如何在flutter中合并音频和视频

Question

我用过这个包flutter_ffmpeg：^0.2.10，我的flutter版本是2.0.3，

if (widget.addMusicId != null) {
  print("Merge Audio");
  //-i video.mp4 -i audio.mp4 -c copy output.mp4
  _flutterFFmpeg
      .execute(
          "-i $videoPath -i ${widget.addMusicId} -c copy ${DateTime.now().millisecondsSinceEpoch.toString()}")
      // "-i $videoPath -i ${widget.addMusicId} -c:v libx264 -c:a aac -ac 2 -ar 22050 -map 0:v:0 -map 1:a:0 -shortest $outputVideo")
      .then((rc) => print("FFmpeg process exited with rc $rc"));

  setState(() {
    videoPath = outputVideo;
  });
} else {
  _flutterFFmpeg
      .execute("-i $videoPath -vcodec libx265 -crf 28 $outputVideo")
      .then((rc) => print("FFmpeg process exited with rc $rc"));

  setState(() {
    videoPath = outputVideo;
  });
}

提前致谢....