[libcamera-devel] [PATCH v3 13/16] libcamera: raspberry: Report sensor timestamp

[Jacopo Mondi]

Report the sensor's timestamp in the Request metadata by using the
Unicam::Image buffer timestamp as an initial approximation.

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.

Reviewed-by: Naushir Patuck <naush at raspberrypi.com>
Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/libcamera/pipeline/raspberrypi/raspberrypi.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 6c6d31f78c88..ac135f95de12 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -1414,6 +1414,18 @@ void RPiCameraData::unicamBufferDequeue(FrameBuffer *buffer)
 			<< ", timestamp: " << buffer->metadata().timestamp;
 
 	if (stream == &unicam_[Unicam::Image]) {
+		/*
+		 * Record the sensor timestamp in the Request.
+		 *
+		 * \todo Do not assume the request in the front of the queue
+		 * is the correct one
+		 */
+		Request *request = requestQueue_.front();
+		ASSERT(request);
+
+		request->metadata().set(controls::SensorTimestamp,
+					buffer->metadata().timestamp);
+
 		/*
 		 * Lookup the sensor controls used for this frame sequence from
 		 * DelayedControl and queue them along with the frame buffer.
-- 
2.31.1