add filtering to the sample

Author: josuah

samples/subsys/usb/uvc/src/main.c

@@ -32,7 +32,28 @@ static size_t app_get_min_buf_size(const struct video_format *const fmt)
 	}
 }
 
-static void app_add_format(uint32_t pixfmt, uint16_t width, uint16_t height)
+static bool app_is_standard_format(uint32_t pixfmt)
+{
+	return pixfmt == VIDEO_PIX_FMT_GREY || pixfmt == VIDEO_PIX_FMT_JPEG ||
+	       pixfmt == VIDEO_PIX_FMT_YUYV;
+}
+
+/* Check whether the video device supports one of the wisespread image sensor formats */
+static bool app_has_standard_formats(void)
+{
+	for (int i = 0;; i++) {
+		uint32_t pixfmt = video_caps.format_caps[i].pixelformat;
+
+		if (pixfmt == 0) {
+			return false;
+		}
+		if (app_is_standard_format(pixfmt)) {
+			return true;
+		}
+	}
+}
+
+static void app_add_format(uint32_t pixfmt, uint16_t width, uint16_t height, bool has_std_fmts)
 {
 	struct video_format fmt = {
 		.pixelformat = pixfmt,
@@ -42,6 +63,11 @@ static void app_add_format(uint32_t pixfmt, uint16_t width, uint16_t height)
 	};
 	int ret;
 
+	/* If the system has any standard pixel format, only propose them to the host */
+	if (has_std_fmts && !app_is_standard_format(pixfmt)) {
+		return;
+	}
+
 	/* Set the format to get the pitch */
 	ret = video_set_format(video_dev, &fmt);
 	if (ret != 0) {
@@ -60,13 +86,16 @@ static void app_add_format(uint32_t pixfmt, uint16_t width, uint16_t height)
 /* Submit to UVC only the formats expected to be working (enough memory for the size, etc.) */
 static void app_add_filtered_formats(void)
 {
+	const bool has_std_fmts = app_has_standard_formats();
+
 	for (int i = 0; video_caps.format_caps[i].pixelformat != 0; i++) {
 		const struct video_format_cap *vcap = &video_caps.format_caps[i];
 
-		app_add_format(vcap->pixelformat, vcap->width_min, vcap->height_min);
+		app_add_format(vcap->pixelformat, vcap->width_min, vcap->height_min, has_std_fmts);
 
 		if (vcap->width_min != vcap->width_max || vcap->height_min != vcap->height_max) {
-			app_add_format(vcap->pixelformat, vcap->width_max, vcap->height_max);
+			app_add_format(vcap->pixelformat, vcap->width_max, vcap->height_max,
+				       has_std_fmts);
 		}
 	}
 }