ffmpeg.c:1690: error: Uninitialized Value
  The value read from quality was never initialized.

ffmpeg.c:1690:42: 
1688. #endif
1689.                             do_video_out(os, ost, ist, &picture, &frame_size,
1690.                                          same_quality ? quality : ost->st->codec->global_quality);
                                               ^
1691.                             if (vstats_filename && frame_size)
1692.                                 do_video_stats(os, ost, frame_size);
