[libcamera-devel] [PATCH 17/17] libcamera: pipeline: uvcvideo: Add format information and validation

[Niklas Söderlund]

Extend the uvcvideo pipeline with format information and validation. The
format information is gathered by enumerating the v4l2 device. This
enumeration approach is valid for UVC as it has a static and simple
media graph.

Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
---
 src/libcamera/pipeline/uvcvideo.cpp | 46 +++++++++++++++++++++++------
 1 file changed, 37 insertions(+), 9 deletions(-)

diff --git a/src/libcamera/pipeline/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo.cpp
index 45260f34c8f5daba..ce9f281891a8bc5e 100644
--- a/src/libcamera/pipeline/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo.cpp
@@ -95,18 +95,42 @@ CameraConfiguration::Status UVCCameraConfiguration::validate()
 	}
 
 	StreamConfiguration &cfg = config_[0];
+	const StreamFormats &formats = cfg.formats();
 
-	/* \todo: Validate the configuration against the device capabilities. */
 	const unsigned int pixelFormat = cfg.pixelFormat;
 	const Size size = cfg.size;
 
-	cfg.pixelFormat = V4L2_PIX_FMT_YUYV;
-	cfg.size = { 640, 480 };
+	bool found = false;
+	for (unsigned int pixfmt : formats.pixelformats()) {
+		if (pixfmt == pixelFormat) {
+			found = true;
+			break;
+		}
+	}
+	if (!found)
+		cfg.pixelFormat = formats.pixelformats().front();
 
-	if (cfg.pixelFormat != pixelFormat || cfg.size != size) {
+	if (cfg.pixelFormat != pixelFormat) {
 		LOG(UVC, Debug)
-			<< "Adjusting configuration from " << cfg.toString()
-			<< " to " << cfg.size.toString() << "-YUYV";
+			<< "Adjusting pixel format from " << pixelFormat
+			<< " to " << cfg.pixelFormat;
+		status = Adjusted;
+	}
+
+	const std::vector<Size> &formatSizes = formats.sizes(cfg.pixelFormat);
+	cfg.size = formatSizes.front();
+	for (const Size &formatsSize : formatSizes) {
+		if (formatsSize <= size)
+			cfg.size = formatsSize;
+
+		if (formatsSize == size)
+			break;
+	}
+
+	if (cfg.size != size) {
+		LOG(UVC, Debug)
+			<< "Adjusting size from " << size.toString()
+			<< " to " << cfg.size.toString();
 		status = Adjusted;
 	}
 
@@ -123,14 +147,18 @@ PipelineHandlerUVC::PipelineHandlerUVC(CameraManager *manager)
 CameraConfiguration *PipelineHandlerUVC::generateConfiguration(Camera *camera,
 	const StreamRoles &roles)
 {
+	UVCCameraData *data = cameraData(camera);
 	CameraConfiguration *config = new UVCCameraConfiguration();
 
 	if (roles.empty())
 		return config;
 
-	StreamConfiguration cfg{};
-	cfg.pixelFormat = V4L2_PIX_FMT_YUYV;
-	cfg.size = { 640, 480 };
+	V4L2DeviceFormats v4l2formats = data->video_->formats();
+	StreamFormats formats(v4l2formats.data());
+	StreamConfiguration cfg(formats);
+
+	cfg.pixelFormat = formats.pixelformats().front();
+	cfg.size = formats.sizes(cfg.pixelFormat).back();
 	cfg.bufferCount = 4;
 
 	config->addConfiguration(cfg);
-- 
2.21.0