeline.
> 
> It's worth noting that this filter could be extended in the future to
> support HWframes frames of type AV_PIX_FMT_VULKAN, but this is not
> currently possible due to API limitations in the vulkan hwaccel.
> (Although it's also worth pointing out that, apart from a single
> `pl_vulkan_create` call, the current `vf_libplacebo` code does not
> depend on vulkan at all - so in theory it could be extended to support
> OpenGL or other libplacebo backends)
> ---
>  configure                   |   3 +
>  libavfilter/Makefile        |   1 +
>  libavfilter/allfilters.c    |   1 +
>  libavfilter/vf_libplacebo.c | 627 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 632 insertions(+)
>  create mode 100644 libavfilter/vf_libplacebo.c

Thanks for the patch. I have not yet looked at the code itself.

Please include some documentation, it would be helpful even for
reviewing.

Regards,

-- 
  Nicolas George
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