Android自定义视频录制与播放 不错的文章，来不及看，先收藏了

转自http://www.bg135.com/android-custom-video-recorder-play.html

Android系统提供了调用系统录像的功能，我们也可以通过指定一些参数来做一定的刻制化操作，
例如：我们可以指定参数MediaStore.EXTRA_VIDEO_QUALITY设定视频的质量，当前可以的值为0(低质量，176 x 144分辨率)，1(高质量，如1080p (1920 x 1080)分辨率)，
通过设置参数MediaStore.EXTRA_DURATION_LIMIT限定录制时间，
或者通过设置参数MediaStore.EXTRA_SIZE_LIMIT限定录制视频大小。实现代码如下：

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Intent intent =newIntent(MediaStore.ACTION_VIDEO_CAPTURE);

intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY,2);// CamcorderProfile.get(0,CamcorderProfile.QUALITY_LOW);

//intent.putExtra(MediaStore.EXTRA_DURATION_LIMIT, 5);

intent.putExtra(MediaStore.EXTRA_SIZE_LIMIT,VIDEO_MAX_SIZE);

startActivityForResult(intent, TAKE_VIDEO);

然而我们发现通过这种方式录制视频，不仅无法进行深度的刻制化，例如不能录制自定义的视频分辨率(320×240),也不能通过参数去设定白平衡，录像模式，自动对焦，开启闪光灯等等。
而且我们测试发现，就连传入的参数MediaStore.EXTRA_DURATION_LIMIT，MediaStore.EXTRA_SIZE_LIMIT也不是所有机型都能接收，也就是说，即使你限制了只录制5秒钟的视频，但超过时间视频仍然可以录制，
或者说你限制了只录制2M的视频，但当视频超过规定大小后，视频仍然在录制，直至用户停止或撑爆整个存储空间，

基于以上的事实，为了对录制视频深度的刻制化，解决手机平台间导致的差异，以下是我们本章的主题，自定义视频录制，以及解决视频花屏，视频倒转的问题。

在开始录制之前需要进行预览，视频的录制是通过SurfaceView来进行界面的渲染，要想使用SurfaceView，我们首先要获取到SurfaceHolder，在SurfaceView所在的窗口可见的时候，Surface将会被创建，
你可以通过以下代码获取SurfaceHolder的创建和销毁：

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     SurfaceHolder holder = mSurfaceview.getHolder();

holder.addCallback(videoRecorderSurfaceCallBck);

holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

 

SurfaceHolder.Callback videoRecorderSurfaceCallBck=newSurfaceHolder.Callback() {

 

    @Override

    publicvoidsurfaceDestroyed(SurfaceHolder holder) {

        // TODO Auto-generated method stub

        Log.d(TAG,"surfaceDestroyed 将mVideoRecoderSurfaceHolder置空");

        mVideoRecoderSurfaceHolder =null;

    }

 

    @Override

    publicvoidsurfaceCreated(SurfaceHolder holder) {

        // TODO Auto-generated method stub

 

    }

 

    @Override

    publicvoidsurfaceChanged(SurfaceHolder holder,intformat, int width,

            intheight) {

        // TODO Auto-generated method stub

        Log.v(TAG,"surfaceChanged width: "+width+" , height: "+height);

        if(holder.getSurface() ==null) {

            Log.d(TAG,"holder.getSurface() == null");

            return;

        }

        Log.d(TAG,"surfaceChanged 重新给mVideoRecoderSurfaceHolder赋值");

        mVideoRecoderSurfaceHolder = holder;

 

        if(!playFlag){

            if(mPausing) {

                // We're pausing, the screen is off and we already stopped

                // video recording. We don't want to start the camera again

                // in this case in order to conserve power.

                // The fact that surfaceChanged is called _after_ an onPause appears

                // to be legitimate since in that case the lockscreen always returns

                // to portrait orientation possibly triggering the notification.

                return;

            }

 

            // The mCameraDevice will be null if it is fail to connect to the

            // camera hardware. In this case we will show a dialog and then

            // finish the activity, so it's OK to ignore it.

            if(camera ==null)return;

 

            // Set preview display if the surface is being created. Preview was

            // already started.

            if(holder.isCreating()) {

                setPreviewDisplay(holder);

            }else{

                stopVideoRecording();

                restartPreview();

            }

        }else{

            playForPlayUsefulness();

 

        }

    }

};

在获取到SurfaceHolder之后，可以设定预览显示的SurfaceHolder：

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       privatevoidsetPreviewDisplay(SurfaceHolder holder) {

   try{

       camera.setPreviewDisplay(holder);

   }catch(Throwable ex) {

       closeCamera();

       thrownewRuntimeException("setPreviewDisplay failed", ex);

   }

}

在这个方法调用的时候，SurfaceHolder必须已经包含有surface，这个方法必须在startPreview()之前调用，如果预览的surface没有设或设置为null,则会报异常。

之后可以根据需要设定摄像机的一些参数，例如：设定预览大小，帧特率，旋转角度，白平衡，GPS坐标，录制模式，自动对焦等等。代码如下：

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privatevoidsetCameraParameters() {

        mParameters = camera.getParameters();

 

        mParameters.setPreviewSize(VIDEO_WIDTH, VIDEO_HEIGHT);

        mParameters.setPreviewFrameRate(mProfile.videoFrameRate);

        mParameters.setRotation(90);

 

        camera.setParameters(mParameters);

        // Keep preview size up to date.

        mParameters = camera.getParameters();

}

这里先通过方法camera.getParameters()获取摄像机原先的一些配置信息，如果这里进行了修改，则必须再次调用setParameters方法才能使得参数生效。
经过以上准备工作之后可以启动视图预览：

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try{

        camera.startPreview();

            mPreviewing =true;

        }catch(Throwable ex) {

            closeCamera();

            thrownewRuntimeException("startPreview failed", ex);

        }

此时你可以实时看到摄像机获取的图像，当然你可以左右、前后移动设备感受下录制的效果，在你需要的时候启动录制按钮，
在录制之前需要做些准备工作，首先需要初始化MediaRecorder对象，停止先前的预览，同时释放camera的锁定，使得MediaRecorder可以获得对camera的使用，

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mMediaRecorder =newMediaRecorder();

 

        // Unlock the camera object before passing it to media recorder.

        camera.stopPreview();

        camera.unlock();

接下来是设定MediaRecorder录制视频的一些属性，视频的一些参数完全可以进行自定义，只要你非常精通这些参数之间的相互关系，不然很容易出现各种异常情况，
这里我们可以通过MediaRecorder的一些SET方法进行参数的自定义。

当然你也可以完全使用系统预设定的视频参数，可以通过以下代码获取：

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@TargetApi(9)

    privatevoidreadVideoPreferences() {

        mProfile = CamcorderProfile.get(0,CamcorderProfile.QUALITY_LOW);//240X320

    }

get方法传入的第一个参数是摄像头的ID号，0为后置摄像头，1为前置摄像头。第二个参数是系统与设定的视频参数ID，即视频的质量等级，其中QUALITY_LOW，QUALITY_HIGH是所有系统一定都含有的，
然而其他的视频等级QUALITY_480P，QUALITY_QVGA等并不是所有系统都包含有的。这些视频的质量等级均包含有设定好的参数值，例如：音视频编码，音视频比特率，音视频采样率，视频帧的宽高，声道以及录制视频长度等等。

这里我们采取的策略是一部分采用系统自定义的参数，一部分参数进行刻制化，代码如下：

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mMediaRecorder.setCamera(camera);

//      mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);

        mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);

//      mMediaRecorder.setProfile(mProfile);

 

//  mMediaRecorder.setOrientationHint(90);

    mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);

 

        /*mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);

    mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);

    mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);

    mMediaRecorder.setAudioEncodingBitRate(AUDIO_ENCODE_BIT_RATE);

    mMediaRecorder.setVideoEncodingBitRate(VIDEO_ENCODE_BIT_RATE);

    mMediaRecorder.setVideoSize(VIDEO_WIDTH, VIDEO_HEIGHT);

    mMediaRecorder.setAudioChannels(2);*/

 

    mProfile.fileFormat=MediaRecorder.OutputFormat.MPEG_4;

    mProfile.videoCodec=MediaRecorder.VideoEncoder.H264;

    mProfile.audioCodec=MediaRecorder.AudioEncoder.AAC;

    mProfile.videoFrameHeight=VIDEO_HEIGHT;

    mProfile.videoFrameWidth=VIDEO_WIDTH;

 

    mMediaRecorder.setProfile(mProfile);

 

    mMediaRecorder.setOrientationHint(90);

 

//  mMediaRecorder.setVideoSize(VIDEO_WIDTH, VIDEO_HEIGHT);

 

    mMediaRecorder.setMaxDuration(RECORDER_TIME);

 

        if(mVideoDirectory.exists() ==false)

        mVideoDirectory.mkdirs();

 

    createVideoPath();

    // mMediaRecorder.setOutputFile("sdcard/1.mp4");

    mMediaRecorder.setOutputFile(mVideoFilename);

 

//      mMediaRecorder.setPreviewDisplay(mSurfaceHolder.getSurface());

        mMediaRecorder.setPreviewDisplay(mVideoRecoderSurfaceHolder.getSurface());// 这个方法无须调用 ????

参数设定好以后，就可以进入prepare生命周期，

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try{

            mMediaRecorder.prepare();

        }catch(IOException e) {

            Log.i(TAG,"initializeRecorder e="+e);

            releaseMediaRecorder();

            thrownewRuntimeException(e);

        }

参数设定的时候需要注意的是，有些参数的设定会有一些顺序的要求，例如：setOutputFile的参数设定必须在setOutputFormat参数设定之前，
几乎所有参数的设定都必须在prepare方法之前，同时prepare方法必须在start方法之前。

在一切初始化工作完成之后，可以放心的启动start方法，代码如下：

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try{

            mMediaRecorder.start();// Recording is now started

        }catch(RuntimeException e) {

            Log.e(TAG,"Could not start media recorder. ", e);

            releaseMediaRecorder();

            return;

        }

至此录制视频真正的开始，在录制的时候，我们可以进行一些信息显示或UI的更新，例如：我们这里实时显示当前录制的时间，以及根据需要进行UI的隐藏与显示。

在录制超过我们设定的一些限制，例如：时间或大小等，或在录制发生了异常情况，此时我们都应该及时停止视频录制：

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privatevoidstopVideoRecording() {

        Log.v(TAG,"stopVideoRecording");

        first_time_record =false;

        if(mMediaRecorderRecording) {

            mMediaRecorder.setOnErrorListener(null);

            mMediaRecorder.setOnInfoListener(null);

            try{

                mMediaRecorder.stop();

                mCurrentVideoFilename = mVideoFilename;

                Log.v(TAG,"Setting current video filename: "

                        + mCurrentVideoFilename);

 

             // Add the Video to the media store

                MediaScannerConnection.scanFile(this,

                        newString[] { mCurrentVideoFilename},

                        newString[] {null},

                        newOnScanCompletedListener() {

                @Override

                publicvoidonScanCompleted(String path, Uri uri) {

                    // TODO Auto-generated method stub

                    Log.v(TAG,"扫描完成: "

                            + path+" ,uri"+uri);

                }

            });

            }catch(RuntimeException e) {

                Log.e(TAG,"stop fail: "+ e.getMessage());

                deleteVideoFile(mVideoFilename);

            }

            mMediaRecorderRecording =false;

            updateRecordingIndicator(false);

            timer.setVisibility(View.GONE);// ？？？

 

            keepScreenOnAwhile();

            mVideoFilename =null;

        }

        releaseMediaRecorder(); // always release media recorder

    }

一旦录制停止，你必须重新配置它，就像刚创建的时候，值得注意的是，如果在调用该方法前无有效的音/视频文件，则会报RuntimeException的异常，这个很容易发生在当执行完start()方法后立即执行stop()方法，
当这个异常发生的时候，应用可以采取相应的措施去清楚输出文件(例如：删除输出文件)，因为当这个异常发生的时候，输出文件没有正确生成。

这里我们还加入了扫描文件的功能方法，使得录制的视频能及时被系统读取入媒体库，

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// Add the Video to the media store

        MediaScannerConnection.scanFile(this,

                newString[] { mCurrentVideoFilename},

                newString[] {null},

                newOnScanCompletedListener() {

            @Override

            publicvoidonScanCompleted(String path, Uri uri) {

                // TODO Auto-generated method stub

                Log.v(TAG,"扫描完成: "

                        + path+" ,uri"+uri);

            }

        });

停止录制之后更重要的工作是及时释放MediaRecorder以及Camera所引用的资源：

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privatevoidreleaseMediaRecorder() {

        Log.v(TAG,"Releasing media recorder.");

        if(mMediaRecorder !=null) {

            cleanupEmptyFile();

            mMediaRecorder.reset();

            mMediaRecorder.release();

            mMediaRecorder =null;

        }

        // Take back the camera object control from media recorder. Camera

        // device may be null if the activity is paused.

        if(camera !=null) {

            camera.lock();

            camera.release();

            camera=null;

        }

    }

到此，整个视频的录制过程就结束了，如果在视频存放的目录找到了对应的视频，那么恭喜你成功了。
这个Demo不仅可以录制视频，还能在当前界面实时播放录制的视频，其播放使用的是MediaPlayer API，使用的过程和播放音乐的大致相同，
同样我们首先要初始化MediaPlayer的对象，以及设定一些监听回调方法，代码如下：

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/**

     * Makes sure the media player exists and has been reset. This will create the media player

     * if needed, or reset the existing media player if one already exists.

     */

    voidcreateMediaPlayerIfNeeded() {

        if(player ==null) {

            player =newMediaPlayer();

 

            // Make sure the media player will acquire a wake-lock while playing. If we don't do

            // that, the CPU might go to sleep while the song is playing, causing playback to stop.

            //

            // Remember that to use this, we have to declare the android.permission.WAKE_LOCK

            // permission in AndroidManifest.xml.

            player.setWakeMode(getApplicationContext(), PowerManager.PARTIAL_WAKE_LOCK);

 

            // we want the media player to notify us when it's ready preparing, and when it's done

            // playing:

            player.setOnPreparedListener(this);

            player.setOnCompletionListener(this);

            player.setOnErrorListener(this);

        }

        else

            player.reset();

    }

初始化完成后，设定播放的视频源以及用于显示的SurfaceHolder等。同时启动异步prepare:

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privatevoidplayVideo(){

 

        createMediaPlayerIfNeeded();

        try{

//          Log.v(TAG, "mSurfaceHolder==null: " + (mSurfaceHolder==null));

            Log.v(TAG,"mVideoPlaySurfaceHolder==null: "+ (mVideoPlaySurfaceHolder==null));

            player.setDataSource(HereTalkCamera.this,Uri.parse(mCurrentVideoFilename));

//          player.setDisplay(mSurfaceHolder);

            player.setDisplay(mVideoPlaySurfaceHolder);

            player.setAudioStreamType(AudioManager.STREAM_MUSIC);

            player.setScreenOnWhilePlaying(true);

 

            // starts preparing the media player in the background. When it's done, it will call

            // our OnPreparedListener (that is, the onPrepared() method on this class, since we set

            // the listener to 'this').

            //

            // Until the media player is prepared, we *cannot* call start() on it!

            player.prepareAsync();

        }catch(IOException e){

            // TODO Auto-generated catch block

            Log.v(TAG,"playVideo IOException: "+ e);

            e.printStackTrace();

        }

    }

在异步prepare完成之后，我们在回调方法onPrepared中可以执行一些播放相关的操作：

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@Override

    publicvoidonPrepared(MediaPlayer mp) {

        // TODO Auto-generated method stub

        Log.v(TAG,"onPrepared: ");

 

        setVideoLengthSize(getTimeString(Math.round(player.getDuration()/1000)));

 

        intmVideoWidth = mp.getVideoWidth();

        intmVideoHeight = mp.getVideoHeight();

        Log.v(TAG,"onPrepared mVideoWidth: "+mVideoWidth+" , mVideoWidth: "+mVideoHeight);

 

//      mSurfaceview.getHolder().setFixedSize(mVideoWidth, mVideoHeight);

 

        configAndStartMediaPlayer();

        mRecordingStartTime = SystemClock.uptimeMillis();

        /*play_time = new myCountDownTimer(player.getDuration(), 500, 0);

        play_time.start();*/

        updateRecordingTime();

    }

 

     /**

     * Reconfigures MediaPlayer according to audio focus settings and starts/restarts it. This

     * method starts/restarts the MediaPlayer respecting the current audio focus state. So if

     * we have focus, it will play normally; if we don't have focus, it will either leave the

     * MediaPlayer paused or set it to a low volume, depending on what is allowed by the

     * current focus settings. This method assumes mPlayer != null, so if you are calling it,

     * you have to do so from a context where you are sure this is the case.

     */

    voidconfigAndStartMediaPlayer() {

            Log.v(TAG,"player.isPlaying(): "+ player.isPlaying());

            if(player.isPlaying()) {

                player.pause();

                mMediaPlaying=false;

            }else{

                player.start();

                mMediaPlaying=true;

            }

    }

需要注意的是，这里我们setDisplay方法传入的并不是视频录制时候的mSurfaceHolder，而是视频播放专用的mVideoPlaySurfaceHolder，
其原因在于，如果共用同一个，则会出现花屏的异常，更多详细解读请阅读文章：《Android自定义视频录制问题总结》

在视频播放完成或任何异常发生后，一个好的习惯是及时释放MediaPlayer所引用的相关资源：

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privatevoidreleaseMediaplayer(){

            Log.v(TAG,"releaseMediaplayer(): ");

        if(player!=null){

            player.reset();

            player.release();

            player =null;

        }

        mMediaPlaying=false;

    }

最后别忘了在Manifest.xml文件中加入权限：
<uses-permission android:name=”android.permission.RECORD_AUDIO”/>
<uses-permission android:name=”android.permission.MODIFY_AUDIO_SETTINGS”/>
<uses-permission android:name=”android.permission.WAKE_LOCK”/>
<uses-permission android:name=”android.permission.WRITE_EXTERNAL_STORAGE” />
<uses-permission android:name=”android.permission.CAMERA”/>