static int get_moov_size(AVFormatContext *s) { int ret; AVIOContext *moov_buf; MOVMuxContext *mov = s->priv_data; if ((ret = ffio_open_null_buf(&moov_buf)) < 0) return ret; mov_write_moov_tag(moov_buf, mov, s); return ffio_close_null_buf(moov_buf); }