From: Tomasz Figa <tfiga@chromium.org>
To: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Hans Verkuil <hverkuil-cisco@xs4all.nl>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Nicolas Dufresne <nicolas@ndufresne.ca>
Subject: Re: [PATCH] v4l: Add source change event for colorimetry
Date: Tue, 13 Oct 2020 15:40:56 +0200 [thread overview]
Message-ID: <CAAFQd5AYvMrZQtZ2UBOEG6Nar06bZrRZdE57Y6N7+6dZxJ0m_A@mail.gmail.com> (raw)
In-Reply-To: <d11da037-92e5-2ee7-8723-10162d16eba9@linaro.org>
On Tue, Oct 13, 2020 at 11:03 AM Stanimir Varbanov
<stanimir.varbanov@linaro.org> wrote:
>
> Hi,
>
> On 7/2/20 2:52 PM, Stanimir Varbanov wrote:
> > Hi,
> >
> > Once we have this event there is still open question how the client will
> > know the data buffer on which the new colorspace is valid/applied.
> >
> > The options could be:
> > * a new buffer flag and
> > * some information in the v4l2_event structure.
> >
> > Thoughts?
>
> Kindly ping.
>
The event itself sounds good to me, but how do we know which buffer is
the first to have the new colorimetry?
Best regards,
Tomasz
> >
> > On 7/2/20 1:00 PM, Stanimir Varbanov wrote:
> >> This event indicate that the source colorspace is changed
> >> during run-time. The client has to retrieve the new colorspace
> >> identifiers by getting the format (G_FMT).
> >>
> >> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
> >> ---
> >> .../userspace-api/media/v4l/vidioc-dqevent.rst | 11 ++++++++++-
> >> .../userspace-api/media/videodev2.h.rst.exceptions | 1 +
> >> include/uapi/linux/videodev2.h | 1 +
> >> 3 files changed, 12 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst b/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
> >> index a9a176d5256d..3f69c753db58 100644
> >> --- a/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
> >> +++ b/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
> >> @@ -381,7 +381,16 @@ call.
> >> that many Video Capture devices are not able to recover from a temporary
> >> loss of signal and so restarting streaming I/O is required in order for
> >> the hardware to synchronize to the video signal.
> >> -
> >> + * - ``V4L2_EVENT_SRC_CH_COLORIMETRY``
> >> + - 0x0002
> >> + - This event gets triggered when a colorspace change is detected at
> >> + an input. By colorspace change here we include also changes in the
> >> + colorspace specifiers (transfer function, Y'CbCr encoding and
> >> + quantization). This event can come from an input or from video decoder.
> >> + Once the event has been send to the client the driver has to update
> >> + the colorspace specifiers internally so that they could be retrieved by
> >> + client. In that case queue re-negotiation is not needed as this change
> >> + only reflects on the interpretation of the data.
> >>
> >> Return Value
> >> ============
> >> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> >> index ca05e4e126b2..54fc21af852d 100644
> >> --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> >> +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> >> @@ -492,6 +492,7 @@ replace define V4L2_EVENT_CTRL_CH_FLAGS ctrl-changes-flags
> >> replace define V4L2_EVENT_CTRL_CH_RANGE ctrl-changes-flags
> >>
> >> replace define V4L2_EVENT_SRC_CH_RESOLUTION src-changes-flags
> >> +replace define V4L2_EVENT_SRC_CH_COLORIMETRY src-changes-flags
> >>
> >> replace define V4L2_EVENT_MD_FL_HAVE_FRAME_SEQ :c:type:`v4l2_event_motion_det`
> >>
> >> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> >> index 303805438814..b5838bc4e3a3 100644
> >> --- a/include/uapi/linux/videodev2.h
> >> +++ b/include/uapi/linux/videodev2.h
> >> @@ -2351,6 +2351,7 @@ struct v4l2_event_frame_sync {
> >> };
> >>
> >> #define V4L2_EVENT_SRC_CH_RESOLUTION (1 << 0)
> >> +#define V4L2_EVENT_SRC_CH_COLORIMETRY (1 << 1)
> >>
> >> struct v4l2_event_src_change {
> >> __u32 changes;
> >>
> >
>
> --
> regards,
> Stan
next prev parent reply other threads:[~2020-10-13 13:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-02 10:00 [PATCH] v4l: Add source change event for colorimetry Stanimir Varbanov
2020-07-02 11:52 ` Stanimir Varbanov
2020-10-13 9:02 ` Stanimir Varbanov
2020-10-13 13:40 ` Tomasz Figa [this message]
2020-10-13 13:53 ` Stanimir Varbanov
2020-10-13 14:07 ` Tomasz Figa
2020-10-13 14:53 ` Stanimir Varbanov
2020-10-13 14:56 ` Tomasz Figa
2020-11-03 10:30 ` Hans Verkuil
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAAFQd5AYvMrZQtZ2UBOEG6Nar06bZrRZdE57Y6N7+6dZxJ0m_A@mail.gmail.com \
--to=tfiga@chromium.org \
--cc=hverkuil-cisco@xs4all.nl \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=mchehab@kernel.org \
--cc=nicolas@ndufresne.ca \
--cc=stanimir.varbanov@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).