Properly query video device pixel format

The `ioctl` to query `VIDIOC_G_FMT` was previously unchecked and always failed due to a missing initialization of the structure passed.
floe · Jan 22, 2022 · 56d94fd · 56d94fd
1 parent e3d1c22
commit 56d94fd
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/videoio/loopback.cc b/videoio/loopback.cc
@@ -51,9 +51,14 @@ int loopback_init(const std::string& device, int w, int h, int debug) {
 	}
 
 	memset(&vid_format, 0, sizeof(vid_format));
-	//usleep(100000);
+	vid_format.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
 
 	ret_code = ioctl(fdwr, VIDIOC_G_FMT, &vid_format);
+	if(ret_code < 0) {
+		fprintf(stderr, "%s:%d(%s): Failed to get device video format: %s\n", __FILE__, __LINE__, __func__, strerror(errno));
+		close(fdwr);
+		return -1;
+	}
 
 	vid_format.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
 	vid_format.fmt.pix.width = w;