3.27

安卓应用中的音视频处理实战​
在多媒体应用需求日益增长的当下，掌握安卓中的音视频处理技术至关重要。Android 提供了 MediaPlayer、MediaRecorder 等核心类用于音频和视频的播放与录制。​

1. 音频播放与录制​
   使用 MediaPlayer 播放音频文件：​
   ​
   MediaPlayer mediaPlayer = new MediaPlayer();​
   try {​
   mediaPlayer.setDataSource(context, Uri.parse("android.resource://" + context.getPackageName() + "/" + R.raw.audio_file));​
   mediaPlayer.prepare();​
   mediaPlayer.start();​
   } catch (IOException e) {​
   e.printStackTrace();​
   }​
   ​
   使用 MediaRecorder 录制音频：​
   ​
   MediaRecorder mediaRecorder = new MediaRecorder();​
   mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);​
   mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);​
   mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);​
   mediaRecorder.setOutputFile(Environment.getExternalStorageDirectory() + "/recorded_audio.3gp");​
   try {​
   mediaRecorder.prepare();​
   mediaRecorder.start();​
   } catch (IOException e) {​
   e.printStackTrace();​
   }​
   ​
2. 视频播放与录制​
   使用 VideoView 播放视频：​
   ​
   <VideoView​
   android:id="@+id/video_view"​
   android:layout_width="match_parent"​
   android:layout_height="match_parent"/>​
   ​
   ​
   VideoView videoView = findViewById(R.id.video_view);​
   videoView.setVideoURI(Uri.parse("android.resource://" + getPackageName() + "/" + R.raw.video_file));​
   videoView.setMediaController(new MediaController(this));​
   videoView.requestFocus();​
   videoView.start();​
   ​
   使用 MediaRecorder 录制视频：​
   ​
   MediaRecorder mediaRecorder = new MediaRecorder();​
   mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);​
   mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);​
   mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);​
   mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);​
   mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);​
   mediaRecorder.setOutputFile(Environment.getExternalStorageDirectory() + "/recorded_video.mp4");​
   try {​
   mediaRecorder.prepare();​
   mediaRecorder.start();​
   } catch (IOException e) {​
   e.printStackTrace();​
   }​