MPEG-1 always uses CBR, so make the BITRATE_MODE control inactive.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
                        qctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
                return err;
 
+       case V4L2_CID_MPEG_VIDEO_BITRATE_MODE:
+               err = v4l2_ctrl_query_fill_std(qctrl);
+               if (err == 0 && params->video_encoding == V4L2_MPEG_VIDEO_ENCODING_MPEG_1)
+                       qctrl->flags |= V4L2_CTRL_FLAG_INACTIVE;
+               return err;
+
        case V4L2_CID_MPEG_VIDEO_BITRATE_PEAK:
                err = v4l2_ctrl_query_fill_std(qctrl);
                if (err == 0 && params->video_bitrate_mode == V4L2_MPEG_VIDEO_BITRATE_MODE_CBR)