Android Appending 2 Mp4 Byte Arrays Together to Then Output 1 Mp4 File (where final video is first video plus second video)

Question

Hi I've been having a lot of trouble with this, I have 2 Files, both Mp4 format, read them into FileInputStreams, then into ByteArrayOutputStreams. I then try to append the two byte arrays by using another ByteArrayOutputStream [finalOutputStream] and write()'ing the two. Finally I use FileOutputStream to write(finalOutputStream.toByteArray()), flush, close. When i look for the video on my phone, there is a "Final" video that should have the 2 combined videos, with a size that looks like the two part's sizes added together.. but when i watch the video, it is only the second part -_- ... it is like the second part overwrites the first, but somehow the size increases?... heres some code..

    File fileOne = new File(fileLongName);
    File fileTwo = new File(mediaStorageDir.getPath() + File.separator +"VID_TUTPART_"+ (foo-1) + ".mp4");
    FileInputStream fisOne = new FileInputStream(fileOne);
    FileInputStream fisTwo = new FileInputStream(fileTwo);

    int bufferSize = 1024;
    //FileOne
    byte[] buffer = new byte[bufferSize];
    ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream();

    //FileTwo
    byte[] bufferTwo = new byte[bufferSize];
    ByteArrayOutputStream byteBufferTwo = new ByteArrayOutputStream();

    int len = 0;
    //FileOne to bytebuffer
    while ((len = fisOne.read(buffer)) != -1) {
      byteBuffer.write(buffer, 0, len);
    }
    //FileTwo to bytebuffer
    while ((len = fisTwo.read(bufferTwo)) != -1) {
      byteBufferTwo.write(buffer, 0, len);
    }
    byte[] byteArrayOne = byteBuffer.toByteArray();
    byte[] byteArrayTwo = byteBuffer.toByteArray();

    ByteArrayOutputStream finalOutputStream = new ByteArrayOutputStream( );
    finalOutputStream.write( byteArrayOne );
    finalOutputStream.write( byteArrayTwo );

    int counterFileNumber = 0;
    while(new File(mediaStorageDir.getPath() + File.separator +"VID_TO_TUTFIN_"+ counterFileNumber + ".mp4").exists()){
        counterFileNumber++;
    }

    String outputFileNameString = mediaStorageDir.getPath() + File.separator +"VID_TO_TUTFIN_"+ counterFileNumber + ".mp4";
    File outputFile = new File(outputFileNameString);
    FileOutputStream fos = new FileOutputStream(outputFile);
    fos.write(finalOutputStream.toByteArray());
    fos.flush();
    fos.close();

Answer 1

@Benoit With your help came up with this.. hope it helps someone else

    File fileOne = new File(mediaStorageDir.getPath() + File.separator +"theNameOfMyFirstVideo.mp4");
    File fileTwo = new File(mediaStorageDir.getPath() + File.separator +"theNameOfMySecondVideo.mp4");
    FileInputStream fisOne = new FileInputStream(fileOne);
    FileInputStream fisTwo = new FileInputStream(fileTwo);      

    Movie video = MovieCreator.build(Channels.newChannel(fisOne));
    Movie videoTwo = MovieCreator.build(Channels.newChannel(fisTwo));

    List<Track> videoTracks = video.getTracks();
    Track testOneVideoTrack = videoTracks.get(0);
    video.setTracks(new LinkedList<Track>());

    List<Track> videoTwoTracks = videoTwo.getTracks();
    Track testTwoVideoTrack = videoTwoTracks.get(0);

    video.addTrack(new AppendTrack(testTwoVideoTrack,testOneVideoTrack));

    int counterFileNumber = 0;
    while(new File(mediaStorageDir.getPath() + File.separator +"VID_TO_TUTFIN_"+ counterFileNumber + ".mp4").exists()){
        counterFileNumber++;
    }

    IsoFile out = new DefaultMp4Builder().build(video);
    String outputFileNameString = mediaStorageDir.getPath() + File.separator +"VID_TO_TUTFIN_"+ counterFileNumber + ".mp4";
    FileOutputStream fos = new FileOutputStream(new File(String.format(outputFileNameString)));
    out.getBox(fos.getChannel());
    fos.close();

When i was debugging, i looked at the List videoTracks and saw with the first element [0] there was something about "vide" and the element [1] had "soun" so started working with that..

Answer 2

If you simply make a append the video together it won't work, you also need to rewrite the header.

I did this recently by using mp4parser

Then you can follow the sample

MovieCreator mc = new MovieCreator();
Movie video = mc.build(Channels.newChannel(AppendExample.class.getResourceAsStream("/count-video.mp4")));
Movie audio = mc.build(Channels.newChannel(AppendExample.class.getResourceAsStream("/count-english-audio.mp4")));


List<Track> videoTracks = video.getTracks();
video.setTracks(new LinkedList<Track>());

List<Track> audioTracks = audio.getTracks();


for (Track videoTrack : videoTracks) {
   video.addTrack(new AppendTrack(videoTrack, videoTrack));
}
for (Track audioTrack : audioTracks) {
   video.addTrack(new AppendTrack(audioTrack, audioTrack));
}

IsoFile out = new DefaultMp4Builder().build(video);
FileOutputStream fos = new FileOutputStream(new File(String.format("output.mp4")));
out.getBox(fos.getChannel());
fos.close();