libavcodec/mjpegdec.c:844: error: Uninitialized Value
  The value read from linesize[_] was never initialized.

libavcodec/mjpegdec.c:844:25: 
842. 
843.                     if(s->interlaced && s->bottom_field)
844.                         block_offset += linesize[c] >> 1;
                             ^
845.                     ptr = data[c] + block_offset;
846.                     if(!s->progressive) {
