在AVCaptureVideoDataOutputSampleBufferDelegate协议方法中:
- (void)captureOutput:(AVCaptureOutput *)captureOutput
         didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
         fromConnection:(AVCaptureConnection *)connection {
CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(pixelBuffer, 0);
 
// access the data
int width = CVPixelBufferGetWidth(pixelBuffer);
int height = CVPixelBufferGetHeight(pixelBuffer);
unsigned char *rawPixelBase = (unsigned char *)CVPixelBufferGetBaseAddress(pixelBuffer);
 
// Do something with the raw pixels here
 
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
 
AVFrame *pFrame;
pFrame = avcodec_alloc_frame();
 
avpicture_fill((AVPicture*)pFrame, rawPixelBase, PIX_FMT_RGB32, width, height);
}
其中 AVFrame和 avcodec_alloc_frame和 avpicture_fill为ffmpeg中的函数.所以需要在把它的头文件加入你的源文件中.