gstreamer: Move timestamp calculation out of pad loop

The buffer pts and the pad latency are computed from the framebuffer
timestamp, separately for each pad. Use the sensor timestamp provided
through the request metadata instead, to compute the values once outside
of the pads loop.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>

1 files changed, 24 insertions, 10 deletions

diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
index 700bee2b..37f201e8 100644
--- a/src/gstreamer/gstlibcamerasrc.cpp
+++ b/src/gstreamer/gstlibcamerasrc.cpp
@@ -34,6 +34,7 @@
 
 #include <libcamera/camera.h>
 #include <libcamera/camera_manager.h>
+#include <libcamera/control_ids.h>
 
 #include <gst/base/base.h>
 
@@ -164,22 +165,35 @@ GstLibcameraSrcState::requestCompleted(Request *request)
 		return;
 	}
 
+	GstClockTime latency;
+	GstClockTime pts;
+
+	if (GST_ELEMENT_CLOCK(src_)) {
+		int64_t timestamp = request->metadata().get(controls::SensorTimestamp);
+
+		GstClockTime gst_base_time = GST_ELEMENT(src_)->base_time;
+		GstClockTime gst_now = gst_clock_get_time(GST_ELEMENT_CLOCK(src_));
+		/* \todo Need to expose which reference clock the timestamp relates to. */
+		GstClockTime sys_now = g_get_monotonic_time() * 1000;
+
+		/* Deduced from: sys_now - sys_base_time == gst_now - gst_base_time */
+		GstClockTime sys_base_time = sys_now - (gst_now - gst_base_time);
+		pts = timestamp - sys_base_time;
+		latency = sys_now - timestamp;
+	} else {
+		latency = 0;
+		pts = GST_CLOCK_TIME_NONE;
+	}
+
 	for (GstPad *srcpad : srcpads_) {
 		Stream *stream = gst_libcamera_pad_get_stream(srcpad);
 		GstBuffer *buffer = wrap->detachBuffer(stream);
 
 		FrameBuffer *fb = gst_libcamera_buffer_get_frame_buffer(buffer);
 
-		if (GST_ELEMENT_CLOCK(src_)) {
-			GstClockTime gst_base_time = GST_ELEMENT(src_)->base_time;
-			GstClockTime gst_now = gst_clock_get_time(GST_ELEMENT_CLOCK(src_));
-			/* \todo Need to expose which reference clock the timestamp relates to. */
-			GstClockTime sys_now = g_get_monotonic_time() * 1000;
-
-			/* Deduced from: sys_now - sys_base_time == gst_now - gst_base_time */
-			GstClockTime sys_base_time = sys_now - (gst_now - gst_base_time);
-			GST_BUFFER_PTS(buffer) = fb->metadata().timestamp - sys_base_time;
-			gst_libcamera_pad_set_latency(srcpad, sys_now - fb->metadata().timestamp);
+		if (GST_CLOCK_TIME_IS_VALID(pts)) {
+			GST_BUFFER_PTS(buffer) = pts;
+			gst_libcamera_pad_set_latency(srcpad, latency);
 		} else {
 			GST_BUFFER_PTS(buffer) = 0;
 		}