pragma mark buffer转image

• (UIImage *)convertSampleBufferToUIImageSampleBuffer:(CMSampleBufferRef)sampleBuffer{

  // Get a CMSampleBuffer's Core Video image buffer for the media data
  CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
  // Lock the base address of the pixel buffer
  CVPixelBufferLockBaseAddress(imageBuffer, 0);

  // Get the number of bytes per row for the plane pixel buffer
  void *baseAddress = CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0);

  // Get the number of bytes per row for the plane pixel buffer
  size_t bytesPerRow = CVPixelBufferGetBytesPerRowOfPlane(imageBuffer,0);
  // Get the pixel buffer width and height
  size_t width = CVPixelBufferGetWidth(imageBuffer);
  size_t height = CVPixelBufferGetHeight(imageBuffer);

  // Create a device-dependent gray color space
  CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();

  // Create a bitmap graphics context with the sample buffer data
  CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8,
  bytesPerRow, colorSpace, kCGImageAlphaNone);
  // Create a Quartz image from the pixel data in the bitmap graphics context
  CGImageRef quartzImage = CGBitmapContextCreateImage(context);
  // Unlock the pixel buffer
  CVPixelBufferUnlockBaseAddress(imageBuffer,0);

  // Free up the context and color space
  CGContextRelease(context);
  CGColorSpaceRelease(colorSpace);

  // Create an image object from the Quartz image
  // UIImage *image = [UIImage imageWithCGImage:quartzImage];
  UIImage *image = [UIImage imageWithCGImage:quartzImage scale:1.0 orientation:UIImageOrientationRight];

  // Release the Quartz image
  CGImageRelease(quartzImage);

  return (image);
  }

• (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer {

  // 为媒体数据设置一个CMSampleBuffer的Core Video图像缓存对象
  CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
  // 锁定pixel buffer的基地址
  CVPixelBufferLockBaseAddress(imageBuffer, 0);

  // 得到pixel buffer的基地址
  void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer);

  // 得到pixel buffer的行字节数
  size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
  // 得到pixel buffer的宽和高
  size_t width = CVPixelBufferGetWidth(imageBuffer);
  size_t height = CVPixelBufferGetHeight(imageBuffer);

  // 创建一个依赖于设备的RGB颜色空间
  CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

  // 用抽样缓存的数据创建一个位图格式的图形上下文（graphics context）对象
  CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8,
  bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
  // 根据这个位图context中的像素数据创建一个Quartz image对象
  CGImageRef quartzImage = CGBitmapContextCreateImage(context);
  // 解锁pixel buffer
  CVPixelBufferUnlockBaseAddress(imageBuffer,0);

  // 释放context和颜色空间
  CGContextRelease(context);
  CGColorSpaceRelease(colorSpace);

  // 用Quartz image创建一个UIImage对象image
  // UIImage *image = [UIImage imageWithCGImage:quartzImage];

UIImage *image = nil;
if (_input.device.position == AVCaptureDevicePositionFront) {
    image = [UIImage imageWithCGImage:quartzImage scale:1.0 orientation:UIImageOrientationLeftMirrored];

}else{
    image = [UIImage imageWithCGImage:quartzImage scale:1.0 orientation:UIImageOrientationRight];
}

//UIImageOrientationRight
// 释放Quartz image对象
CGImageRelease(quartzImage);

return (image);

}