avconv.c:1710: error: Uninitialized Value
  The value read from quality was never initialized.

avconv.c:1710:38: 
1708. #endif
1709.                         do_video_out(os, ost, ist, &picture, &frame_size,
1710.                                      same_quant ? quality : ost->st->codec->global_quality);
                                           ^
1711.                         if (vstats_filename && frame_size)
1712.                             do_video_stats(os, ost, frame_size);
