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/Camera3OfflineSession.h b/services/camera/libcameraservice/device3/Camera3OfflineSession.h
index a799719..5ee6ca5 100644
--- a/services/camera/libcameraservice/device3/Camera3OfflineSession.h
+++ b/services/camera/libcameraservice/device3/Camera3OfflineSession.h
@@ -248,6 +248,9 @@
// The current minimum expected frame duration based on AE_TARGET_FPS_RANGE
nsecs_t mMinExpectedDuration = 0;
+ // Whether the camera device runs at fixed frame rate based on AE_MODE and
+ // AE_TARGET_FPS_RANGE
+ bool mIsFixedFps = false;
// SetErrorInterface
void setErrorState(const char *fmt, ...) override;