[libcamera-devel] [PATCH 9/9] android: Elevate min duration to 30 FPS if it's lower within 2%

[Han-Lin Chen]

It's notice that Chrome Camera App filters out the resolutions which cannot
achieve 30 FPS. Elevate the minimum frame duration to 30 FPS if FPS is lower
within 2%.

Signed-off-by: Han-Lin Chen <hanlinchen at chromium.org>
---
 src/android/camera_capabilities.cpp | 31 +++++++++++++++++++----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/src/android/camera_capabilities.cpp b/src/android/camera_capabilities.cpp
index 55d651f3..e10ab036 100644
--- a/src/android/camera_capabilities.cpp
+++ b/src/android/camera_capabilities.cpp
@@ -655,7 +655,9 @@ int CameraCapabilities::initializeStreamConfigurations()
 			int64_t maxFrameDuration = frameDurations->second.max().get<int64_t>() * 1000;
 
 			/*
-			 * Cap min frame duration to 30 FPS with 1% tolerance.
+			 * Cap min frame duration to 30 FPS with 1% tolerance,
+			 * and elevate min frame duration to 30 FPS with 2%
+			 * tolerance.
 			 *
 			 * 30 frames per second has been validated as the most
 			 * opportune frame rate for quality tuning, and power
@@ -675,17 +677,24 @@ int CameraCapabilities::initializeStreamConfigurations()
 			 * to the in-development configuration API rework.
 			 */
 			int64_t minFrameDurationCap = 1e9 / 30.0;
-			if (minFrameDuration < minFrameDurationCap) {
-				float tolerance =
-					(minFrameDurationCap - minFrameDuration) * 100.0 / minFrameDurationCap;
+			float tolerance =
+				(minFrameDurationCap - minFrameDuration) * 100.0 / minFrameDurationCap;
 
-				/*
-				 * If the tolerance is less than 1%, do not cap
-				 * the frame duration.
-				 */
-				if (tolerance > 1.0)
-					minFrameDuration = minFrameDurationCap;
-			}
+			/*
+			 * If the tolerance is less than 1%, do not cap
+			 * the frame duration.
+			 */
+			if (tolerance > 1.0)
+				minFrameDuration = minFrameDurationCap;
+
+			/*
+			 * Some applications, ex: Chrome Camera App filters out
+			 * the resolutions which cannot achieve 30 FPS. Elevate
+			 * the minimum frame duration to 30 FPS if FPS is lower
+			 * within 2%.
+			 */
+			if (tolerance < 0 && tolerance > -2.0)
+				minFrameDuration = minFrameDurationCap;
 
 			streamConfigurations_.push_back({
 				res, androidFormat, minFrameDuration, maxFrameDuration,
-- 
2.35.0.263.gb82422642f-goog