block_size = MB_SIZE >> s->block_max_depth;     slice_buffer_init(&s->sb, s->plane[0].height, s->plane[0].height, s->plane[0].width, s->spatial_dwt_buffer);
static int decode_init(AVCodecContext *avctx){//    SnowContext *s = avctx->priv_data;    common_init(avctx);        return 0;}