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public class VideoActivity extends Activity implements SurfaceHolder.Callback,Camera.PreviewCallback {static int screenWidth = 0;
static int screenHeight = 0;
private SurfaceView mSurfaceview = null;
private SurfaceHolder mSurfaceHolder = null;
private Camera mCamera = null;
private byte yuv_frame[];
private Parameters mParameters;
static int mwidth = 320;
static int mheight = 240;// Setup
protected void onCreate(Bundle savedInstanceState) {requestWindowFeature(Window.FEATURE_NO_TITLE);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_video_capture);
mSurfaceview = (SurfaceView) findViewById(R.id.surfaceview);
mSurfaceHolder = mSurfaceview.getHolder();
mSurfaceHolder.addCallback(this);
screenWidth = getWindowManager().getDefaultDisplay().getWidth();
screenHeight = getWindowManager().getDefaultDisplay().getHeight();
LayoutParams layoutparam = new LayoutParams(screenWidth, screenHeight);
SurfaceHolder holder = mSurface.getHolder();
holder.setFixedSize(screenWidth,screenHeight);
}void startcapture()
{try {if (mCamera == null) {mCamera = Camera.open();
}
mCamera.stopPreview();
mParameters = mCamera.getParameters();
mParameters.setPreviewSize(mwidth, mheight);//set video resolution ratio
mParameters.setPreviewFrameRate(15); //set frame rate
mCamera.setParameters(mParameters);
int mformat = mParameters.getPreviewFormat();
int bitsperpixel = ImageFormat.getBitsPerPixel(mformat);
yuv_frame = new byte[mwidth * mheight * bitsperpixel / 8];//buffer to store NV21preview  data
mCamera.addCallbackBuffer(yuv_frame);
mCamera.setPreviewDisplay(mSurfaceHolder);
mCamera.setPreviewCallbackWithBuffer(this);//set callback for camera
mCamera.startPreview();//trigger callback onPreviewFrame
}catch (IOException e) {e.printStackTrace();
}
}@Override
public void onPreviewFrame(byte[] data, Camera camera) {//add code to process the data captured,data layout is YYYYYYYYVUVU,should be converted to                               // YYYYYYYYUUVV before encoded
camera.addCallbackBuffer(yuv_frame);
}
protected void onPause() {super.onPause();
}
public void onResume() {super.onResume();
}
protected void onDestroy() {if (mCamera != null) {mCamera.setPreviewCallback(null);
mCamera.stopPreview(); //stop capture video data
mCamera.release();
mCamera = null;
}
super.onDestroy();
}
@Override
public void surfaceCreated(SurfaceHolder holder) {}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width_size,int height_size) {startcapture();//start capture NV21 video data
}
}

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int frame_rate = 15;
int mWidth = 640;
int mHeight 480;
AVCaptureDeviceInput *videoInput = nil;
AVCaptureVideoDataOutput *avCaptureVideoDataOutput =nil;
AVCaptureSession* mCaptureSession = nil;
AVCaptureDevice *mCaptureDevice = nil;- (void)startCapture
{if(mCaptureDevice || mCaptureSession)
{NSLog(@"Already capturing");
return;
}
NSArray *cameras = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
for (AVCaptureDevice *device in cameras){if (device.position == AVCaptureDevicePositionFront){AVCaptureDevice = device;
}
}
if(AVCaptureDevice == nil)
{AVCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
}
if(mCaptureDevice == nil)
{NSLog(@"Failed to get valide capture device");
return;
}
NSError *error = nil;
videoInput = [AVCaptureDeviceInput deviceInputWithDevice:mCaptureDevice error:&error];
if (!videoInput)
{NSLog(@"Failed to get video input");
mCaptureDevice = nil;
return;
}
mCaptureSession = [[AVCaptureSession alloc] init];
mCaptureSession.sessionPreset = AVCaptureSessionPreset640x480;//set video resolution ratio
[mCaptureSession addInput:videoInput];
avCaptureVideoDataOutput = [[AVCaptureVideoDataOutput alloc] init];
NSDictionary *settings = [[NSDictionary alloc] initWithObjectsAndKeys:
[NSNumber numberWithUnsignedInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange],                                   kCVPixelBufferPixelFormatTypeKey,
[NSNumber numberWithInt: mWidth], (id)kCVPixelBufferWidthKey,
[NSNumber numberWithInt: mHeight], (id)kCVPixelBufferHeightKey,
nil];
avCaptureVideoDataOutput.videoSettings = settings;
[settings release];
avCaptureVideoDataOutput.minFrameDuration = CMTimeMake(1, frame_rate);//set video frame rate
avCaptureVideoDataOutput.alwaysDiscardsLateVideoFrames = YES;
dispatch_queue_t queue_ = dispatch_queue_create("www.easemob.com", NULL);
[avCaptureVideoDataOutput setSampleBufferDelegate:self queue:queue_];
[mCaptureSession addOutput:avCaptureVideoDataOutput];
[avCaptureVideoDataOutput release];
dispatch_release(queue_);
}
- (void)stopCapture
{if(mCaptureSession){[mCaptureSession stopRunning];
[mCaptureSession removeInput:videoInput];
[mCaptureSession removeOutput:avCaptureVideoDataOutput];
[avCaptureVideoDataOutput release];
[videoInput release];
[mCaptureSession release], mCaptureSession = nil;
[mCaptureDevice release], mCaptureDevice = nil;
}
}
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
/* unlock the buffer*/
if(CVPixelBufferLockBaseAddress(imageBuffer, 0) == kCVReturnSuccess)
{UInt8 *bufferbasePtr = (UInt8 *)CVPixelBufferGetBaseAddress(imageBuffer);
UInt8 *bufferPtr = (UInt8 *)CVPixelBufferGetBaseAddressOfPlane(imageBuffer,0);
UInt8 *bufferPtr1 = (UInt8 *)CVPixelBufferGetBaseAddressOfPlane(imageBuffer,1);
size_t buffeSize = CVPixelBufferGetDataSize(imageBuffer);
size_t width = CVPixelBufferGetWidth(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
size_t bytesrow0 = CVPixelBufferGetBytesPerRowOfPlane(imageBuffer,0);
size_t bytesrow1  = CVPixelBufferGetBytesPerRowOfPlane(imageBuffer,1);
size_t bytesrow2 = CVPixelBufferGetBytesPerRowOfPlane(imageBuffer,2);
UInt8 *yuv420_data = (UInt8 *)malloc(width * height *3/ 2);//buffer to store YUV with layout YYYYYYYYUUVV/* convert NV21 data to YUV420*/UInt8 *pY = bufferPtr ;
UInt8 *pUV = bufferPtr1;
UInt8 *pU = yuv420_data + width*height;
UInt8 *pV = pU + width*height/4;
for(int i =0;i<height;i++)
{memcpy(yuv420_data+i*width,pY+i*bytesrow0,width);
}
for(int j = 0;j<height/2;j++)
{for(int i =0;i<width/2;i++)
{*(pU++) = pUV[i<<1];
*(pV++) = pUV[(i<<1) + 1];
}
pUV+=bytesrow1;
}
//add code to push yuv420_data to video encoder herefree(yuv420_data);
/* unlock the buffer*/
CVPixelBufferUnlockBaseAddress(imageBuffer, 0);
}