在 Android 中使用 MediaRecorder API 代替 Intent 进行相机录制

Question

I'm using the following code to record the camera in Android that uses the basic Intent . How can I change it to use MediaRecorder API instead of this Intent-based approach?

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

I don't use the Android SDK (my Java skills are on Windows only), but from a quick research...

See if this tutorial helps you (more info further beow)...
Just replace their audio setup (3GP) with the H264 & AAC setup from the other Question .
Also read the section about "Recording Video" on this article to understand the needed parts.

Also declare permissions in your Manifest.xml. An example of such manifest and related code is here on Github (that one allows RECORD_AUDIO but you need also a RECORD_VIDEO so set as):

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

Back to the tutorial, I cannot test their code but something like the below edit should get you started:

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

Then inside that class you add useful functions (initialise Recorder, start rec, stop rec, save file)...

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();
}

So to begin a recording, just inititalise the media recorder and do a recorder.start(); to begin recording (camera and mic are used automatically according to your MediaRecorder settings).