Camera: Avoid latency accumulation when syncing preview to vsync
Currently if the capture intervals deviate from vsync intervals by more
than 5%, reset the captureToPresent offset. This could be problematic
when the camera capture intervals switches frequently between within 5%
threshold and outside 5% thread, because each time we reset the offset,
it could increase resulting in the overall latency become larger
and larger.
- Distinguish between fixed FPS and variable FPS
- For fixed FPS, if the frame duration is roughly aligned with display
refresh rate, use the current logic by enforcing a minimum frame
interval.
- For variable FPS, or fixed FPS deviating from display refresh rate,
simply find the closest timestamp in the vsync timeline.
- If we fail to find a presentation timestamp larger than the
previous frame, manually increase one vsync interval so that we don't
drop frame.
Test: Visually observe GoogleCamera 30/60/variable-fps video preview
Test: Visually observe OpenCamera photo and video preview,
Test: Camera CTS, PerformanceTest#testPreviewJitter*
Bug: 245629333
Change-Id: I4529b4fb5d2d5efd2dc8acf64f74412fbcafd67f
diff --git a/services/camera/libcameraservice/device3/Camera3OutputStream.h b/services/camera/libcameraservice/device3/Camera3OutputStream.h
index 3587af4..1b4739c 100644
--- a/services/camera/libcameraservice/device3/Camera3OutputStream.h
+++ b/services/camera/libcameraservice/device3/Camera3OutputStream.h
@@ -247,9 +247,10 @@
virtual status_t setBatchSize(size_t batchSize = 1) override;
/**
- * Notify the stream on change of min frame durations.
+ * Notify the stream on change of min frame durations or variable/fixed
+ * frame rate.
*/
- virtual void onMinDurationChanged(nsecs_t duration) override;
+ virtual void onMinDurationChanged(nsecs_t duration, bool fixedFps) override;
/**
* Apply ZSL related consumer usage quirk.
@@ -419,6 +420,7 @@
// Re-space frames by overriding timestamp to align with display Vsync.
// Default is on for SurfaceView bound streams.
+ bool mFixedFps = false;
nsecs_t mMinExpectedDuration = 0;
bool mSyncToDisplay = false;
DisplayEventReceiver mDisplayEventReceiver;