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From: Ramiro Polla <ramiro.polla@gmail.com>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH] avdevice/v4l2: add limited support for multiplanar API
Date: Tue, 25 Jun 2024 13:56:11 +0200
Message-ID: <CALweWgC-OxLvq2kUHD6Az=u5breXUyoGj1oAQPA3A6ioEBe-qA@mail.gmail.com> (raw)
In-Reply-To: <171930716007.21847.17203985111155622112@lain.khirnov.net>

On Tue, Jun 25, 2024 at 11:19 AM Anton Khirnov <anton@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.
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  reply	other threads:[~2024-06-25 11:56 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-20 15:40 Ramiro Polla
2024-06-25  9:19 ` Anton Khirnov
2024-06-25 11:56   ` Ramiro Polla [this message]
2024-06-27 14:13     ` Ramiro Polla
2024-06-27 16:05       ` Anton Khirnov
2024-06-28 11:47         ` Ramiro Polla
2024-07-01 14:15           ` Anton Khirnov
2024-06-28 12:54       ` Ramiro Polla
2024-07-01 17:38         ` Ramiro Polla

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