libavcodec/mjpegdec.c:877: error: Uninitialized Value
  The value read from linesize[_] was never initialized.

libavcodec/mjpegdec.c:877:21: 
875.                 y = 0;
876.                 for (j = 0; j < n; j++) {
877.                     block_offset = (((linesize[c] * (v * mb_y + y) * 8) +
                         ^
878.                                      (h * mb_x + x) * 8) >> s->avctx->lowres);
879. 
