[PATCH 5/5] pipeline: rpi: vc4: Add wallclock timestamp support

[Kieran Bingham]

Quoting David Plowman (2024-12-06 14:27:42)
> Wallclocks are enabled for the unicam output, and the values returned
> in frame metadata are made available to the base pipeline handler
> class.
> 
> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> ---
>  src/libcamera/pipeline/rpi/vc4/vc4.cpp | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/src/libcamera/pipeline/rpi/vc4/vc4.cpp b/src/libcamera/pipeline/rpi/vc4/vc4.cpp
> index fd8d84b1..eb98c56e 100644
> --- a/src/libcamera/pipeline/rpi/vc4/vc4.cpp
> +++ b/src/libcamera/pipeline/rpi/vc4/vc4.cpp
> @@ -398,6 +398,9 @@ int PipelineHandlerVc4::platformRegister(std::unique_ptr<RPi::CameraData> &camer
>                 Camera::create(std::move(cameraData), id, streams);
>         PipelineHandler::registerCamera(std::move(camera));
>  
> +       /* Enable wall clock timestamps for the unicam output. */
> +       data->unicam_[Unicam::Image].dev()->enableWallClock(&wallClockRecoery_);
> +
>         LOG(RPI, Info) << "Registered camera " << id
>                        << " to Unicam device " << unicam->deviceNode()
>                        << " and ISP device " << isp->deviceNode();
> @@ -784,6 +787,7 @@ void Vc4CameraData::unicamBufferDequeue(FrameBuffer *buffer)
>                  * as it does not receive the FrameBuffer object.
>                  */
>                 ctrl.set(controls::SensorTimestamp, buffer->metadata().timestamp);
> +               ctrl.set(controls::FrameWallClock, buffer->metadata().wallClock);

I think the only reason to have &wallClockRecovery_ object
supplied/instantiated by the Pipeline handler was so that at this line -
instead of accessing buffer->metadata().wallclock - it would use

	ctrl.set(controls::FrameWallClock,
		 wallClockRecovery_.getOutput(buffer->metadata().timestamp));

instead.

But (Have I said this yet?) Personally I would keep this as


		ctrl.set(controls::FrameWallClock, buffer->metadata().wallClock);

and have the wallClockRecovery_ as a 'feature' provided by the
V4L2VideoDevice in a purely common way. It's not going to do anything
different on other pipeline handlers that would require customisation as
far as I can tell.

--
Kieran


>                 bayerQueue_.push({ buffer, std::move(ctrl), delayContext });
>         } else {
>                 embeddedQueue_.push(buffer);
> -- 
> 2.39.5
>