[libcamera-devel] [PATCH 3/8] cam: Use SensorTimestamp rather than buffer metadata

[Kieran Bingham]

The SensorTimestamp is defined to be the time of capture of the image.
While all streams should have the same timestamp, this is not always
defined or guaranteed as ISP drivers may not forward sequence numbers
and timestamps from their input buffer.

Use the Request metadata to get the SensorTimestamp which must be
set by the pipeline handlers according to the data from the capture
device.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 src/cam/camera_session.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/cam/camera_session.cpp b/src/cam/camera_session.cpp
index 1bf460fa3fb7..50170723c30f 100644
--- a/src/cam/camera_session.cpp
+++ b/src/cam/camera_session.cpp
@@ -359,10 +359,11 @@ void CameraSession::processRequest(Request *request)
 	const Request::BufferMap &buffers = request->buffers();
 
 	/*
-	 * Compute the frame rate. The timestamp is arbitrarily retrieved from
-	 * the first buffer, as all buffers should have matching timestamps.
+	 * Compute the frame rate. The timestamp is retrieved from the
+	 * SensorTimestamp property, though all streams should have the
+	 * same timestamp.
 	 */
-	uint64_t ts = buffers.begin()->second->metadata().timestamp;
+	uint64_t ts = request->metadata().get(controls::SensorTimestamp);
 	double fps = ts - last_;
 	fps = last_ != 0 && fps ? 1000000000.0 / fps : 0.0;
 	last_ = ts;
-- 
2.30.2