LCamDev: implement configureSessionModeCReq

We can, theoretically, now change the v4l camera's mode.

commonLibs/lcameraDev/planarYuvFormatPolicy.cpp

@@ -0,0 +1,146 @@
+#include <planarYuvFormatPolicy.h>
+#include <libcamera/formats.h>
+#include <sstream>
+#include <stdexcept>
+
+namespace lcamera_dev {
+
+namespace {
+
+using libcamera::formats::NV12;
+using libcamera::formats::NV16;
+using libcamera::formats::NV21;
+using libcamera::formats::NV24;
+using libcamera::formats::NV42;
+using libcamera::formats::NV61;
+using libcamera::formats::UYVY;
+using libcamera::formats::VYUY;
+using libcamera::formats::YUYV;
+using libcamera::formats::YUV420;
+using libcamera::formats::YUV422;
+using libcamera::formats::YUV444;
+using libcamera::formats::YVU420;
+using libcamera::formats::YVU422;
+using libcamera::formats::YVU444;
+using libcamera::formats::YVYU;
+
+bool pixelFormatMatches(
+	const libcamera::PixelFormat& pixelFormat,
+	const libcamera::PixelFormat& expectedFormat)
+{
+	return pixelFormat == expectedFormat;
+}
+
+bool isFullyPlanarYuvFourcc(const libcamera::PixelFormat& pixelFormat)
+{
+	return pixelFormatMatches(pixelFormat, YUV420)
+		|| pixelFormatMatches(pixelFormat, YVU420)
+		|| pixelFormatMatches(pixelFormat, YUV422)
+		|| pixelFormatMatches(pixelFormat, YVU422)
+		|| pixelFormatMatches(pixelFormat, YUV444)
+		|| pixelFormatMatches(pixelFormat, YVU444);
+}
+
+bool isSemiPlanarYuvFourcc(const libcamera::PixelFormat& pixelFormat)
+{
+	return pixelFormatMatches(pixelFormat, NV12)
+		|| pixelFormatMatches(pixelFormat, NV21)
+		|| pixelFormatMatches(pixelFormat, NV16)
+		|| pixelFormatMatches(pixelFormat, NV61)
+		|| pixelFormatMatches(pixelFormat, NV24)
+		|| pixelFormatMatches(pixelFormat, NV42);
+}
+
+bool isPackedYuvFourcc(const libcamera::PixelFormat& pixelFormat)
+{
+	return pixelFormatMatches(pixelFormat, YUYV)
+		|| pixelFormatMatches(pixelFormat, YVYU)
+		|| pixelFormatMatches(pixelFormat, UYVY)
+		|| pixelFormatMatches(pixelFormat, VYUY);
+}
+
+} // namespace
+
+bool isFullyPlanarYuv(const libcamera::PixelFormat& pixelFormat)
+{
+	return isFullyPlanarYuvFourcc(pixelFormat);
+}
+
+bool isKnownYuvCaptureFormat(const libcamera::PixelFormat& pixelFormat)
+{
+	return isFullyPlanarYuvFourcc(pixelFormat)
+		|| isSemiPlanarYuvFourcc(pixelFormat)
+		|| isPackedYuvFourcc(pixelFormat);
+}
+
+unsigned yuvCapturePlaneCount(const libcamera::PixelFormat& pixelFormat)
+{
+	if (isFullyPlanarYuvFourcc(pixelFormat)) {
+		return 3;
+	}
+
+	if (isSemiPlanarYuvFourcc(pixelFormat)) {
+		return 2;
+	}
+
+	if (isPackedYuvFourcc(pixelFormat)) {
+		return 1;
+	}
+
+	return 0;
+}
+
+std::string formatCandidateListForDiagnostics(
+	const std::vector<libcamera::PixelFormat>& candidates)
+{
+	std::ostringstream stream;
+	for (std::size_t i = 0; i < candidates.size(); ++i)
+	{
+		if (i > 0) {
+			stream << ", ";
+		}
+
+		stream << candidates[i].toString();
+	}
+
+	return stream.str();
+}
+
+std::optional<libcamera::PixelFormat>
+selectYuvCaptureFormat(
+	const std::vector<libcamera::PixelFormat>& candidates,
+	bool fullPlanarIsOptional)
+{
+	if (candidates.empty())
+	{
+		throw std::runtime_error(
+			"lcameraDev: no YUV pixel-format candidates available");
+	}
+
+	if (!fullPlanarIsOptional)
+	{
+		for (const libcamera::PixelFormat& candidate : candidates)
+		{
+			if (isFullyPlanarYuv(candidate)) {
+				return candidate;
+			}
+		}
+
+		throw std::runtime_error(
+			"lcameraDev: no fully planar YUV format among candidates: "
+			+ formatCandidateListForDiagnostics(candidates));
+	}
+
+	for (const libcamera::PixelFormat& candidate : candidates)
+	{
+		if (isKnownYuvCaptureFormat(candidate)) {
+			return candidate;
+		}
+	}
+
+	throw std::runtime_error(
+		"lcameraDev: no known YUV capture format among candidates: "
+		+ formatCandidateListForDiagnostics(candidates));
+}
+
+} // namespace lcamera_dev