libavcodec/mpegvideo.c:631: error: Uninitialized Value
  The value read from y_size was never initialized.

libavcodec/mpegvideo.c:631:13: 
629.         if (s->out_format == FMT_H263) {
630.             /* cbp values */
631.             FF_ALLOCZ_OR_GOTO(s->avctx, s->coded_block_base, y_size, fail);
                 ^
632.             s->coded_block= s->coded_block_base + s->b8_stride + 1;
633. 
