[libcamera-devel] [PATCH v2 4/5] android: camera_device: Use YUV post-processor

[Paul Elder]

From: Hirokazu Honda <hiroh at chromium.org>

When creating the list of StreamConfiguration to be requested to the camera,
map NV12 streams of equal size and format together, so that they will be
generated by using the YUV post-processor.

Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/android/camera_device.cpp | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index 95c14f60..9ee34b93 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -605,14 +605,40 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
 			continue;
 		}
 
+		/*
+		 * While gralloc usage flags are supposed to report usage
+		 * patterns to select a suitable buffer allocation strategy, in
+		 * practice they're also used to make other decisions, such as
+		 * selecting the actual format for the IMPLEMENTATION_DEFINED
+		 * HAL pixel format. To avoid issues, we thus have to set the
+		 * GRALLOC_USAGE_HW_CAMERA_WRITE flag unconditionally, even for
+		 * streams that will be produced in software.
+		 */
+		stream->usage |= GRALLOC_USAGE_HW_CAMERA_WRITE;
+
+		/*
+		 * If a CameraStream with the same size and format of the
+		 * current stream has already been requested, associate the two.
+		 */
+		auto iter = std::find_if(
+			streamConfigs.begin(), streamConfigs.end(),
+			[&size, &format](const Camera3StreamConfig &streamConfig) {
+				return streamConfig.config.size == size &&
+				       streamConfig.config.pixelFormat == format;
+			});
+		if (iter != streamConfigs.end()) {
+			/* Add usage to copy the buffer in streams[0] to stream. */
+			iter->streams[0].stream->usage |= GRALLOC_USAGE_SW_READ_OFTEN;
+			stream->usage |= GRALLOC_USAGE_SW_WRITE_OFTEN;
+			iter->streams.push_back({ stream, CameraStream::Type::Mapped });
+			continue;
+		}
+
 		Camera3StreamConfig streamConfig;
 		streamConfig.streams = { { stream, CameraStream::Type::Direct } };
 		streamConfig.config.size = size;
 		streamConfig.config.pixelFormat = format;
 		streamConfigs.push_back(std::move(streamConfig));
-
-		/* This stream will be produced by hardware. */
-		stream->usage |= GRALLOC_USAGE_HW_CAMERA_WRITE;
 	}
 
 	/* Now handle the MJPEG streams, adding a new stream if required. */
-- 
2.30.2