if ((n = matroska_ebmlnum_uint(matroska, data, size, &num)) < 0) {
av_log(matroska->ctx, AV_LOG_ERROR, "EBML block data error\n");
if ((n = matroska_ebmlnum_uint(matroska, data, size, &num)) < 0) {
av_log(matroska->ctx, AV_LOG_ERROR, "EBML block data error\n");