ios - 从前置摄像头到 UIImage 的 CMSampleBuffer

Question

我正在尝试从 CMSampleBuffer 创建 UIImage。以下代码适用于来自后置摄像头的样本缓冲区，但不适用于前置摄像头。使用前置摄像头时，CGContext初始化失败，即CGContext构造函数返回nil。我怀疑我需要使用正确的位图信息，但是有很多组合。

func convert(buffer: CMSampleBuffer) -> UIImage? {

   guard let imageBuffer = CMSampleBufferGetImageBuffer(buffer) else { return nil }

   CVPixelBufferLockBaseAddress(imageBuffer, CVPixelBufferLockFlags.readOnly)



   let baseAddress = CVPixelBufferGetBaseAddress(imageBuffer)

   let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer)

   let width = CVPixelBufferGetWidth(imageBuffer)

   let height = CVPixelBufferGetHeight(imageBuffer)



   let colorSpace = CGColorSpaceCreateDeviceRGB()

   var bitmapInfo: UInt32 = CGBitmapInfo.byteOrder32Little.rawValue

   bitmapInfo |= CGImageAlphaInfo.premultipliedFirst.rawValue & CGBitmapInfo.alphaInfoMask.rawValue

   let context = CGContext(data: baseAddress, width: width, height: height, bitsPerComponent: 8, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo)



   guard let quartzImage = context?.makeImage() else { return nil }

   CVPixelBufferUnlockBaseAddress(imageBuffer, CVPixelBufferLockFlags.readOnly)

   let image = UIImage(cgImage: quartzImage)



   return image

}

它伴随着以下错误：“CGBitmapContextCreate：无效数据字节/行：对于 8 个整数位/分量、3 个分量、kCGImageAlphaPremultipliedFirst，应至少为 2560。”