合并两个有和没有音频的剪辑会导致音频在生成的视频中从头开始

Posted 2023-02-25

【中文标题】合并两个有和没有音频的剪辑会导致音频在生成的视频中从头开始

【英文标题】：Merging two clips with & without audio causes the audio to start from beginning in the generated video

【发布时间】：2020-01-23 06:13:37

【问题描述】：

我正在尝试使用 MP4Parser 将两个视频（mp4 文件）合并为一个视频，一个有音频，一个没有音频。生成的最终视频始终具有从头开始的音频。 例如第一个视频的长度为 20 秒，没有音频。第二个视频长度为 10 秒，有音频。 生成的最终视频长度为 30 秒，但音频将在视频开头播放 10 秒（其余 20 秒不会有任何音频），而它应该开始 20 秒没有音频，结束 10 秒有音频。

Movie[] clips = new Movie[2];

//location of the movie clip storage
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
        Environment.DIRECTORY_PICTURES), "TestMerge");

//Build the two clips into movies
Movie firstClip = MovieCreator.build(first);
Movie secondClip = MovieCreator.build(second);

//Add both movie clips
clips[0] = firstClip;
clips[1] = secondClip;

//List for audio and video tracks
List<Track> videoTracks = new LinkedList<Track>();
List<Track> audioTracks = new LinkedList<Track>();

//Iterate all the movie clips and find the audio and videos
for (Movie movie: clips) 
    for (Track track : movie.getTracks()) 
        if (track.getHandler().equals("soun")) 
            audioTracks.add(track);                
        if (track.getHandler().equals("vide"))
            videoTracks.add(track);
    


//Result movie from putting the audio and video together from the two clips
Movie result = new Movie();

//Append all audio and video
if (videoTracks.size() > 0)
    result.addTrack(new AppendTrack(videoTracks.toArray(new Track[videoTracks.size()])));

if (audioTracks.size() > 0) 
    result.addTrack(new AppendTrack(audioTracks.toArray(new Track[audioTracks.size()])));

我尝试通过更改以下几行来添加静音轨道

//List for audio and video tracks
List<Track> videoTracks = new LinkedList<Track>();
List<Track> audioTracks = new LinkedList<Track>();
Track audiosourceTrack = null;

    for (final Movie movie : inMovies) 
        for (final Track t : movie.getTracks()) 
            if (isAudioTrack(t)) 
                audioSourceTrack = t;
                break;
            
        
        if (audioSourceTrack != null) break;
    

    //Iterate all the movie clips and find the audio and videos
for (Movie movie: clips) 
        if (movie.getTracks().size() == 1) 
            videoTracks.add(movie.getTracks().get(0));
            audioTracks.add(new SilenceTrackImpl(audioSourceTrack, movie.getTracks().get(0).getDuration() / 2));
         else 
            for (final Track t : movie.getTracks()) 
                if (isAudioTrack(t)) 
                    audioTracks.add(t);
                
                if (isVideoTrack(t)) 
                    videoTracks.add(t);
                
            
        
    

【参考方案1】：

我可以通过将静音剪辑附加静音轨道来做到这一点。问题是 react-native-video 没有像 Q 播放器那样正确播放静音轨道。我必须对视频进行转码才能看到附加的静音是否正常工作。