[libcamera-devel] [PATCH v3 4/5] android: camera_device: Use YUV post-processor

[Jacopo Mondi]

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>
Reviewed-by: Umang Jain <umang.jain at ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 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 bfe61cf715c8..0be6114e3c2c 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 as 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. */
-- 
2.35.1