libavcodec/mjpegdec.c:840: error: Uninitialized Value
  The value read from linesize[_] was never initialized.

libavcodec/mjpegdec.c:840:21: 
838.                 y = 0;
839.                 for(j=0;j<n;j++) {
840.                     block_offset = (((linesize[c] * (v * mb_y + y) * 8) +
                         ^
841.                                      (h * mb_x + x) * 8) >> s->avctx->lowres);
842. 
