if (zret != Z_OK) {
            av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", zret);
            return -1;
        }

        c->cur  = av_realloc_f(c->cur, avctx->width * avctx->height,  (c->bpp / 8));
        c->prev = av_realloc_f(c->prev, avctx->width * avctx->height,  (c->bpp / 8));
        c->cur = NULL;
        c->prev = NULL;
        c->bx = (c->width + c->bw - 1) / c->bw;
        c->by = (c->height+ c->bh - 1) / c->bh;
        if (!c->cur || !c->prev)