convert CMSampleBufferRef to UIImage

Question

I\'m captuting video with AVCaptureSession. But I would like to convert the captured image to an UIImage.

I found some code on Internet:

- (UIImage *         


        

Answer 1

You can try this code.

-(UIImage *) screenshotOfVideoStream:(CMSampleBufferRef)samImageBuff
  {
       CVImageBufferRef imageBuffer =  
         CMSampleBufferGetImageBuffer(samImageBuff);
       CIImage *ciImage = [CIImage imageWithCVPixelBuffer:imageBuffer];
       CIContext *temporaryContext = [CIContext contextWithOptions:nil];
       CGImageRef videoImage = [temporaryContext
                         createCGImage:ciImage
                         fromRect:CGRectMake(0, 0,
                         CVPixelBufferGetWidth(imageBuffer),
                         CVPixelBufferGetHeight(imageBuffer))];

       UIImage *image = [[UIImage alloc] initWithCGImage:videoImage];
       CGImageRelease(videoImage);
      return image;
}

It work for me.

Answer 2

Your best bet will be to set the capture video data output's videoSettings to a dictionary that specifies the pixel format you want, which you'll need to set to some variation on RGB that CGBitmapContext can handle.

The documentation has a list of all of the pixel formats that Core Video can process. Only a tiny subset of those are supported by CGBitmapContext. The format that the code you found on the internet is expecting is kCVPixelFormatType_32BGRA, but that might have been written for Macs—on iOS devices, kCVPixelFormatType_32ARGB (big-endian) might be faster. Try them both, on the device, and compare frame rates.