[libcamera-devel] [PATCH v2 4/6] fixup! android: camera_device: Compute frame durations

[Jacopo Mondi]

---
 src/android/camera_device.cpp | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index e3d43bea4700..5a8072a8a007 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -768,6 +768,26 @@ const camera_metadata_t *CameraDevice::getStaticMetadata()
 		minFrameDurationUsec = frameDurationsInfo->second.min().get<int64_t>();
 		maxFrameDurationUsec = frameDurationsInfo->second.max().get<int64_t>();
 
+		/*
+		 * Adjust the minimum frame duration to comply with Android
+		 * requirements. The camera service mandates all preview/record
+		 * streams to have a minimum frame duration < 33,366 milliseconds
+		 * (see MAX_PREVIEW_RECORD_DURATION_NS in the camera service
+		 * implementation).
+		 *
+		 * If we're close enough (+- 500 useconds) to that value round
+		 * the minimum frame duration of the camera to an accepted
+		 * value.
+		 */
+		static constexpr double MIN_PREVIEW_RECORD_FPS = 29.97;
+		static constexpr int64_t MAX_PREVIEW_RECORD_DURATION_US = 1e6 / MIN_PREVIEW_RECORD_FPS;
+		if (minFrameDurationUsec > MAX_PREVIEW_RECORD_DURATION_US) {
+			double frameDurationDelta = minFrameDurationUsec -
+						    MAX_PREVIEW_RECORD_DURATION_US;
+			if (frameDurationDelta < 500)
+				minFrameDurationUsec = MAX_PREVIEW_RECORD_DURATION_US - 1;
+		}
+
 		/*
 		 * The AE routine frame rate limits are computed using the frame
 		 * duration limits, as libcamera clips the AE routine to the
-- 
2.30.0