[libcamera-devel] [PATCH v2] Add enable_auto_focus option to the GStreamer plugin

[Nicolas Dufresne]

Hi,

Le lundi 05 juin 2023 à 16:44 +0200, Cedric Nugteren via libcamera-devel a
écrit :
> Cameras such as the PiCam 3 support auto-focus, but the GStreamer plugin
> for libcamera does not enable auto-focus. With this patch auto-focus can
> be enabled for cameras that support it. By default it is disabled, which
> means default behaviour remains unchanged. For cameras that do not
> support auto-focus, an error message shows up if it auto-focus is
> enabled.
> 
> This was tested on cameras that do not support auto-focus (e.g. PiCam2)
> and was tested on a camera that does support auto-focus (PiCam3) by
> enabling it, observing auto-focus, and by disabling it or by not setting
> the option, both resulting in auto-focus being disabled.
> 
> This should close https://bugs.libcamera.org/show_bug.cgi?id=188.
> 
> Signed-off-by: Cedric Nugteren <web at cedricnugteren.nl>
> ---
> Changes since v1:
> - Now re-using the GParamSpec variables instead of re-creating.
> - Use bool instead of gboolean for enable_auto_focus.
> - Remove changes from the reconfigure_element functions.
> ---
>  src/gstreamer/gstlibcameraprovider.cpp | 12 +++++++++++
>  src/gstreamer/gstlibcamerasrc.cpp      | 29 +++++++++++++++++++++++++-
>  2 files changed, 40 insertions(+), 1 deletion(-)
> 
> diff --git a/src/gstreamer/gstlibcameraprovider.cpp b/src/gstreamer/gstlibcameraprovider.cpp
> index 6eb0a0eb..579cb8c0 100644
> --- a/src/gstreamer/gstlibcameraprovider.cpp
> +++ b/src/gstreamer/gstlibcameraprovider.cpp
> @@ -31,6 +31,7 @@ GST_DEBUG_CATEGORY_STATIC(provider_debug);
>  
>  enum {
>  	PROP_DEVICE_NAME = 1,
> +	PROP_ENABLE_AUTO_FOCUS = 2,
>  };
>  
>  #define GST_TYPE_LIBCAMERA_DEVICE gst_libcamera_device_get_type()
> @@ -40,6 +41,7 @@ G_DECLARE_FINAL_TYPE(GstLibcameraDevice, gst_libcamera_device,
>  struct _GstLibcameraDevice {
>  	GstDevice parent;
>  	gchar *name;
> +	bool enable_auto_focus = false;
>  };
>  
>  G_DEFINE_TYPE(GstLibcameraDevice, gst_libcamera_device, GST_TYPE_DEVICE)
> @@ -56,6 +58,7 @@ gst_libcamera_device_create_element(GstDevice *device, const gchar *name)
>  	g_assert(source);
>  
>  	g_object_set(source, "camera-name", GST_LIBCAMERA_DEVICE(device)->name, nullptr);
> +	g_object_set(source, "enable-auto-focus", GST_LIBCAMERA_DEVICE(device)->enable_auto_focus, nullptr);
>  
>  	return source;
>  }
> @@ -82,6 +85,9 @@ gst_libcamera_device_set_property(GObject *object, guint prop_id,
>  	case PROP_DEVICE_NAME:
>  		device->name = g_value_dup_string(value);
>  		break;
> +	case PROP_ENABLE_AUTO_FOCUS:
> +		device->enable_auto_focus = g_value_get_boolean(value);
> +		break;
>  	default:
>  		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
>  		break;
> @@ -121,6 +127,12 @@ gst_libcamera_device_class_init(GstLibcameraDeviceClass *klass)
>  						(GParamFlags)(G_PARAM_STATIC_STRINGS | G_PARAM_WRITABLE |
>  							      G_PARAM_CONSTRUCT_ONLY));
>  	g_object_class_install_property(object_class, PROP_DEVICE_NAME, pspec);
> +	pspec = g_param_spec_boolean("enable-auto-focus",
> +	                             "Enable auto-focus",
> +	                             "Enable auto-focus if set to true, "
> +	                             "disable it if set to false",
> +	                              FALSE, G_PARAM_WRITABLE);
> +	g_object_class_install_property(object_class, PROP_ENABLE_AUTO_FOCUS, pspec);
>  }
>  
>  static GstDevice *
> diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> index a10cbd4f..b2d8456b 100644
> --- a/src/gstreamer/gstlibcamerasrc.cpp
> +++ b/src/gstreamer/gstlibcamerasrc.cpp
> @@ -146,6 +146,7 @@ struct _GstLibcameraSrc {
>  	GstTask *task;
>  
>  	gchar *camera_name;
> +	bool enable_auto_focus = false;
>  
>  	GstLibcameraSrcState *state;
>  	GstLibcameraAllocator *allocator;
> @@ -154,7 +155,8 @@ struct _GstLibcameraSrc {
>  
>  enum {
>  	PROP_0,
> -	PROP_CAMERA_NAME
> +	PROP_CAMERA_NAME,
> +	PROP_ENABLE_AUTO_FOCUS,
>  };
>  
>  G_DEFINE_TYPE_WITH_CODE(GstLibcameraSrc, gst_libcamera_src, GST_TYPE_ELEMENT,
> @@ -577,6 +579,18 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
>  		gst_flow_combiner_add_pad(self->flow_combiner, srcpad);
>  	}
>  
> +	if (self->enable_auto_focus) {
> +		const ControlInfoMap &infoMap = state->cam_->controls();
> +		if (infoMap.find(&controls::AfMode) != infoMap.end()) {
> +			state->initControls_.set(controls::AfMode, controls::AfModeContinuous);

I don't really like the idea of mapping modes to a boolean here. I think this
should be an GEnum type of property. Some mode requires some actions to actually
work, best to just skip these for now.

> +		} else {
> +			GST_ELEMENT_ERROR(self, RESOURCE, SETTINGS,
> +				("Failed to enable auto focus"),
> +				("AfMode not found in camera controls, "
> +				"please retry with 'enable-auto-focus=false'"));
> +		}
> +	}
> +
>  	ret = state->cam_->start(&state->initControls_);
>  	if (ret) {
>  		GST_ELEMENT_ERROR(self, RESOURCE, SETTINGS,
> @@ -659,6 +673,9 @@ gst_libcamera_src_set_property(GObject *object, guint prop_id,
>  		g_free(self->camera_name);
>  		self->camera_name = g_value_dup_string(value);
>  		break;
> +	case PROP_ENABLE_AUTO_FOCUS:
> +		self->enable_auto_focus = g_value_get_boolean(value);
> +		break;
>  	default:
>  		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
>  		break;
> @@ -676,6 +693,9 @@ 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_ENABLE_AUTO_FOCUS:
> +		g_value_set_boolean(value, self->enable_auto_focus);
> +		break;
>  	default:
>  		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
>  		break;
> @@ -844,4 +864,11 @@ gst_libcamera_src_class_init(GstLibcameraSrcClass *klass)
>  							     | G_PARAM_READWRITE
>  							     | G_PARAM_STATIC_STRINGS));
>  	g_object_class_install_property(object_class, PROP_CAMERA_NAME, spec);
> +	spec = g_param_spec_boolean("enable-auto-focus",
> +	                            "Enable auto-focus",
> +	                            "Enable auto-focus if set to true, "
> +	                            "disable it if set to false",
> +	                             FALSE, G_PARAM_WRITABLE);
> +	g_object_class_install_property(object_class, PROP_ENABLE_AUTO_FOCUS, spec);
> +
>  }