[libcamera-devel] [PATCH 2/2] pipeline: raspberrypi: Choose bit depth and packing according to raw stream

[David Plowman]

When a raw stream is specified, the bit depth and packing requested
should influence our choice of camera mode to match (if possible).

Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
---
 .../pipeline/raspberrypi/raspberrypi.cpp      | 33 ++++++++++---------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 045725dd..03012e89 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -49,6 +49,8 @@ LOG_DEFINE_CATEGORY(RPI)
 
 namespace {
 
+unsigned int DEFAULT_RAW_BIT_DEPTH = 12;
+
 /* Map of mbus codes to supported sizes reported by the sensor. */
 using SensorFormats = std::map<unsigned int, std::vector<Size>>;
 
@@ -125,15 +127,13 @@ double scoreFormat(double desired, double actual)
 	return score;
 }
 
-V4L2SubdeviceFormat findBestFormat(const SensorFormats &formatsMap, const Size &req)
+V4L2SubdeviceFormat findBestFormat(const SensorFormats &formatsMap, const Size &req, unsigned int bitDepth)
 {
 	double bestScore = std::numeric_limits<double>::max(), score;
 	V4L2SubdeviceFormat bestFormat;
 
 #define PENALTY_AR		1500.0
-#define PENALTY_8BIT		2000.0
-#define PENALTY_10BIT		1000.0
-#define PENALTY_12BIT		   0.0
+#define PENALTY_BIT_DEPTH	500.0
 
 	/* Calculate the closest/best mode from the user requested size. */
 	for (const auto &iter : formatsMap) {
@@ -152,12 +152,7 @@ V4L2SubdeviceFormat findBestFormat(const SensorFormats &formatsMap, const Size &
 			score += PENALTY_AR * scoreFormat(reqAr, fmtAr);
 
 			/* Add any penalties... this is not an exact science! */
-			if (info.bitsPerPixel == 12)
-				score += PENALTY_12BIT;
-			else if (info.bitsPerPixel == 10)
-				score += PENALTY_10BIT;
-			else if (info.bitsPerPixel == 8)
-				score += PENALTY_8BIT;
+			score += abs(info.bitsPerPixel - bitDepth) * PENALTY_BIT_DEPTH;
 
 			if (score <= bestScore) {
 				bestScore = score;
@@ -397,9 +392,14 @@ CameraConfiguration::Status RPiCameraConfiguration::validate()
 			 * Calculate the best sensor mode we can use based on
 			 * the user request.
 			 */
-			V4L2SubdeviceFormat sensorFormat = findBestFormat(data_->sensorFormats_, cfg.size);
+			const PixelFormatInfo &info = PixelFormatInfo::info(cfg.pixelFormat);
+			unsigned int bitDepth = info.isValid() ? info.bitsPerPixel : DEFAULT_RAW_BIT_DEPTH;
+			V4L2SubdeviceFormat sensorFormat = findBestFormat(data_->sensorFormats_, cfg.size, bitDepth);
+			BayerFormat::Packing packing = BayerFormat::Packing::CSI2;
+			if (info.isValid() && !info.packed)
+				packing = BayerFormat::Packing::None;
 			V4L2DeviceFormat unicamFormat = toV4L2DeviceFormat(sensorFormat,
-									   BayerFormat::Packing::CSI2);
+									   packing);
 			int ret = data_->unicam_[Unicam::Image].dev()->tryFormat(&unicamFormat);
 			if (ret)
 				return Invalid;
@@ -533,7 +533,7 @@ CameraConfiguration *PipelineHandlerRPi::generateConfiguration(Camera *camera,
 		switch (role) {
 		case StreamRole::Raw:
 			size = data->sensor_->resolution();
-			sensorFormat = findBestFormat(data->sensorFormats_, size);
+			sensorFormat = findBestFormat(data->sensorFormats_, size, DEFAULT_RAW_BIT_DEPTH);
 			pixelFormat = mbusCodeToPixelFormat(sensorFormat.mbus_code,
 							    BayerFormat::Packing::CSI2);
 			ASSERT(pixelFormat.isValid());
@@ -622,6 +622,7 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 	Size maxSize, sensorSize;
 	unsigned int maxIndex = 0;
 	bool rawStream = false;
+	unsigned int bitDepth = DEFAULT_RAW_BIT_DEPTH;
 
 	/*
 	 * Look for the RAW stream (if given) size as well as the largest
@@ -638,7 +639,9 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 			sensorSize = cfg.size;
 			rawStream = true;
 			/* Check if the user has explicitly set an unpacked format. */
-			packing = BayerFormat::fromPixelFormat(cfg.pixelFormat).packing;
+			BayerFormat bayerFormat = BayerFormat::fromPixelFormat(cfg.pixelFormat);
+			packing = bayerFormat.packing;
+			bitDepth = bayerFormat.bitDepth;
 		} else {
 			if (cfg.size > maxSize) {
 				maxSize = config->at(i).size;
@@ -664,7 +667,7 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 	}
 
 	/* First calculate the best sensor mode we can use based on the user request. */
-	V4L2SubdeviceFormat sensorFormat = findBestFormat(data->sensorFormats_, rawStream ? sensorSize : maxSize);
+	V4L2SubdeviceFormat sensorFormat = findBestFormat(data->sensorFormats_, rawStream ? sensorSize : maxSize, bitDepth);
 	ret = data->sensor_->setFormat(&sensorFormat);
 	if (ret)
 		return ret;
-- 
2.30.2