[libcamera-devel] [PATCH v3 3/5] cam: Add support to specify multiple stream configurations with roles

[Niklas Söderlund]

Extend the cam tool to allow configuring more than one stream. Add an
optional parameter to the --stream option to specify a usage role for
the stream. The stream role is passed to libcamera to give it control
over which streams to use.

To support multiple streams, creation of requests needs to be reworked
to limit the number of requests to match the stream with the least
number of buffers. This should be improved in the future as the tool and
the library evolve.

Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/cam/main.cpp | 75 +++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 64 insertions(+), 11 deletions(-)

diff --git a/src/cam/main.cpp b/src/cam/main.cpp
index 3dd4b24d2401162c..da05612b1c347b31 100644
--- a/src/cam/main.cpp
+++ b/src/cam/main.cpp
@@ -5,8 +5,10 @@
  * main.cpp - cam - The libcamera swiss army knife
  */
 
+#include <algorithm>
 #include <iomanip>
 #include <iostream>
+#include <limits.h>
 #include <map>
 #include <signal.h>
 #include <string.h>
@@ -42,6 +44,9 @@ void signalHandler(int signal)
 static int parseOptions(int argc, char *argv[])
 {
 	KeyValueParser streamKeyValue;
+	streamKeyValue.addOption("role", OptionString,
+				 "Role for the stream (viewfinder, video, still)",
+				 ArgumentRequired);
 	streamKeyValue.addOption("width", OptionInteger, "Width in pixels",
 				 ArgumentRequired);
 	streamKeyValue.addOption("height", OptionInteger, "Height in pixels",
@@ -61,7 +66,7 @@ static int parseOptions(int argc, char *argv[])
 			 "The default file name is 'frame-#.bin'.",
 			 "file", ArgumentOptional, "filename");
 	parser.addOption(OptStream, &streamKeyValue,
-			 "Set configuration of a camera stream", "stream");
+			 "Set configuration of a camera stream", "stream", true);
 	parser.addOption(OptHelp, OptionNone, "Display this help message",
 			 "help");
 	parser.addOption(OptList, OptionNone, "List all cameras", "list");
@@ -80,11 +85,51 @@ static int parseOptions(int argc, char *argv[])
 
 static int prepareCameraConfig(CameraConfiguration *config)
 {
-	*config = camera->streamConfiguration({ Stream::VideoRecording() });
-	Stream *stream = config->front();
+	std::vector<StreamUsage> roles;
 
-	if (options.isSet(OptStream)) {
-		KeyValueParser::Options conf = options[OptStream];
+	/* If no configuration is provided assume a single video stream. */
+	if (!options.isSet(OptStream)) {
+		*config = camera->streamConfiguration({ Stream::VideoRecording() });
+		return 0;
+	}
+
+	const std::vector<OptionValue> &streamOptions =
+		options[OptStream].toArray();
+
+	/* Use roles and get a default configuration. */
+	for (auto const &value : streamOptions) {
+		KeyValueParser::Options conf = value.toKeyValues();
+
+		if (!conf.isSet("role")) {
+			roles.push_back(Stream::VideoRecording());
+		} else if (conf["role"].toString() == "viewfinder") {
+			roles.push_back(Stream::Viewfinder(conf["width"],
+							   conf["height"]));
+		} else if (conf["role"].toString() == "video") {
+			roles.push_back(Stream::VideoRecording());
+		} else if (conf["role"].toString() == "still") {
+			roles.push_back(Stream::StillCapture());
+		} else {
+			std::cerr << "Unknown stream role "
+				  << conf["role"].toString() << std::endl;
+			return -EINVAL;
+		}
+	}
+
+	*config = camera->streamConfiguration(roles);
+
+	if (!config->valid()) {
+		std::cerr << "Failed to get default stream configuration"
+			  << std::endl;
+		return -EINVAL;
+	}
+
+	/* Apply configuration explicitly requested. */
+	CameraConfiguration::iterator it = config->begin();
+	for (auto const &value : streamOptions) {
+		KeyValueParser::Options conf = value.toKeyValues();
+		Stream *stream = *it;
+		it++;
 
 		if (conf.isSet("width"))
 			(*config)[stream].width = conf["width"];
@@ -136,7 +181,6 @@ static void requestComplete(Request *request, const std::map<Stream *, Buffer *>
 static int capture()
 {
 	CameraConfiguration config;
-	std::vector<Request *> requests;
 	int ret;
 
 	ret = prepareCameraConfig(&config);
@@ -151,8 +195,6 @@ static int capture()
 		return ret;
 	}
 
-	Stream *stream = config.front();
-
 	ret = camera->allocateBuffers();
 	if (ret) {
 		std::cerr << "Failed to allocate buffers"
@@ -162,9 +204,18 @@ static int capture()
 
 	camera->requestCompleted.connect(requestComplete);
 
-	BufferPool &pool = stream->bufferPool();
+	/* Identify the stream with the least number of buffers. */
+	unsigned int nbuffers = UINT_MAX;
+	for (Stream *stream : config)
+		nbuffers = std::min(nbuffers, stream->bufferPool().count());
 
-	for (Buffer &buffer : pool.buffers()) {
+	/*
+	 * TODO: make cam tool smarter to support still capture by for
+	 * example pushing a button. For now run all streams all the time.
+	 */
+
+	std::vector<Request *> requests;
+	for (unsigned int i = 0; i < nbuffers; i++) {
 		Request *request = camera->createRequest();
 		if (!request) {
 			std::cerr << "Can't create request" << std::endl;
@@ -173,7 +224,9 @@ static int capture()
 		}
 
 		std::map<Stream *, Buffer *> map;
-		map[stream] = &buffer;
+		for (Stream *stream : config)
+			map[stream] = &stream->bufferPool().buffers()[i];
+
 		ret = request->setBuffers(map);
 		if (ret < 0) {
 			std::cerr << "Can't set buffers for request" << std::endl;
-- 
2.21.0