put_ebml_string(pb, MATROSKA_ID_TRACKNAME, tag->value);
tag = av_dict_get(st->metadata, "language", NULL, 0);
if (mkv->mode != MODE_WEBM || codec->codec_id != AV_CODEC_ID_WEBVTT) {
- put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, tag ? tag->value:"und");
+ put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, tag && tag->value ? tag->value:"und");
} else if (tag && tag->value) {
put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, tag->value);
}