[libcamera-devel] [PATCH] gstreamer: Add 'list-cameras' property

[Nicolas Dufresne]

Hi Ujain,

Le lundi 03 juillet 2023 à 21:57 +0200, Umang Jain a écrit :
> Add a new property called 'list-cameras' on libcamerasrc to enumerate
> and expose the cameras present on the system. The enumeration will help
> appplications using libcamerasrc to know and set the 'camera-name'
> property in order to use that camera with libcamerasrc.
> 
> Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>

I'm sorry, but I have to reject this. This is the job of the device provider. If
some information is missing in the provider, just add it there.

NAK

> ---
>  src/gstreamer/gstlibcamerasrc.cpp | 46 +++++++++++++++++++++++++++++++
>  test/gstreamer/gstreamer_test.cpp | 30 ++++++++++++++++++++
>  test/gstreamer/gstreamer_test.h   |  2 ++
>  3 files changed, 78 insertions(+)
> 
> diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> index 1f10136b..f337728a 100644
> --- a/src/gstreamer/gstlibcamerasrc.cpp
> +++ b/src/gstreamer/gstlibcamerasrc.cpp
> @@ -152,6 +152,7 @@ struct _GstLibcameraSrc {
>  enum {
>  	PROP_0,
>  	PROP_CAMERA_NAME,
> +	PROP_LIST_CAMERAS,
>  	PROP_AUTO_FOCUS_MODE,
>  };
>  
> @@ -666,6 +667,39 @@ gst_libcamera_src_close(GstLibcameraSrc *self)
>  	state->cm_.reset();
>  }
>  
> +static gboolean
> +gst_libcamera_src_set_cameras_list(GstLibcameraSrc *self, GValue *value)
> +{
> +	std::shared_ptr<CameraManager> cm;
> +	GValue val = G_VALUE_INIT;
> +	gint ret;
> +
> +	g_value_init(&val, G_TYPE_STRING);
> +	g_value_reset(value);
> +
> +	cm = gst_libcamera_get_camera_manager(ret);
> +	if (ret) {
> +		GST_ELEMENT_ERROR(self, LIBRARY, INIT,
> +				  ("Failed listing cameras."),
> +				  ("libcamera::CameraMananger::start() failed: %s", g_strerror(-ret)));
> +		return false;
> +	}
> +
> +	if (cm->cameras().empty()) {
> +		GST_ELEMENT_ERROR(self, RESOURCE, NOT_FOUND,
> +				  ("Could not find any supported camera on this system."),
> +				  ("libcamera::CameraMananger::cameras() is empty"));
> +		return false;
> +	}
> +
> +	for (const std::shared_ptr<Camera> &cam : cm->cameras()) {
> +		g_value_set_string(&val, cam->id().c_str());
> +		gst_value_array_append_value(value, &val);
> +	}
> +
> +	return true;
> +}
> +
>  static void
>  gst_libcamera_src_set_property(GObject *object, guint prop_id,
>  			       const GValue *value, GParamSpec *pspec)
> @@ -699,6 +733,9 @@ gst_libcamera_src_get_property(GObject *object, guint prop_id, GValue *value,
>  	case PROP_CAMERA_NAME:
>  		g_value_set_string(value, self->camera_name);
>  		break;
> +	case PROP_LIST_CAMERAS:
> +		gst_libcamera_src_set_cameras_list(self, value);
> +		break;
>  	case PROP_AUTO_FOCUS_MODE: {
>  		auto auto_focus_mode = self->controls->get(controls::AfMode).value_or(controls::AfModeManual);
>  		g_value_set_enum(value, auto_focus_mode);
> @@ -879,6 +916,15 @@ gst_libcamera_src_class_init(GstLibcameraSrcClass *klass)
>  							     | G_PARAM_STATIC_STRINGS));
>  	g_object_class_install_property(object_class, PROP_CAMERA_NAME, spec);
>  
> +	spec = gst_param_spec_array("list-cameras", "Cameras list",
> +				    "Retrieve list of all cameras",
> +				    g_param_spec_string("camera-name", "Camera name",
> +							"Name of the camera", nullptr,
> +							(GParamFlags)(G_PARAM_READABLE
> +								      | G_PARAM_STATIC_STRINGS)),
> +				    (GParamFlags)(G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
> +	g_object_class_install_property(object_class, PROP_LIST_CAMERAS, spec);
> +
>  	spec = g_param_spec_enum("auto-focus-mode",
>  				 "Set auto-focus mode",
>  				 "Available options: AfModeManual, "
> diff --git a/test/gstreamer/gstreamer_test.cpp b/test/gstreamer/gstreamer_test.cpp
> index 6ad0c15c..7f3ccd2b 100644
> --- a/test/gstreamer/gstreamer_test.cpp
> +++ b/test/gstreamer/gstreamer_test.cpp
> @@ -97,6 +97,9 @@ bool GstreamerTest::checkMinCameraStreamsAndSetCameraName(unsigned int numStream
>  		break;
>  	}
>  
> +	for (auto &camera : cm.cameras())
> +		cameraNames_.push_back(strdup(camera->id().c_str()));
> +
>  	cm.stop();
>  
>  	return cameraFound;
> @@ -112,6 +115,9 @@ GstreamerTest::~GstreamerTest()
>  
>  int GstreamerTest::createPipeline()
>  {
> +	GValue cameras_list_array = G_VALUE_INIT;
> +	guint index, i;
> +
>  	libcameraSrc_ = gst_element_factory_make("libcamerasrc", "libcamera");
>  	pipeline_ = gst_pipeline_new("test-pipeline");
>  
> @@ -125,6 +131,30 @@ int GstreamerTest::createPipeline()
>  	g_object_set(libcameraSrc_, "camera-name", cameraName_.c_str(), NULL);
>  	g_object_ref_sink(libcameraSrc_);
>  
> +	g_value_init(&cameras_list_array, GST_TYPE_ARRAY);
> +	g_object_get_property(G_OBJECT(libcameraSrc_), "list-cameras", &cameras_list_array);
> +	if (gst_value_array_get_size(&cameras_list_array) != cameraNames_.size()) {
> +		g_printerr("libcamerasrc 'list-cameras' properties count does not match.\n");
> +		return TestFail;
> +	}
> +
> +	for (index = 0; index < cameraNames_.size(); index++) {
> +		bool matched = false;
> +
> +		for (i = 0; i < gst_value_array_get_size(&cameras_list_array); i++) {
> +			const char *cam = g_value_get_string(gst_value_array_get_value(&cameras_list_array, i));
> +			if (strcmp(cam, cameraNames_[index]) == 0) {
> +				matched = true;
> +				break;
> +			}
> +		}
> +
> +		if (!matched) {
> +			g_printerr("Camera %s not found in 'list-cameras' property.\n", cameraNames_[index]);
> +			return TestFail;
> +		}
> +	}
> +
>  	return TestPass;
>  }
>  
> diff --git a/test/gstreamer/gstreamer_test.h b/test/gstreamer/gstreamer_test.h
> index aa2261e2..5d61bc2a 100644
> --- a/test/gstreamer/gstreamer_test.h
> +++ b/test/gstreamer/gstreamer_test.h
> @@ -9,6 +9,7 @@
>  
>  #include <iostream>
>  #include <unistd.h>
> +#include <vector>
>  
>  #include <gst/gst.h>
>  
> @@ -29,6 +30,7 @@ protected:
>  	GstElement *libcameraSrc_;
>  	int status_;
>  
> +	std::vector<const char *> cameraNames_;
>  private:
>  	bool checkMinCameraStreamsAndSetCameraName(unsigned int numStreams);
>  };