Do I need to run MediaPlayer in a service in Android Studio?

The following code is from the project .

Maybe it's a long time operation when I use the MediaRecorder control, so the author run MediaRecorder in a service, you can see Code B.

Maybe it's a long time operation to play a audio too, so I think the author should run MediaPlayer in a service, but why doesn't Code A do that?

Code A

public final class MediaPlayerHolder implements PlayerAdapter {

    public static final int PLAYBACK_POSITION_REFRESH_INTERVAL_MS = 1000;

    private MediaPlayer mMediaPlayer;
    
    @Override
    public void play() {
        if (mMediaPlayer != null && !mMediaPlayer.isPlaying()) {
            mMediaPlayer.start();
            if (mPlaybackInfoListener != null) {
                mPlaybackInfoListener.onStateChanged(PlaybackInfoListener.State.PLAYING);
            }
            startUpdatingCallbackWithPosition();
        }
    }
    ...
}

Code B

public class RecordingService extends Service {
    
    public class LocalBinder extends Binder {
        public RecordingService getService() {
            return RecordingService.this;
        }
    }

    @Override
    public IBinder onBind(Intent intent) {
        return myBinder;
    }

 
    public void startRecording(int duration) {
        setFileNameAndPath();
        mRecorder = new MediaRecorder();
        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
        mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
        mRecorder.setOutputFile(mFilePath);

        mRecorder.setMaxDuration(duration); // set the max duration, after which the Service is stopped
        mRecorder.setAudioChannels(1);
        mRecorder.setAudioSamplingRate(44100);
        mRecorder.setAudioEncodingBitRate(192000);

       ...
    }

}

from Do I need to run MediaPlayer in a service in Android Studio?