[libcamera-devel] [PATCH 2/3] libcamera: ipu3: Report sensor timestamp

[Laurent Pinchart]

Hi Jacopo,

Thank you for the patch.

On Wed, Apr 07, 2021 at 06:06:43PM +0200, Jacopo Mondi wrote:
> Report the sensor's timestamp in the Request metadata by using the
> CIO2 buffer timestamp as a good-enough approximation.

s/a good-enough/an initial/

The \todo comment below shows that we'll need a better implementation,
but it can wait.

> The buffer's timestamp is recorded at DMA-transfer time, and it does not
> theoretically matches the 'start of exposure' definition, but when used
> to compare two consecutive frames it gives an acceptable estimation of
> the sensor frame period duration.
> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> ---
>  src/libcamera/pipeline/ipu3/ipu3.cpp | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> index 519cad4f8148..d52e24f847a2 100644
> --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> @@ -1251,6 +1251,15 @@ void IPU3CameraData::cio2BufferReady(FrameBuffer *buffer)
>  
>  	Request *request = info->request;
>  
> +	/*
> +	 * Record the sensor's timestamp in the request metadata.
> +	 *
> +	 * \todo The sensor timestamp should be better estimated by connecting
> +	 * to the V4L2Device::frameStart signal.
> +	 */
> +	request->metadata().set(controls::SensorTimestamp,
> +				buffer->metadata().timestamp);
> +
>  	/* If the buffer is cancelled force a complete of the whole request. */
>  	if (buffer->metadata().status == FrameMetadata::FrameCancelled) {
>  		for (auto it : request->buffers())

-- 
Regards,

Laurent Pinchart