libavcodec/mjpegdec.c:797: error: Uninitialized Value
  The value read from linesize[_] was never initialized.

libavcodec/mjpegdec.c:797:21: 
795.                 y = 0;
796.                 for(j=0;j<n;j++) {
797.                     ptr = data[c] +
                         ^
798.                         (((linesize[c] * (v * mb_y + y) * 8) +
799.                         (h * mb_x + x) * 8) >> s->avctx->lowres);
