使用MediaRecorder录制MPEG

Question

我正在尝试录制mpeg2-ts视频，以便使用Android MediaRecorder类将其流式传输到server / socket，如here所述……

代码如下：

public class MediaRecorderDemo extends Activity
{
private final static String TAG = "MediaRecorderDemo";
Camera camera;
CameraPreview cameraPreview;
MediaRecorder mediaRecorder;
File outputFile = new File(Environment.getExternalStorageDirectory().getPath() + "/out1.ts");

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.media_recorder_demo_layout);

    camera = getCameraInstance();
    cameraPreview = new CameraPreview(this);
    FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
    preview.addView(cameraPreview);
}

private Camera getCameraInstance()
{
    final String FUNCTION = "getCameraInstance";

    Camera c = null;
    try
    {
        c = Camera.open();
    }
    catch(Exception e)
    {
        Log.e(TAG, FUNCTION + " : " + e.getMessage());
    }

    return c;
}

void initMediaRecorder()
{
    final String FUNCTION = "initMediaRecorder";
    FileDescriptor outputFileFD = null;
    try
    {
        outputFile.createNewFile();
        outputFileFD = new FileOutputStream(outputFile).getFD();
    }
    catch(Exception e)
    {
        Log.e(TAG, FUNCTION + " : " + e.getMessage());
    }

    mediaRecorder = new MediaRecorder();
    mediaRecorder.setOnErrorListener(new MediaRecorder.OnErrorListener() {
        final static String TAG = "MediaRecorder.onErrorListener";

        @Override
        public void onError(MediaRecorder mr, int what, int extra) {
            Log.e(TAG, "Error : " + what + " " + extra);
        }
    });

    camera.unlock();
    mediaRecorder.setPreviewDisplay(cameraPreview.getHolder().getSurface());
    mediaRecorder.setCamera(camera);
    mediaRecorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
    mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
    //mediaRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_LOW));
    mediaRecorder.setOutputFormat(8);
    Log.d(TAG, "File Exists : " + outputFile.exists());
    mediaRecorder.setOutputFile(outputFileFD);
    mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
    mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
    //mediaRecorder.setVideoSize(640, 480);
    mediaRecorder.setMaxDuration(-1);
    //mediaRecorder.setVideoFrameRate(16);
    mediaRecorder.setVideoEncodingBitRate(1024 * 1024);

    try
    {
        mediaRecorder.prepare();
        Log.d(TAG, "MediaRecorder Prepared.");
        mediaRecorder.start();

    }
    catch(Exception e)
    {
        Log.e(TAG, FUNCTION + " : " + e.getMessage());
        //releaseMediaRecorder();
    }
}

void releaseMediaRecorder()
{
    final String FUNCTION = "releaseMediaRecorder";

    try
    {
        if(mediaRecorder != null)
        {
            mediaRecorder.stop();
            mediaRecorder.reset();
            mediaRecorder.release();
            mediaRecorder = null;
            camera.lock();
        }
    }

    catch(Exception e)
    {
        Log.e(TAG, FUNCTION + " : " + e.getMessage());
    }
}

void releaseCamera()
{
    final String FUNCTION = "releaseCamera";
    try
    {
        if(camera != null)
        {
            camera.stopPreview();
            camera.release();
        }
        camera = null;
    }
    catch(Exception e)
    {
        Log.e(TAG, FUNCTION + " : " + e.getMessage());
    }
}

@Override
public void onStart()
{
    super.onStart();
}

@Override
public void onPause()
{
    super.onPause();
}

@Override
public void onResume()
{
    super.onResume();
}

@Override
public void onStop()
{
    super.onStop();
}

@Override
public void onDestroy()
{
    super.onDestroy();
}

public class CameraPreview extends SurfaceView
{
    private final static String TAG = "CameraPreview"; 
    SurfaceHolder holder;
    boolean isPreviewDisplaySet;

    public CameraPreview(Context context)
    {
        this(context, (AttributeSet)null);

        this.holder = getHolder();
        this.holder.addCallback(new SurfaceHolderCallback());
    }

    public CameraPreview(Context context, AttributeSet attrSet)
    {
        this(context, attrSet, 0);
    }

    public CameraPreview(Context context, AttributeSet attrSet, int defStyle)
    {
        super(context, attrSet, defStyle);
    }

    private void releaseCamera()
    {
        if(camera != null)
        {
            camera.release();
            camera = null;
        }
    }

    private class SurfaceHolderCallback implements SurfaceHolder.Callback
    {
        @Override
        public void surfaceCreated(SurfaceHolder holder)
        {
            final String FUNCTION = "surfaceCreated";
            Log.d(TAG, "Surface Created.");

            try
            {
                camera.setPreviewDisplay(holder);
                camera.startPreview();

                initMediaRecorder();
                //mediaRecorder.start();
            }
            catch(Exception e)
            {
                Log.e(TAG, FUNCTION + " : " + e.getMessage());
            }
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder)
        {
            final String FUNCTION = "surfaceDestroyed";
            Log.d(TAG, "Surface Destroyed.");

            try
            {
                releaseMediaRecorder();
                releaseCamera();
            }
            catch(Exception e)
            {
                Log.e(TAG, FUNCTION + " : " + e.getMessage());
            } 
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int w, int h)
        {
            final String FUNCTION = "surfaceChanged";
            Log.d(TAG, "Surface Changed.");

            if(holder.getSurface() == null)
                return;

            try
            {
                camera.stopPreview();
            }
            catch(Exception e)
            {
                Log.e(TAG, FUNCTION + " : " + e.getMessage());
            }

            try
            {
                camera.setPreviewDisplay(holder);
                camera.startPreview();
            }
            catch(Exception e)
            {
                Log.e(TAG, FUNCTION + " : " + e.getMessage());
            }
        }
    }
}
}

调用mediaRecorder.prepare()和mediaRecorder.start()时不会出现任何错误，并显示相机预览...但过了一段时间，预览被切断，然后屏幕冻结，在输出路径上创建了一个空文件……这个问题在Android Issue List上也有报道，但尚未得到纠正...

我曾尝试在Galaxy Note N7000和三星Galaxy Tab2 P3100上运行相同的应用程序，但在自定义安卓4.2 ROM...So上，它似乎与只读存储器或特定的硬件配置无关。

如果我错过了什么或做错了什么，我会很高兴，当然也会松一口气……？

谢谢..。

Answer 1

解决方案是在M2ts Writer中应用补丁。构建libstagefright.so并推送到设备。在应用程序中也设置如下

recorder.setAudioSamplingRate(48000); 
recorder.setAudioEncodingBitRate(128000);

否则它将不会完整地录制该剪辑。不过，我并没有深入研究设置上述参数的原因。

libstagefright中M2tsWriter的修补程序

diff --git a/media/libstagefright/MPEG2TSWriter.cpp b/media/libstagefright/MPEG2TSWriter.cpp

index c9ed5bb..a42371f 100644

--- a/media/libstagefright/MPEG2TSWriter.cpp

+++ b/media/libstagefright/MPEG2TSWriter.cpp

@@ -411,6 +411,7 @@ void MPEG2TSWriter::SourceInfo::onMessageReceived(const sp<AMessage> &msg) { 
                            (const uint8_t *)buffer->data() 
                             + buffer->range_offset(), 
                            buffer->range_length()); 
+                    readMore(); 
                 } else if (buffer->range_length() > 0) {
                     if (mStreamType == 0x0f) { 
                         if (!appendAACFrames(buffer)) { 

Answer 2

我遇到了和你类似的问题，虽然不是在同一个设备上。根据我的初步调查，在录制mpeg ts时，HAL中摄像头的记录堆(缓冲区)没有正确释放。但我仍然不太确定yuv data是否已经到达OMX。高级原因应由每个硬件供应商检查。希望能有所帮助。:)