AV_AUDIO_SERVICE_TYPE_VOICE_OVER 1939 libavcodec/ac3enc.c           avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_VOICE_OVER)
AV_AUDIO_SERVICE_TYPE_VOICE_OVER  476 libavcodec/options_table.h {"vo", "Voice Over",         0, AV_OPT_TYPE_CONST, {.i64 = AV_AUDIO_SERVICE_TYPE_VOICE_OVER },        INT_MIN, INT_MAX, A|E, "audio_service_type"},
AV_AUDIO_SERVICE_TYPE_VOICE_OVER  163 libavfilter/af_ashowinfo.c     case AV_AUDIO_SERVICE_TYPE_VOICE_OVER:        av_log(ctx, AV_LOG_INFO, "Voice Over");         break;