[PATCH] v4l2: Fix 4K colorimetry
+
+Since 1.6, the transfer function for BT2020 has been changed from BT709
+to BT2020_12. It's the same function, but with more precision. As a side
+effect, the V4L2 colorpsace didn't match GStreamer colorspace. When
+GStreamer ended up making a guess, it would not match anything supported
+by V4L2 anymore. This this by using BT2020_12 for BT2020 colorspace and
+BT2020 transfer function in replacement of BT709 whenever a 4K
+resolution is detected.

+@@ -2062,7 +2062,10 @@ gst_v4l2_object_get_colorspace (struct v4l2_format *fmt,
+ 
+   switch (transfer) {
+     case V4L2_XFER_FUNC_709:
+-      cinfo->transfer = GST_VIDEO_TRANSFER_BT709;
++      if (fmt->fmt.pix.height > 2160)
++        cinfo->transfer = GST_VIDEO_TRANSFER_BT2020_12;
++      else
++        cinfo->transfer = GST_VIDEO_TRANSFER_BT709;
+       break;

This height comparison should be >= 2160.