如何使用 FFMPEG 将视频文件转换为音频文件？

Question

I'm making video to audio converter app but need help to convert video to audio using ffmpeg. I checked many answers and websites but their answers are not easy to understand and I'm confused with command that is used to convert. What is the proper command to convert video to audio and is I'm executing the command in right way?

public class VideoConvertActivity extends AppCompatActivity {

    private VideoView videoView;
    private Button convertButton;
    private String filePath;
    private FFmpeg ffmpeg;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_video_convert);

        videoView = findViewById(R.id.videoviewID);
        convertButton = findViewById(R.id.convertbuttonID);

        ffmpeg = FFmpeg.getInstance(VideoConvertActivity.this);

// in variable video i'm getting the path of video path from previous activity through intent and that video will have to convert to audio file
        Intent extras = getIntent();
        final String video = extras.getStringExtra("video");

        videoView.setVideoPath(video);
        videoView.start();

        convertButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                try {

                    File moviesDir = Environment.getExternalStoragePublicDirectory(
                            Environment.DIRECTORY_MUSIC
                    );

                    String filePrefix = "convert_audio";
                    String fileExtn = ".mp3";
                    File dest = new File(moviesDir, filePrefix + fileExtn);

                    int fileNo = 0;
                    while (dest.exists()) {
                        fileNo++;
                        dest = new File(moviesDir, filePrefix + fileNo + fileExtn);
                    }
                    filePath = dest.getAbsolutePath();

                    // to execute "ffmpeg -version" command you just need to pass "-version"
                    String[] command = {"-y", "-i", video, "-vn", "-ar", "44100", "-ac", "2", "-b:a", "256k", "-f", "mp3", filePath};
                    ffmpeg.execute(command, new ExecuteBinaryResponseHandler() {

                        @Override
                        public void onStart() {
                            Toast.makeText(VideoConvertActivity.this,"Started",Toast.LENGTH_LONG).show();
                        }

                        @Override
                        public void onProgress(String message) {
                            Toast.makeText(VideoConvertActivity.this,"Progress",Toast.LENGTH_LONG).show();
                        }

                        @Override
                        public void onFailure(String message) {
                            Toast.makeText(VideoConvertActivity.this,"Failed",Toast.LENGTH_LONG).show();
                        }

                        @Override
                        public void onSuccess(String message) {
                            Toast.makeText(VideoConvertActivity.this,"Succeed",Toast.LENGTH_LONG).show();
                        }

                        @Override
                        public void onFinish() {
                            Toast.makeText(VideoConvertActivity.this,"Finished",Toast.LENGTH_LONG).show();
                        }
                    });
                } catch (FFmpegCommandAlreadyRunningException e) {
                    // Handle if FFmpeg is already running
                }

                 Toast.makeText(VideoConvertActivity.this,"Converted Successfully",Toast.LENGTH_SHORT).show();

            }
        });

    }

}

Answer 1

我在清单中授予了读取权限，但忘记授予写入权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Answer 2

Main is not a place u should place a while loop, it will cause problems.Since main is a loop in it self u should use thread to do something in background and not interrupt the flow of program. In this case if will do.

Here is an example of player so u can understand how it works: https://developer.android.com/guide/topics/media/exoplayer

If u don't solve it in a few hours ill see what I can do to help you.

Answer 3

any convert commend you should place it in your command variable

so instrad of this commend

String[] command = {"-y", "-i", video, "-vn", "-ar", "44100", "-ac", "2", "-b:a", "256k", "-f", "mp3", filePath};

use this one

ffmpeg -i video.mp4 -f mp3 -ab 192000 -vn music.mp3

or you can format your commend as you did for command to be an array :

   String[] command = {"-y", "-i", video, "-f", "mp3", "-ab", "192000", "-vn", filePath};