使用vlc-qt录制时如何同时播放和录制

Question

我正在使用VLC-QT V1.1.0和libVlc V2.2.4，并希望同时记录和播放rtsp / rtmp流。但是我发现同时记录和播放时，仅显示视频，没有音频输出。我也无法成功设置音量。

libvlc显示如下错误：“无活动音频输出”。

Vlc::Mux fileType = Vlc::MP4;
QString out_file = "testrecord";
QString out_file_path = "D://";
_media1 = new VlcMedia("rtmp://live.hkstv.hk.lxdns.com/live/hks1",_instance1);
_media1->record(out_file, out_file_path, fileType, true);
_player1->open(_media1);
while (true)
{
    Vlc::State state = _media1->state();
    if (state != Vlc::State::Playing)
    {
        _sleep(1000);
    }
    else
    {
        bool mute = _player1->audio()->getMute();
        int volume = _player1->audio()->volume();
        _player1->audio()->setVolume(100);
        volume = _player1->audio()->volume();
        mute = _player1->audio()->getMute();
        break;
    }
}