CIImage返回到CMSampleBuffer

Question

我记录视频(.mp4文件)使用AVAssetWriter与CMSampleBuffer数据(从视频，音频输入)。

当我想要处理帧时，我将CMSampleBuffer转换为CIImage并对其进行处理。

但是如何使用我从CIImage新处理的图像缓冲区更新CMSampleBuffer

func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
    if output == videoOutput {
       let imageBuffer: CVPixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)!
       let ciimage: CIImage = CIImage(cvPixelBuffer: imageBuffer)
       ... // my code to process CIImage (for example add augmented reality)
       // but how to convert it back to CMSampleBuffer?
       // because AVAssetWriterInput to encode video/audio in file needs CMSampleBuffer
       ...
    } 
    ...
}

Answer 1

您需要使用CIContext的render(_:to:bounds:colorSpace:)方法将CIImage呈现为CVPixelBuffer。

然后，您可以使用例如CMSampleBufferCreateReadyWithImageBuffer(_:_:_:_:_:)从CVPixelBuffer创建CMSampleBuffer

出于效率的原因，您可能需要使用CVPixelBuffer池，苹果的AVCamPhotoFilter示例代码中显示了一个这样的示例。具体来说，请参阅RosyCIRenderer class。

另请参阅此答案，它可能对您的Applying a CIFilter to a Video File and Saving it有所帮助