[FFmpeg-devel] [PATCH] avdevice/v4l2: add limited support for multiplanar API

[Ramiro Polla]

On Tue, Jun 25, 2024 at 11:19 AM Anton Khirnov <anton at khirnov.net> wrote:
> Quoting Ramiro Polla (2024-06-20 17:40:39)
> > This commit adds support for V4L2's multiplanar API, but only when the
> > number of planes is 1.
> >
> > Adding full support for the multiplanar API would require a device that
> > actually uses more than 1 plane, which I have not found yet.
>
> Out of curiosity, what's the point of a multiplanar API when the plane
> count is always one?

Good question, and I wish I knew the answer. Some SBCs are providing
HDMI input through v4l2, and they decided to use the multiplanar API,
even though the count is always one.

I couldn't find many examples on how to use this API correctly, with a
couple of implementations being buggy to a point where they will only
work when the count is one.

I wish I could find a device that uses the multiplanar API and
actually provides more than one buffer so that I could properly test,
but by looking at the kernel source code I couldn't find a device that
I could easily obtain yet.