[libcamera-devel] [PATCH 18/20] libcamera: pipeline: simple: Support configuration of multiple streams

[Laurent Pinchart]

Extend the SimpleCameraConfiguration to support multiple streams, using
the multi-stream capability of the SimpleConverter class. Wiring up
multi-stream support in the other pipeline handler operations will come
in further commits.

To keep the code simple, require all streams to use the converter if any
stream needs it. It would be possible to generate one stream without
conversion (provided the format and size match what the capture device
can generate), and this is left as a future optimization.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/libcamera/pipeline/simple/simple.cpp | 174 ++++++++++++++---------
 1 file changed, 104 insertions(+), 70 deletions(-)

diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
index c987e1a0d9cb..58e5f0d23139 100644
--- a/src/libcamera/pipeline/simple/simple.cpp
+++ b/src/libcamera/pipeline/simple/simple.cpp
@@ -538,62 +538,94 @@ CameraConfiguration::Status SimpleCameraConfiguration::validate()
 	}
 
 	/* Cap the number of entries to the available streams. */
-	if (config_.size() > 1) {
-		config_.resize(1);
+	if (config_.size() > data_->streams_.size()) {
+		config_.resize(data_->streams_.size());
 		status = Adjusted;
 	}
 
-	StreamConfiguration &cfg = config_[0];
-
-	/* Adjust the pixel format. */
-	auto it = data_->formats_.find(cfg.pixelFormat);
-	if (it == data_->formats_.end())
-		it = data_->formats_.begin();
-
-	PixelFormat pixelFormat = it->first;
-	if (cfg.pixelFormat != pixelFormat) {
-		LOG(SimplePipeline, Debug) << "Adjusting pixel format";
-		cfg.pixelFormat = pixelFormat;
-		status = Adjusted;
-	}
-
-	pipeConfig_ = it->second;
-	if (!pipeConfig_->outputSizes.contains(cfg.size)) {
-		LOG(SimplePipeline, Debug)
-			<< "Adjusting size from " << cfg.size.toString()
-			<< " to " << pipeConfig_->captureSize.toString();
-		cfg.size = pipeConfig_->captureSize;
-		status = Adjusted;
-	}
-
-	needConversion_ = cfg.pixelFormat != pipeConfig_->captureFormat
-			|| cfg.size != pipeConfig_->captureSize;
-
-	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;
+	/*
+	 * Pick a configuration for the pipeline based on the pixel format for
+	 * the streams (ordered from highest to lowest priority). Default to
+	 * the first pipeline configuration if no streams requests a supported
+	 * pixel format.
+	 */
+	pipeConfig_ = data_->formats_.begin()->second;
+
+	for (const StreamConfiguration &cfg : config_) {
+		auto it = data_->formats_.find(cfg.pixelFormat);
+		if (it != data_->formats_.end()) {
+			pipeConfig_ = it->second;
+			break;
+		}
 	}
 
+	/* Adjust the requested streams. */
 	SimplePipelineHandler *pipe = static_cast<SimplePipelineHandler *>(data_->pipe_);
 	SimpleConverter *converter = pipe->converter();
 
-	std::tie(cfg.stride, cfg.frameSize) =
-		converter->strideAndFrameSize(cfg.pixelFormat, cfg.size);
-	if (cfg.stride == 0)
-		return Invalid;
+	/*
+	 * Enable usage of the converter when producing multiple streams, as
+	 * the video capture device can't capture to multiple buffers.
+	 *
+	 * It is possible to produce up to one stream without conversion
+	 * (provided the format and size match), at the expense of more complex
+	 * buffer handling (including allocation of internal buffers to be used
+	 * when a request doesn't contain a buffer for the stream that doesn't
+	 * require any conversion, similar to raw capture use cases). This is
+	 * left as a future improvement.
+	 */
+	needConversion_ = config_.size() > 1;
+
+	for (unsigned int i = 0; i < config_.size(); ++i) {
+		StreamConfiguration &cfg = config_[i];
+
+		/* Adjust the pixel format and size. */
+		auto it = std::find(pipeConfig_->outputFormats.begin(),
+				    pipeConfig_->outputFormats.end(),
+				    cfg.pixelFormat);
+		if (it == pipeConfig_->outputFormats.end())
+			it = pipeConfig_->outputFormats.begin();
+
+		PixelFormat pixelFormat = *it;
+		if (cfg.pixelFormat != pixelFormat) {
+			LOG(SimplePipeline, Debug) << "Adjusting pixel format";
+			cfg.pixelFormat = pixelFormat;
+			status = Adjusted;
+		}
+
+		if (!pipeConfig_->outputSizes.contains(cfg.size)) {
+			LOG(SimplePipeline, Debug)
+				<< "Adjusting size from " << cfg.size.toString()
+				<< " to " << pipeConfig_->captureSize.toString();
+			cfg.size = pipeConfig_->captureSize;
+			status = Adjusted;
+		}
+
+		if (cfg.pixelFormat != pipeConfig_->captureFormat ||
+		    cfg.size != pipeConfig_->captureSize)
+			needConversion_ = true;
+
+		/* Set the stride, frameSize and bufferCount. */
+		if (needConversion_) {
+			std::tie(cfg.stride, cfg.frameSize) =
+				converter->strideAndFrameSize(cfg.pixelFormat, cfg.size);
+			if (cfg.stride == 0)
+				return Invalid;
+		} else {
+			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;
+		}
+
+		cfg.bufferCount = 3;
+	}
 
 	return status;
 }
@@ -628,16 +660,18 @@ CameraConfiguration *SimplePipelineHandler::generateConfiguration(Camera *camera
 		       });
 
 	/*
-	 * Create the stream configuration. Take the first entry in the formats
+	 * Create the stream configurations. Take the first entry in the formats
 	 * map as the default, for lack of a better option.
 	 *
 	 * \todo Implement a better way to pick the default format
 	 */
-	StreamConfiguration cfg{ StreamFormats{ formats } };
-	cfg.pixelFormat = formats.begin()->first;
-	cfg.size = formats.begin()->second[0].max;
+	for ([[maybe_unused]] StreamRole role : roles) {
+		StreamConfiguration cfg{ StreamFormats{ formats } };
+		cfg.pixelFormat = formats.begin()->first;
+		cfg.size = formats.begin()->second[0].max;
 
-	config->addConfiguration(cfg);
+		config->addConfiguration(cfg);
+	}
 
 	config->validate();
 
@@ -650,7 +684,6 @@ int SimplePipelineHandler::configure(Camera *camera, CameraConfiguration *c)
 		static_cast<SimpleCameraConfiguration *>(c);
 	SimpleCameraData *data = cameraData(camera);
 	V4L2VideoDevice *video = data->video_;
-	StreamConfiguration &cfg = config->at(0);
 	int ret;
 
 	/*
@@ -694,28 +727,29 @@ int SimplePipelineHandler::configure(Camera *camera, CameraConfiguration *c)
 		return -EINVAL;
 	}
 
-	/* Configure the converter if required. */
+	/* Configure the converter if needed. */
+	std::vector<std::reference_wrapper<StreamConfiguration>> outputCfgs;
 	data->useConverter_ = config->needConversion();
-	if (data->useConverter_) {
-		StreamConfiguration inputCfg;
-		inputCfg.pixelFormat = pipeConfig->captureFormat;
-		inputCfg.size = pipeConfig->captureSize;
-		inputCfg.stride = captureFormat.planes[0].bpl;
-		inputCfg.bufferCount = kNumInternalBuffers;
 
-		ret = converter_->configure(inputCfg, { cfg });
-		if (ret < 0) {
-			LOG(SimplePipeline, Error)
-				<< "Unable to configure converter";
-			return ret;
-		}
+	for (unsigned int i = 0; i < config->size(); ++i) {
+		StreamConfiguration &cfg = config->at(i);
 
-		LOG(SimplePipeline, Debug) << "Using format converter";
+		cfg.setStream(&data->streams_[i]);
+
+		if (data->useConverter_)
+			outputCfgs.push_back(cfg);
 	}
 
-	cfg.setStream(&data->streams_[0]);
+	if (outputCfgs.empty())
+		return 0;
 
-	return 0;
+	StreamConfiguration inputCfg;
+	inputCfg.pixelFormat = pipeConfig->captureFormat;
+	inputCfg.size = pipeConfig->captureSize;
+	inputCfg.stride = captureFormat.planes[0].bpl;
+	inputCfg.bufferCount = kNumInternalBuffers;
+
+	return converter_->configure(inputCfg, outputCfgs);
 }
 
 int SimplePipelineHandler::exportFrameBuffers(Camera *camera, Stream *stream,
-- 
Regards,

Laurent Pinchart