libcamera: camera: Add support for stream usages

Instead of requesting the default configuration for a set of streams
where the application has to figure out which streams provided by the
camera is best suited for its intended usage, have the library figure
this out by using stream usages.

The application asks the library for a list of streams and a suggested
default configuration for them by supplying a list of stream usages.
Once the list is retrieved the application can fine-tune the returned
configuration and then try to apply it to the camera.

Currently no pipeline handler is prepared to handle stream usages but
nor did it make use of the list of Stream IDs which was the previous
interface. The main reason for this is that all cameras currently only
provide one stream each. This will still be the case but the API will be
prepared to expand both pipeline handlers and applications to support
streams usages.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

13 files changed, 37 insertions, 61 deletions

diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
index 77e4cd1e..0386671c 100644
--- a/include/libcamera/camera.h
+++ b/include/libcamera/camera.h
@@ -22,6 +22,7 @@ class PipelineHandler;
 class Request;
 class Stream;
 class StreamConfiguration;
+class StreamUsage;
 
 class Camera final
 {
@@ -44,7 +45,7 @@ public:
 
 	const std::set<Stream *> &streams() const;
 	std::map<Stream *, StreamConfiguration>
-	streamConfiguration(std::set<Stream *> &streams);
+	streamConfiguration(const std::vector<StreamUsage> &usage);
 	int configureStreams(std::map<Stream *, StreamConfiguration> &config);
 
 	int allocateBuffers();
diff --git a/src/cam/main.cpp b/src/cam/main.cpp
index b5895fae..d45ffd37 100644
--- a/src/cam/main.cpp
+++ b/src/cam/main.cpp
@@ -80,8 +80,7 @@ static int parseOptions(int argc, char *argv[])
 
 static int prepareCameraConfig(std::map<Stream *, StreamConfiguration> *config)
 {
-	std::set<Stream *> streams = camera->streams();
-	*config = camera->streamConfiguration(streams);
+	*config = camera->streamConfiguration({ Stream::VideoRecording() });
 	Stream *stream = config->begin()->first;
 
 	if (options.isSet(OptFormat)) {
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index 8ee9cc08..63fde0ff 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -345,33 +345,23 @@ const std::set<Stream *> &Camera::streams() const
 }
 
 /**
- * \brief Retrieve a group of stream configurations
- * \param[in] streams A map of stream IDs and configurations to setup
+ * \brief Retrieve a group of stream configurations according to stream usages
+ * \param[in] usages A list of stream usages
  *
- * Retrieve the camera's configuration for a specified group of streams. The
- * caller can specifies which of the camera's streams to retrieve configuration
- * from by populating \a streams.
+ * Retrieve configuration for a set of desired usages. The caller specifies a
+ * list of stream usages and the camera returns a map of suitable streams and
+ * their suggested default configurations.
  *
- * The easiest way to populate the array of streams to fetch configuration from
- * is to first retrieve the camera's full array of stream with streams() and
- * then potentially trim it down to only contain the streams the caller
- * are interested in.
- *
- * \return A map of successfully retrieved stream IDs and configurations or an
- * empty list on error.
+ * \return A map of streams to configurations if the requested usages can be
+ * satisfied, or an empty map otherwise
  */
 std::map<Stream *, StreamConfiguration>
-Camera::streamConfiguration(std::set<Stream *> &streams)
+Camera::streamConfiguration(const std::vector<StreamUsage> &usages)
 {
-	if (disconnected_ || !streams.size())
+	if (disconnected_ || !usages.size() || usages.size() > streams_.size())
 		return std::map<Stream *, StreamConfiguration>{};
 
-	for (Stream *stream : streams) {
-		if (streams_.find(stream) == streams_.end())
-			return std::map<Stream *, StreamConfiguration>{};
-	}
-
-	return pipe_->streamConfiguration(this, streams);
+	return pipe_->streamConfiguration(this, usages);
 }
 
 /**
diff --git a/src/libcamera/include/pipeline_handler.h b/src/libcamera/include/pipeline_handler.h
index acb376e0..8a1706fa 100644
--- a/src/libcamera/include/pipeline_handler.h
+++ b/src/libcamera/include/pipeline_handler.h
@@ -53,7 +53,7 @@ public:
 	virtual bool match(DeviceEnumerator *enumerator) = 0;
 
 	virtual std::map<Stream *, StreamConfiguration>
-	streamConfiguration(Camera *camera, std::set<Stream *> &streams) = 0;
+	streamConfiguration(Camera *camera, const std::vector<StreamUsage> &usages) = 0;
 	virtual int configureStreams(Camera *camera,
 				     std::map<Stream *, StreamConfiguration> &config) = 0;
 
diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index fed04ce5..5d01504e 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -141,7 +141,7 @@ public:
 
 	std::map<Stream *, StreamConfiguration>
 	streamConfiguration(Camera *camera,
-			    std::set<Stream *> &streams) override;
+			    const std::vector<StreamUsage> &usages) override;
 	int configureStreams(Camera *camera,
 			     std::map<Stream *, StreamConfiguration> &config) override;
 
@@ -206,7 +206,7 @@ PipelineHandlerIPU3::~PipelineHandlerIPU3()
 
 std::map<Stream *, StreamConfiguration>
 PipelineHandlerIPU3::streamConfiguration(Camera *camera,
-					 std::set<Stream *> &streams)
+					 const std::vector<StreamUsage> &usages)
 {
 	std::map<Stream *, StreamConfiguration> configs;
 	IPU3CameraData *data = cameraData(camera);
diff --git a/src/libcamera/pipeline/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo.cpp
index cc3e0cd9..dfff7116 100644
--- a/src/libcamera/pipeline/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo.cpp
@@ -28,7 +28,7 @@ public:
 
 	std::map<Stream *, StreamConfiguration>
 	streamConfiguration(Camera *camera,
-			    std::set<Stream *> &streams) override;
+			    const std::vector<StreamUsage> &usages) override;
 	int configureStreams(Camera *camera,
 			     std::map<Stream *, StreamConfiguration> &config) override;
 
@@ -84,14 +84,12 @@ PipelineHandlerUVC::~PipelineHandlerUVC()
 
 std::map<Stream *, StreamConfiguration>
 PipelineHandlerUVC::streamConfiguration(Camera *camera,
-					std::set<Stream *> &streams)
+					const std::vector<StreamUsage> &usages)
 {
 	UVCCameraData *data = cameraData(camera);
-
 	std::map<Stream *, StreamConfiguration> configs;
 	StreamConfiguration config{};
 
-	LOG(UVC, Debug) << "Retrieving default format";
 	config.width = 640;
 	config.height = 480;
 	config.pixelFormat = V4L2_PIX_FMT_YUYV;
diff --git a/src/libcamera/pipeline/vimc.cpp b/src/libcamera/pipeline/vimc.cpp
index 2e8c26fb..4da4ca01 100644
--- a/src/libcamera/pipeline/vimc.cpp
+++ b/src/libcamera/pipeline/vimc.cpp
@@ -28,7 +28,7 @@ public:
 
 	std::map<Stream *, StreamConfiguration>
 	streamConfiguration(Camera *camera,
-			    std::set<Stream *> &streams) override;
+			    const std::vector<StreamUsage> &usages) override;
 	int configureStreams(Camera *camera,
 			     std::map<Stream *, StreamConfiguration> &config) override;
 
@@ -84,14 +84,12 @@ PipelineHandlerVimc::~PipelineHandlerVimc()
 
 std::map<Stream *, StreamConfiguration>
 PipelineHandlerVimc::streamConfiguration(Camera *camera,
-					 std::set<Stream *> &streams)
+					 const std::vector<StreamUsage> &usages)
 {
 	VimcCameraData *data = cameraData(camera);
 	std::map<Stream *, StreamConfiguration> configs;
-
 	StreamConfiguration config{};
 
-	LOG(VIMC, Debug) << "Retrieving default format";
 	config.width = 640;
 	config.height = 480;
 	config.pixelFormat = V4L2_PIX_FMT_RGB24;
diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
index 1a858f26..0574f990 100644
--- a/src/libcamera/pipeline_handler.cpp
+++ b/src/libcamera/pipeline_handler.cpp
@@ -152,13 +152,13 @@ PipelineHandler::~PipelineHandler()
  * \fn PipelineHandler::streamConfiguration()
  * \brief Retrieve a group of stream configurations for a specified camera
  * \param[in] camera The camera to fetch default configuration from
- * \param[in] streams An array of streams to fetch information about
+ * \param[in] usages A list of stream usages
  *
  * Retrieve the species camera's default configuration for a specified group of
- * streams. The caller shall populate the \a streams array with the streams it
- * wish to fetch the configuration from. The map of streams and configuration
- * returned can then be examined by the caller to learn about the defualt
- * parameters for the specified streams.
+ * use-cases. The caller shall populate the \a usages array with the use-cases it
+ * wishes to fetch the default configuration for. The map of streams and
+ * configurations returned can then be examined by the caller to learn about
+ * the default parameters for the specified streams.
  *
  * The intended companion to this is \a configureStreams() which can be used to
  * change the group of streams parameters.
diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
index fea70142..faa3bc57 100644
--- a/src/qcam/main_window.cpp
+++ b/src/qcam/main_window.cpp
@@ -97,9 +97,8 @@ int MainWindow::startCapture()
 {
 	int ret;
 
-	Stream *stream = *camera_->streams().begin();
-	std::set<Stream *> streams{ stream };
-	config_ = camera_->streamConfiguration(streams);
+	config_ = camera_->streamConfiguration({ Stream::VideoRecording() });
+	Stream *stream = config_.begin()->first;
 	ret = camera_->configureStreams(config_);
 	if (ret < 0) {
 		std::cout << "Failed to configure camera" << std::endl;
diff --git a/test/camera/capture.cpp b/test/camera/capture.cpp
index f6932b75..b8dbdb62 100644
--- a/test/camera/capture.cpp
+++ b/test/camera/capture.cpp
@@ -42,10 +42,9 @@ protected:
 
 	int run()
 	{
-		Stream *stream = *camera_->streams().begin();
-		std::set<Stream *> streams = { stream };
 		std::map<Stream *, StreamConfiguration> conf =
-			camera_->streamConfiguration(streams);
+			camera_->streamConfiguration({ Stream::VideoRecording() });
+		Stream *stream = conf.begin()->first;
 		StreamConfiguration *sconf = &conf.begin()->second;
 
 		if (!configurationValid(conf)) {
diff --git a/test/camera/configuration_default.cpp b/test/camera/configuration_default.cpp
index 856cd415..09861716 100644
--- a/test/camera/configuration_default.cpp
+++ b/test/camera/configuration_default.cpp
@@ -20,14 +20,10 @@ protected:
 	{
 		std::map<Stream *, StreamConfiguration> conf;
 
-		/*
-		 * Test that asking for default configuration for a valid
-		 * array of streams returns something valid.
-		 */
-		std::set<Stream *> streams = { *camera_->streams().begin() };
-		conf = camera_->streamConfiguration(streams);
+		/* Test asking for configuration for a video stream. */
+		conf = camera_->streamConfiguration({ Stream::VideoRecording() });
 		if (conf.empty()) {
-			cout << "Failed to retrieve configuration for valid streams"
+			cout << "Failed to retrieve configuration for video streams"
 			     << endl;
 			return TestFail;
 		}
@@ -39,12 +35,11 @@ protected:
 
 		/*
 		 * Test that asking for configuration for an empty array of
-		 * streams returns an empty list of configurations.
+		 * stream usages returns an empty list of configurations.
 		 */
-		std::set<Stream *> streams_empty = {};
-		conf = camera_->streamConfiguration(streams_empty);
+		conf = camera_->streamConfiguration({});
 		if (!conf.empty()) {
-			cout << "Failed to retrieve configuration for empty streams"
+			cout << "Failed to retrieve configuration for empty usage list"
 			     << endl;
 			return TestFail;
 		}
diff --git a/test/camera/configuration_set.cpp b/test/camera/configuration_set.cpp
index cac1da95..1bc01e66 100644
--- a/test/camera/configuration_set.cpp
+++ b/test/camera/configuration_set.cpp
@@ -18,9 +18,8 @@ class ConfigurationSet : public CameraTest
 protected:
 	int run()
 	{
-		std::set<Stream *> streams = { *camera_->streams().begin() };
 		std::map<Stream *, StreamConfiguration> conf =
-			camera_->streamConfiguration(streams);
+			camera_->streamConfiguration({ Stream::VideoRecording() });
 		StreamConfiguration *sconf = &conf.begin()->second;
 
 		if (!configurationValid(conf)) {
diff --git a/test/camera/statemachine.cpp b/test/camera/statemachine.cpp
index f4395f2b..ab3c6fb5 100644
--- a/test/camera/statemachine.cpp
+++ b/test/camera/statemachine.cpp
@@ -235,9 +235,7 @@ protected:
 
 	int run()
 	{
-		Stream *stream = *camera_->streams().begin();
-		std::set<Stream *> streams = { stream };
-		defconf_ = camera_->streamConfiguration(streams);
+		defconf_ = camera_->streamConfiguration({ Stream::VideoRecording() });
 
 		if (testAvailable() != TestPass) {
 			cout << "State machine in Available state failed" << endl;