【Android】Android Camera实时数据采集及通过MediaCodec硬编码编码数据的流程

/*    * 编码器获取数据，编码，编码后的数据的处理等大致流程如下：   */  /* 1.获取原始帧 */   @Override  onPreviewFrame( byte[] onPreviewData, Camera camera) {       /* 在此可以对onPreviewData进行Rotate或者Scale       * 也可以转换yuv的格式，例如yuv420P(YV12)或者yuv420SP(NV21/NV12)       * 相关开源类库可以使用libyuv/ffmpeg等       */      getRawFrame(onPreviewData)      /* 然后将onPreviewData加入Camera回调*/      addCallbackBuffer(onPreviewData);  }  private void getRawFrame( byte[] rawFrame ) { encodFrame(rawFrame); }  /* 2.进行编码 */  private byte[] encodFrame(byte[] inputData) { return encodedData; }   /* 3.取得编码后的数据便可进行相应的操作，可以保存为本地文件，也可进行推流 */   Operation ? Send(byte[] sendData) : Save(byte[] saveData) 

上述代码onPreviewFrame为Camera类的接口，使用Camera前需要进行SurfaceView及SurfaceHolder的初始化及相应interface的实现：

// init the preview surface  private void initview() {      SurfaceView surfaceView = (SurfaceView) findViewById(R.id.record_surface);      SurfaceHolder surfaceHolder = surfaceView.getHolder();      surfaceHolder.addCallback(this);      surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);      }      @Override  public void surfaceCreated(SurfaceHolder holder) {      openCamera(holder); // 开启相机  }    @Override  public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {  }    @Override  public void surfaceDestroyed(SurfaceHolder holder) {      releaseCamera(); // 在surfaceDestroyed的时候记得releaseCamera  }    private void openCamera(SurfaceHolder holder) {      releaseCamera();      try {              camera = getCamera(Camera.CameraInfo.CAMERA_FACING_BACK); // 根据需求选择前/后置摄像头          } catch (Exception e) {              camera = null;              if (AppContext.isDebugMode) {                  e.printStackTrace();              }          }      if(mCamera != null){      try {              mCamera.setPreviewCallback(this);              mCamera.setDisplayOrientation(90); // 此方法为官方提供的旋转显示部分的方法，并不会影响onPreviewFrame方法中的原始数据；              if(parameters == null){                  parameters = mCamera.getParameters();              }              parameters.setPreviewFormat(ImageFormat.NV21); // 常用格式：NV21 / YV12              parameters.setPreviewSize(width, height); // 还可以设置很多相机的参数，但是建议先遍历当前相机是否支持该配置，不然可能会导致出错；              mCamera.setParameters(parameters);              mCamera.setPreviewDisplay(holder);              mCamera.startPreview();      } catch (IOException e) {          e.printStackTrace();      }      }  }    @TargetApi(9)  private Camera getCamera(int cameraType) {      Camera camera = null;      try {          camera = Camera.open(cameraType);       } catch (Exception e) {          e.printStackTrace();      }      return camera; // returns null if camera is unavailable  }    private synchronized void releaseCamera() {      if (camera != null) {          try {              camera.setPreviewCallback(null);          } catch (Exception e) {              e.printStackTrace();          }          try {              camera.stopPreview();          } catch (Exception e) {              e.printStackTrace();          }          try {              camera.release();          } catch (Exception e) {              e.printStackTrace();          }          camera = null;      }  }

MediaCodec硬编码实现部分：

// video device.  private Camera camera;  private MediaCodec vencoder;  private MediaCodecInfo vmci;  private MediaCodec.BufferInfo vebi;  private byte[] vbuffer;  // video camera settings.  private Camera.Size vsize;  private int vcolor;  private int vbitrate_kbps = 300;  private final static int VFPS = 20;  private final static int VGOP = 5;  private final static int VWIDTH = 640;  private final static int VHEIGHT = 480;    /* 首先需要初始化MediaCodec的配置 */  private void initMediaCodec() {       // choose the right vencoder, perfer qcom then google.      vcolor = chooseVideoEncoder();      // vencoder yuv to 264 es stream.      // requires sdk level 16+, Android 4.1, 4.1.1, the JELLY_BEAN      try {          vencoder = MediaCodec.createByCodecName(vmci.getName());      } catch (IOException e) {          Log.e(TAG, "create vencoder failed.");          e.printStackTrace();          return;      }      vebi = new MediaCodec.BufferInfo();      // setup the vencoder.      // @see https://developer.android.com/reference/android/media/MediaCodec.html      MediaFormat vformat = MediaFormat.createVideoFormat(MediaFormat.MIMETYPE_VIDEO_AVC, vsize.width, vsize.height);      vformat.setInteger(MediaFormat.KEY_COLOR_FORMAT, vcolor);      vformat.setInteger(MediaFormat.KEY_MAX_INPUT_SIZE, 0);      vformat.setInteger(MediaFormat.KEY_BIT_RATE, 1000 * vbitrate_kbps);      vformat.setInteger(MediaFormat.KEY_FRAME_RATE, VFPS);      vformat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, VGOP);      Log.i(TAG, String.format("vencoder %s, color=%d, bitrate=%d, fps=%d, gop=%d, size=%dx%d",              vmci.getName(), vcolor, vbitrate_kbps, VFPS, VGOP, vsize.width, vsize.height));      // the following error can be ignored:      // 1. the storeMetaDataInBuffers error:      //      [OMX.qcom.video.encoder.avc] storeMetaDataInBuffers (output) failed w/ err -2147483648      //      @see http://bigflake.com/mediacodec/#q12      vencoder.configure(vformat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);      vencoder.start();  }    // for the vbuffer for YV12(android YUV), @see below:  // https://developer.android.com/reference/android/hardware/Camera.Parameters.html#setPreviewFormat(int)  // https://developer.android.com/reference/android/graphics/ImageFormat.html#YV12  private int getYuvBuffer(int width, int height) {      // stride = ALIGN(width, 16)      int stride = (int) Math.ceil(width / 16.0) * 16;      // y_size = stride * height      int y_size = stride * height;      // c_stride = ALIGN(stride/2, 16)      int c_stride = (int) Math.ceil(width / 32.0) * 16;      // c_size = c_stride * height/2      int c_size = c_stride * height / 2;      // size = y_size + c_size * 2      return y_size + c_size * 2;  }    // choose the video encoder by name.  private MediaCodecInfo chooseVideoEncoder(String name, MediaCodecInfo def) {      int nbCodecs = MediaCodecList.getCodecCount();      for (int i = 0; i < nbCodecs; i++) {          MediaCodecInfo mci = MediaCodecList.getCodecInfoAt(i);          if (!mci.isEncoder()) {              continue;          }          String[] types = mci.getSupportedTypes();          for (int j = 0; j < types.length; j++) {              if (types[j].equalsIgnoreCase(VCODEC)) {                  //Log.i(TAG, String.format("vencoder %s types: %s", mci.getName(), types[j]));                  if (name == null) {                      return mci;                  }                    if (mci.getName().contains(name)) {                      return mci;                  }              }          }      }      return def;  }    // choose the right supported color format. @see below:  // https://developer.android.com/reference/android/media/MediaCodecInfo.html  // https://developer.android.com/reference/android/media/MediaCodecInfo.CodecCapabilities.html  private int chooseVideoEncoder() {      // choose the encoder "video/avc":      //      1. select one when type matched.      //      2. perfer google avc.      //      3. perfer qcom avc.      vmci = chooseVideoEncoder(null, null);      //vmci = chooseVideoEncoder("google", vmci);      //vmci = chooseVideoEncoder("qcom", vmci);        int matchedColorFormat = 0;      MediaCodecInfo.CodecCapabilities cc = vmci.getCapabilitiesForType(VCODEC);      for (int i = 0; i < cc.colorFormats.length; i++) {          int cf = cc.colorFormats[i];          Log.i(TAG, String.format("vencoder %s supports color fomart 0x%x(%d)", vmci.getName(), cf, cf));            // choose YUV for h.264, prefer the bigger one.          // corresponding to the color space transform in onPreviewFrame          if ((cf >= cc.COLOR_FormatYUV420Planar && cf <= cc.COLOR_FormatYUV420SemiPlanar)) {              if (cf > matchedColorFormat) {                  matchedColorFormat = cf;              }          }      }      for (int i = 0; i < cc.profileLevels.length; i++) {          MediaCodecInfo.CodecProfileLevel pl = cc.profileLevels[i];          Log.i(TAG, String.format("vencoder %s support profile %d, level %d", vmci.getName(), pl.profile, pl.level));      }      Log.i(TAG, String.format("vencoder %s choose color format 0x%x(%d)", vmci.getName(), matchedColorFormat, matchedColorFormat));      return matchedColorFormat;  }

上述代码为SRS的部分实现，仅作参考。

还推荐一个项目，该项目实现了编码后的数据存为本地.h264文件，方便分析，本人Fork的git地址： https://github.com/eterrao/MediaCodecEncodeH264.git

原作者git地址： https://github.com/sszhangpengfei/MediaCodecEncodeH264.git

（在此感谢拥有开源共享精神的各位朋友，因为你们我才能在学习和成长的路上少了很多坑！）

实际上MediaCodec的实现步骤基本都大同小异，但是请注意在API20以后编码器数据处理的机制有所改变，官方给出的建议如下:

链接： developer.android.com/reference/android/media/MediaCodec.html

以下摘抄官方API：

Depending on the API version, you can process data in three ways:

Asynchronous Processing using Buffers

MediaCodec codec = MediaCodec.createByCodecName(name);   MediaFormat mOutputFormat; // member variable   codec.setCallback(new MediaCodec.Callback() {     @Override     void onInputBufferAvailable(MediaCodec mc, int inputBufferId) {       ByteBuffer inputBuffer = codec.getInputBuffer(inputBufferId);       // fill inputBuffer with valid data       …       codec.queueInputBuffer(inputBufferId, …);     }       @Override     void onOutputBufferAvailable(MediaCodec mc, int outputBufferId, …) {       ByteBuffer outputBuffer = codec.getOutputBuffer(outputBufferId);       MediaFormat bufferFormat = codec.getOutputFormat(outputBufferId); // option A       // bufferFormat is equivalent to mOutputFormat       // outputBuffer is ready to be processed or rendered.       …       codec.releaseOutputBuffer(outputBufferId, …);     }       @Override     void onOutputFormatChanged(MediaCodec mc, MediaFormat format) {       // Subsequent data will conform to new format.       // Can ignore if using getOutputFormat(outputBufferId)       mOutputFormat = format; // option B     }       @Override     void onError(…) {       …     }   });   codec.configure(format, …);   mOutputFormat = codec.getOutputFormat(); // option B   codec.start();   // wait for processing to complete   codec.stop();   codec.release();

 MediaCodec codec = MediaCodec.createByCodecName(name);   codec.configure(format, …);   MediaFormat outputFormat = codec.getOutputFormat(); // option B   codec.start();   for (;;) {     int inputBufferId = codec.dequeueInputBuffer(timeoutUs);     if (inputBufferId >= 0) {       ByteBuffer inputBuffer = codec.getInputBuffer(…);       // fill inputBuffer with valid data       …       codec.queueInputBuffer(inputBufferId, …);     }     int outputBufferId = codec.dequeueOutputBuffer(…);     if (outputBufferId >= 0) {       ByteBuffer outputBuffer = codec.getOutputBuffer(outputBufferId);       MediaFormat bufferFormat = codec.getOutputFormat(outputBufferId); // option A       // bufferFormat is identical to outputFormat       // outputBuffer is ready to be processed or rendered.       …       codec.releaseOutputBuffer(outputBufferId, …);     } else if (outputBufferId == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {       // Subsequent data will conform to new format.       // Can ignore if using getOutputFormat(outputBufferId)       outputFormat = codec.getOutputFormat(); // option B     }   }   codec.stop();   codec.release();

 MediaCodec codec = MediaCodec.createByCodecName(name);   codec.configure(format, …);   codec.start();   ByteBuffer[] inputBuffers = codec.getInputBuffers();   ByteBuffer[] outputBuffers = codec.getOutputBuffers();   for (;;) {     int inputBufferId = codec.dequeueInputBuffer(…);     if (inputBufferId >= 0) {       // fill inputBuffers[inputBufferId] with valid data       …       codec.queueInputBuffer(inputBufferId, …);     }     int outputBufferId = codec.dequeueOutputBuffer(…);     if (outputBufferId >= 0) {       // outputBuffers[outputBufferId] is ready to be processed or rendered.       …       codec.releaseOutputBuffer(outputBufferId, …);     } else if (outputBufferId == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {       outputBuffers = codec.getOutputBuffers();     } else if (outputBufferId == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {       // Subsequent data will conform to new format.       MediaFormat format = codec.getOutputFormat();     }   }   codec.stop();   codec.release();

2016-01-17 23：06编辑...

来自： http://www.cnblogs.com/raomengyang/p/5138023.html