在 Android 中使用 MediaRecorder API 而不是 Intent 进行摄像头录制

Question

我正在使用以下代码在使用基本Intent 的 Android 中记录相机。如何将其更改为使用 MediaRecorder API 而不是这种基于 Intent 的方法？

private Uri fileUri;
//...
        private void recordVideo() {
            Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
            fileUri = getOutputMediaFileUri(MEDIA_TYPE_VIDEO);
            // set video quality
            intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri); // set the image file
    
            // start the video capture Intent
            startActivityForResult(intent, CAMERA_CAPTURE_VIDEO_REQUEST_CODE);
        }
    
    // ...
    
    @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == CAMERA_CAPTURE_IMAGE_REQUEST_CODE && resultCode == RESULT_OK) {
                // play the video given the global fileUri 
    }

Answer 1

我不使用 Android SDK（我的 Java 技能仅适用于 Windows），但通过快速研究...

看看this tutorial 是否对您有帮助（更多信息请见下文）...
只需使用来自other Question 的 H264 和 AAC 设置替换他们的音频设置 (3GP)。
另请阅读this article 上关于“录制视频”的部分以了解所需部分。

还有 declare permissions 在您的 Manifest.xml 中。这种清单和相关代码的一个示例是here on Github（允许RECORD_AUDIO，但您还需要一个RECORD_VIDEO，因此设置为）：

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

回到教程，我无法测试他们的代码，但下面的编辑应该可以帮助你开始：

public class MainActivity extends Activity 
{  
    MediaRecorder recorder;  
    File outputfile = null;  
    static final String TAG = "MediaRecording"; 

然后在该类中添加有用的功能（初始化记录器、启动记录、停止记录、保存文件）...

public void initRecording(View view) throws IOException 
{  
    //Creating file  
    File dir = Environment.getExternalStorageDirectory();  
    try { outputfile = File.createTempFile("video_test_android", ".mp4", dir); } 
    catch (IOException e) 
    {  
      Log.e(TAG, "external storage access error");  
      return;  
    }  
    
     //# Create a new instance of MediaRecorder
    recorder = new MediaRecorder(); //create MediaRecorder object
    recorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
    recorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
    recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);

    //# Video settings
    recorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264); //contained inside MP4
    recorder.setVideoSize(640, 480); //width 640, height 480
    recorder.setVideoFrameRate(30);  //30 FPS
    recorder.setVideoEncodingBitRate(3000000); //adjust this for picture quality

    //# Audio settings
    recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC); //must always be AAC
    recorder.setAudioEncoder(MediaRecorder.getAudioSourceMax());
    recorder.setAudioEncodingBitRate(16);
    recorder.setAudioSamplingRate(44100);

    recorder.setOutputFile(outputfile.getAbsolutePath());  
    recorder.prepare();  
    
} 

public void startRecording(View view)
{
    recorder.start();
} 

public void stopRecording(View view)
{
    recorder.stop(); recorder.release(); 

    //# After stopping the recorder...
    //# Create the video file and add it to the Media Library.  
    addRecordingToMediaLibrary();
 
}

protected void addRecordingToMediaLibrary() 
{
    //# used to store a set of values that the ContentResolver can process
    ContentValues values = new ContentValues(4); //# 4 items (title, date, etc)

    long current = System.currentTimeMillis(); //# get recording time (date)

    //# size of 4 for values, all in String
    values.put(MediaStore.Audio.Media.TITLE, "Android Tina J - " + outputfile.getName());
    values.put(MediaStore.Audio.Media.DATE_ADDED, (int) (current / 1000));
    values.put(MediaStore.Audio.Media.MIME_TYPE, "video/mp4"); //# set MIME type
    values.put(MediaStore.Audio.Media.DATA, outputfile.getAbsolutePath()); // data stream for the file

    //# provides applications access to the content model
    ContentResolver contentResolver = getContentResolver();

    //# The content:// style URI for the "primary" external storage volume.
    Uri base = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Uri newUri = contentResolver.insert(base, values);

    //# Request the media scanner to scan a file and add it to the media database
    sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, newUri));

    //# if you need a notification...
    //Toast.makeText(this, "Created Media File : " + newUri, Toast.LENGTH_LONG).show();
}

所以要开始录制，只需初始化媒体录制器并发送recorder.start(); 即可开始录制（相机和麦克风会根据您的 MediaRecorder 设置自动使用）。