Add fallback sizes and framerates to v4l2 plugin.

Until a proper fix is found to support devices that use stepwise
or continuous values for framesize and framerate this adds fixed
values that can be selected.
For devices that support discrete values those are still queried
and used.

plugins/linux-v4l2/v4l2-input.c

@@ -92,6 +92,57 @@ static void unpack_tuple(int *a, int *b, int packed)
 	*b = packed & 0xffff;
 }
 
+/* fixed framesizes as fallback */
+static int fixed_framesizes[] =
+{
+	/* 4:3 */
+	160<<16		| 120,
+	320<<16		| 240,
+	480<<16		| 320,
+	640<<16		| 480,
+	800<<16		| 600,
+	1024<<16	| 768,
+	1280<<16	| 960,
+	1440<<16	| 1050,
+	1440<<16	| 1080,
+	1600<<16	| 1200,
+
+	/* 16:9 */
+	640<<16		| 360,
+	960<<16		| 540,
+	1280<<16	| 720,
+	1600<<16	| 900,
+	1920<<16	| 1080,
+	1920<<16	| 1200,
+
+	/* tv */
+	432<<16		| 520,
+	480<<16		| 320,
+	480<<16		| 530,
+	486<<16		| 440,
+	576<<16		| 310,
+	576<<16		| 520,
+	576<<16		| 570,
+	1024<<16	| 576,
+
+	0
+};
+
+/* fixed framerates as fallback */
+static int fixed_framerates[] =
+{
+	1<<16		| 60,
+	1<<16		| 50,
+	1<<16		| 30,
+	1<<16		| 25,
+	1<<16		| 20,
+	1<<16		| 15,
+	1<<16		| 10,
+	1<<16		| 5,
+
+	0
+};
+
 /*
  * start capture
  */
@@ -304,6 +355,7 @@ static void v4l2_device_list(obs_property_t prop, obs_data_t settings)
 		return;
 
 	obs_property_list_clear(prop);
+
 	dstr_init_copy(&device, "/dev/");
 
 	while ((dp = readdir(dirp)) != NULL) {
@@ -386,18 +438,34 @@ static void v4l2_resolution_list(int dev, uint_fast32_t pixelformat,
 
 	obs_property_list_clear(prop);
 
-	while (ioctl(dev, VIDIOC_ENUM_FRAMESIZES, &frmsize) == 0) {
-		dstr_printf(&buffer, "%dx%d", frmsize.discrete.width,
-				frmsize.discrete.height);
-		obs_property_list_add_int(prop, buffer.array,
-				pack_tuple(frmsize.discrete.width,
-				frmsize.discrete.height));
-		frmsize.index++;
-	}
-
-	if (frmsize.type != V4L2_FRMSIZE_TYPE_DISCRETE) {
+	ioctl(dev, VIDIOC_ENUM_FRAMESIZES, &frmsize);
+
+	switch(frmsize.type) {
+	case V4L2_FRMSIZE_TYPE_DISCRETE:
+		while (ioctl(dev, VIDIOC_ENUM_FRAMESIZES, &frmsize) == 0) {
+			dstr_printf(&buffer, "%dx%d", frmsize.discrete.width,
+					frmsize.discrete.height);
+			obs_property_list_add_int(prop, buffer.array,
+					pack_tuple(frmsize.discrete.width,
+					frmsize.discrete.height));
+			frmsize.index++;
+		}
+		break;
+	default:
 		blog(LOG_INFO, "Stepwise and Continuous framesizes "
-			"are currently not supported");
+			"are currently hardcoded");
+
+		for (uint_fast32_t i = 0; ; ++i) {
+			int packed = fixed_framesizes[i];
+			if (!packed)
+				break;
+			int width;
+			int height;
+			unpack_tuple(&width, &height, packed);
+			dstr_printf(&buffer, "%dx%d", width, height);
+			obs_property_list_add_int(prop, buffer.array, packed);
+		}
+		break;
 	}
 
 	dstr_free(&buffer);
@@ -419,19 +487,35 @@ static void v4l2_framerate_list(int dev, uint_fast32_t pixelformat,
 
 	obs_property_list_clear(prop);
 
-	while (ioctl(dev, VIDIOC_ENUM_FRAMEINTERVALS, &frmival) == 0) {
-		float fps = (float) frmival.discrete.denominator /
-			frmival.discrete.numerator;
-		int pack = pack_tuple(frmival.discrete.numerator,
-				frmival.discrete.denominator);
-		dstr_printf(&buffer, "%.2f", fps);
-		obs_property_list_add_int(prop, buffer.array, pack);
-		frmival.index++;
-	}
-
-	if (frmival.type != V4L2_FRMIVAL_TYPE_DISCRETE) {
+	ioctl(dev, VIDIOC_ENUM_FRAMEINTERVALS, &frmival);
+
+	switch(frmival.type) {
+	case V4L2_FRMIVAL_TYPE_DISCRETE:
+		while (ioctl(dev, VIDIOC_ENUM_FRAMEINTERVALS, &frmival) == 0) {
+			float fps = (float) frmival.discrete.denominator /
+				frmival.discrete.numerator;
+			int pack = pack_tuple(frmival.discrete.numerator,
+					frmival.discrete.denominator);
+			dstr_printf(&buffer, "%.2f", fps);
+			obs_property_list_add_int(prop, buffer.array, pack);
+			frmival.index++;
+		}
+		break;
+	default:
 		blog(LOG_INFO, "Stepwise and Continuous framerates "
-			"are currently not supported");
+			"are currently hardcoded");
+		for (uint_fast32_t i = 0; ; ++i) {
+			int packed = fixed_framerates[i];
+			if (!packed)
+				break;
+			int num;
+			int denom;
+			unpack_tuple(&num, &denom, packed);
+			float fps = (float) denom / num;
+			dstr_printf(&buffer, "%.2f", fps);
+			obs_property_list_add_int(prop, buffer.array, packed);
+		}
+		break;
 	}
 
 	dstr_free(&buffer);