libavcodec/mpegvideo.c:644: error: Uninitialized Value
  The value read from y_size was never initialized.

libavcodec/mpegvideo.c:644:13: 
642.             FF_ALLOCZ_OR_GOTO(s->avctx, s->dc_val_base, yc_size * sizeof(int16_t), fail);
643.             s->dc_val[0] = s->dc_val_base + s->b8_stride + 1;
644.             s->dc_val[1] = s->dc_val_base + y_size + s->mb_stride + 1;
                 ^
645.             s->dc_val[2] = s->dc_val[1] + c_size;
646.             for(i=0;i<yc_size;i++)
