libcamera: simple: Fill stride and frameSize at config validation

Fill the stride and frameSize fields of the StreamConfiguration at
configuration validation time instead of at camera configuration time.
This allows applications to get the stride when trying a configuration
without modifying the active configuration of the camera.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

src/libcamera/pipeline/simple/converter.cpp

@@ -261,4 +261,19 @@ void SimpleConverter::outputBufferReady(FrameBuffer *buffer)
 	}
 }
 
+std::tuple<unsigned int, unsigned int>
+SimpleConverter::strideAndFrameSize(const Size &size,
+				    const PixelFormat &pixelFormat)
+{
+	V4L2DeviceFormat format = {};
+	format.fourcc = m2m_->capture()->toV4L2PixelFormat(pixelFormat);
+	format.size = size;
+
+	int ret = m2m_->capture()->tryFormat(&format);
+	if (ret < 0)
+		return { 0, 0 };
+
+	return { format.planes[0].bpl, format.planes[0].size };
+}
+
 } /* namespace libcamera */

src/libcamera/pipeline/simple/converter.h

@@ -10,6 +10,7 @@
 
 #include <memory>
 #include <queue>
+#include <tuple>
 #include <vector>
 
 #include <libcamera/pixel_format.h>
@@ -46,6 +47,9 @@ public:
 
 	int queueBuffers(FrameBuffer *input, FrameBuffer *output);
 
+	std::tuple<unsigned int, unsigned int>
+	strideAndFrameSize(const Size &size, const PixelFormat &pixelFormat);
+
 	Signal<FrameBuffer *, FrameBuffer *> bufferReady;
 
 private:

src/libcamera/pipeline/simple/simple.cpp

@@ -457,6 +457,30 @@ CameraConfiguration::Status SimpleCameraConfiguration::validate()
 
 	cfg.bufferCount = 3;
 
+	/* Set the stride and frameSize. */
+	if (!needConversion_) {
+		V4L2DeviceFormat format = {};
+		format.fourcc = data_->video_->toV4L2PixelFormat(cfg.pixelFormat);
+		format.size = cfg.size;
+
+		int ret = data_->video_->tryFormat(&format);
+		if (ret < 0)
+			return Invalid;
+
+		cfg.stride = format.planes[0].bpl;
+		cfg.frameSize = format.planes[0].size;
+
+		return status;
+	}
+
+	SimplePipelineHandler *pipe = static_cast<SimplePipelineHandler *>(data_->pipe_);
+	SimpleConverter *converter = pipe->converter();
+
+	std::tie(cfg.stride, cfg.frameSize) =
+		converter->strideAndFrameSize(cfg.size, cfg.pixelFormat);
+	if (cfg.stride == 0)
+		return Invalid;
+
 	return status;
 }
 
@@ -557,8 +581,6 @@ int SimplePipelineHandler::configure(Camera *camera, CameraConfiguration *c)
 		return -EINVAL;
 	}
 
-	cfg.stride = captureFormat.planes[0].bpl;
-
 	/* Configure the converter if required. */
 	useConverter_ = config->needConversion();