gst: gamma control added for aravissrc (help needed)

[WhaSukGO]

Overview

• gamma has been added to aravissrc
• Tested on iRAYPLE's A5051CU545E

 - USB3.0 interface, 5Gbps theoretical transfer bandwidth, power supply via USB interface
 - Compatible with USB3.0 Vision protocol and GenICam standard
 - Support Software Trigger/Hardware Trigger/Free Run Mode
 - Resolution: 800 × 600
 - Frame Rate: 545 fps

Example

$ gst-inspect-1.0 aravissrc
  ...

  gain                : Gain (dB)
                        flags: readable, writable
                        Double. Range:              -1 -             500 Default:              -1 
  gain-auto           : Auto Gain Mode
                        flags: readable, writable
                        Enum "GstArvAuto" Default: 0, "off"
                           (0): off              - Off
                           (1): once             - Once
                           (2): on               - Continuous
  gamma               : Gamma
                        flags: readable, writable
                        Double. Range:               0 -             3.9 Default:               1 

$ gst-launch-1.0 aravissrc exposure=1700 do-timestamp=true gamma=1.0 \
    ! video/x-bayer,format=rggb,width=800,height=600 \
    ! bayer2rgb \
    ! videoconvert \
    ! autovideosink

Help Needed

I was able to adjust gamma using arv_gc_float_set_value() in avexample.c.
However, when I try to retrieve the updated value using arv_device_get_feature_value(), it throws an segmentation fault.

In gstaravis.c, arv_camera_is_feature_available() returns false.

avexample.c

/* Instantiation of the first available camera */
camera = arv_camera_new (NULL, &error);
device = arv_camera_get_device(camera);

gboolean is_gamma_available = arv_camera_is_feature_available (camera, "Gamma", NULL);

if (is_gamma_available) {
	printf ("Gamma feature is available\n");

	double gamma_max, gamma_min;
	gdouble gamma ;

	arv_camera_get_float_bounds(camera, "Gamma", &gamma_min, &gamma_max, &error);
	printf ("Gamma bounds are %f and %f\n", gamma_min, gamma_max);

	ArvGcNode *gamma_node = NULL;
	gamma_node = arv_device_get_feature(device, "Gamma");
	printf("%p\n", gamma_node);

	arv_device_get_feature_value(device, "Gamma", &gamma, &error);
	printf("Gamma: %f\n", gamma);

	// Successful
	arv_gc_float_set_value(gamma_node, 0.5, &error);

	if (error != NULL) {
		printf ("Can't set gamma value: %s\n", error->message);
		g_clear_error (&error);
	} else {
		printf ("Gamma value set to 0.5\n");
	}

	// No response
	// arv_device_set_float_feature_value(device, "Gamma", 0.5, &error);

	// if (error != NULL) {
	// 	printf ("Can't set gamma value: %s\n", error->message);
	// 	g_clear_error (&error);
	// } else {
	// 	printf ("Gamma value set to 0.5\n");
	// }

	// Segmentation fault
	arv_device_get_feature_value(device, "Gamma", &gamma, &error);

	printf("Gamma: %f\n", gamma);

} else {
	printf ("Gamma feature is not available\n");
}

gstaravis.c

		...

		case PROP_GAMMA:
			GST_OBJECT_LOCK (gst_aravis);
			gst_aravis->gamma = g_value_get_double (value);
			// arv_camera_is_feature_available returns FALSE
			if (gst_aravis->camera != NULL &&
				arv_camera_is_feature_available (gst_aravis->camera, "Gamma", NULL)) {
					// Not working
					// arv_device_set_float_feature_value(gst_aravis->camera, "Gamma", gst_aravis->gamma, NULL);			

					double gamma_max, gamma_min;
					arv_camera_get_float_bounds(gst_aravis->camera, "Gamma", &gamma_min, &gamma_max, NULL);

					if (gamma_min <= gst_aravis->gamma && gst_aravis->gamma <= gamma_max) {
						ArvDevice *device = arv_camera_get_device(gst_aravis->camera);
						ArvGcNode *gamma_node = arv_device_get_feature(device, "Gamma");
						arv_gc_float_set_value(ARV_GC_FLOAT(gamma_node), gst_aravis->gamma, NULL);
					}
				}
			GST_OBJECT_UNLOCK (gst_aravis);
			break;

Appreciate any help!

[EmmanuelP]

Hi,

I have created a new pull request from a tweaked version of your patch. It seems to work fine for me. Please test #957 and report any issue there.