这里简单说下IOS摄像头采集YUV420数据。
步骤:
1.初始采集数据需要的对象
2.设置采集回调的代理并开始
3.在回调中获取到采集的数据(注意:这里采集到的数据格式NV12并不是YUV420格式数据)
4.将NV12转成我们需要的YUV420
代码如下:
//摄像头采集
capturSession=[[AVCaptureSessionalloc]init];
capturSession.sessionPreset=AVCaptureSessionPreset1920x1080;//设置采集的分辨率
captureDevice=[AVCaptureDevicedefaultDeviceWithMediaType:AVMediaTypeVideo];
NSError *error=nil;
captureDeviceInput=[AVCaptureDeviceInputdeviceInputWithDevice:captureDeviceerror:&error];
if (captureDeviceInput) {
[capturSessionaddInput:captureDeviceInput];
}else{
NSLog(@"%@",error);
}
//初始化流输出对象
captureVideoDataOutput=[[AVCaptureVideoDataOutputalloc]init];
[captureVideoDataOutputsetAlwaysDiscardsLateVideoFrames:YES];
//设置输出参数
NSDictionary *settingsDic = [[NSDictionaryalloc] initWithObjectsAndKeys:
[NSNumbernumberWithUnsignedInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange],
kCVPixelBufferPixelFormatTypeKey,
nil];// X264_CSP_NV12
captureVideoDataOutput.videoSettings = settingsDic;
dispatch_queue_t queue =dispatch_queue_create("myQueue",NULL);
[captureVideoDataOutputsetSampleBufferDelegate:selfqueue:queue];
[capturSessionaddOutput:captureVideoDataOutput];
/* ---------------------------------------------------------------------- */
previewLayer = [[AVCaptureVideoPreviewLayeralloc] initWithSession:capturSession];
//设置显示的视图位置
previewLayer.frame =CGRectMake(50,330, 160,200);
[self.view.layeraddSublayer:previewLayer];
//开始采集
[capturSessionstartRunning];
//回调函数
#pragma mark -- AVCaptureVideo(Audio)DataOutputSampleBufferDelegate method
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
if (captureOutput == captureVideoDataOutput) {
CVImageBufferRef imageBuffer =CMSampleBufferGetImageBuffer(sampleBuffer);
// 获取采集的数据
CVPixelBufferLockBaseAddress(imageBuffer,0);
CMTime pts =CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
CMTime duration =CMSampleBufferGetDuration(sampleBuffer);
void *imageAddress = CVPixelBufferGetBaseAddressOfPlane(imageBuffer,0);//YYYYYYYY
size_t row0=CVPixelBufferGetBytesPerRowOfPlane(imageBuffer,0);
void *imageAddress1=CVPixelBufferGetBaseAddressOfPlane(imageBuffer,1);//UVUVUVUV
size_t row1=CVPixelBufferGetBytesPerRowOfPlane(imageBuffer,1);
size_t width =CVPixelBufferGetWidth(imageBuffer);
size_t height =CVPixelBufferGetHeight(imageBuffer);
CVPixelBufferUnlockBaseAddress(imageBuffer,0);
size_t a=width*height;
//开始将NV12转换成YUV420
uint8_t *yuv420Data=(uint8_t*)malloc(a*1.5);
for (int i=0; i<height; ++i) {
memcpy(yuv420Data+i*width, imageAddress+i*row0, width);
}
uint8_t *UV=imageAddress1;
uint8_t *U=yuv420Data+a;
uint8_t *V=U+a/4;
for (int i=0; i<0.5*height; i++) {
for (int j=0; j<0.5*width; j++) {
// printf("%d\n",j<<1);
*(U++)=UV[j<<1];
*(V++)=UV[(j<<1)+1];
}
UV+=row1;
}
//这里根据自己的情况对YUV420数据进行处理
//...........
//最后记得释放哦
free(yuv420Data);
}
}
