libcamera: pipeline: simple: converter: Decouple input and output completion

The SimpleConverter API signals completion of input and output buffer
pairs. This unnecessarily delays requeueing the input buffer to the
video capture queue until the output buffer completes, and also delays
signalling request completion until the input buffer completes. While
this shouldn't cause large delays in practice, it will also not scale
when multi-stream support will be added to the converter class.

To address the current issue and prepare for the future, decouple
signalling of input and output buffers completion.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Phi-Bang Nguyen <pnguyen@baylibre.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

1 files changed, 4 insertions, 7 deletions

diff --git a/src/libcamera/pipeline/simple/converter.h b/src/libcamera/pipeline/simple/converter.h
index 6e3df553..be6844ca 100644
--- a/src/libcamera/pipeline/simple/converter.h
+++ b/src/libcamera/pipeline/simple/converter.h
@@ -9,7 +9,6 @@
 #define __LIBCAMERA_PIPELINE_SIMPLE_CONVERTER_H__
 
 #include <memory>
-#include <queue>
 #include <tuple>
 #include <vector>
 
@@ -48,17 +47,15 @@ public:
 
 	int queueBuffers(FrameBuffer *input, FrameBuffer *output);
 
-	Signal<FrameBuffer *, FrameBuffer *> bufferReady;
+	Signal<FrameBuffer *> inputBufferReady;
+	Signal<FrameBuffer *> outputBufferReady;
 
 private:
-	void captureBufferReady(FrameBuffer *buffer);
-	void outputBufferReady(FrameBuffer *buffer);
+	void m2mInputBufferReady(FrameBuffer *buffer);
+	void m2mOutputBufferReady(FrameBuffer *buffer);
 
 	std::unique_ptr<V4L2M2MDevice> m2m_;
 
-	std::queue<FrameBuffer *> captureDoneQueue_;
-	std::queue<FrameBuffer *> outputDoneQueue_;
-
 	unsigned int inputBufferCount_;
 	unsigned int outputBufferCount_;
 };