ios – 用增强现实录制视频的最佳方式是什么?

使用增强现实录制视频的最佳方式是什么? (从iPhone / iPad相机中添加文字,图像徽标到相框)

以前我试图弄清楚如何绘制到CIImage(How to draw text into CIImage?)并将CIImage转换回CMSampleBuffer(CIImage back to CMSampleBuffer)

我几乎做了所有事情,只是在AVAssetWriterInput中使用新的CMSampleBuffer录制视频时遇到问题

但是这个解决方案总体上并不好,它在将CIImage转换为CVPixelBuffer时会占用大量CPU(ciContext.render(ciImage!,to:aBuffer))

所以我想在这里停下来找一些其他的方法来录制带有增强现实的视频(例如,在将视频编码为mp4文件的同时在帧内动态添加(绘制)文本)

在这里,我尝试过,不想再使用了……

// convert original CMSampleBuffer to CIImage, 
// combine multiple `CIImage`s into one (adding augmented reality -  
// text or some additional images)
let pixelBuffer: CVPixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)!
let ciimage : CIImage = CIImage(cvPixelBuffer: pixelBuffer)
var outputImage: CIImage?
let images : Array<CIImage> = [ciimage, ciimageSec!] // add all your CIImages that you'd like to combine
for image in images {
    outputImage = outputImage == nil ? image : image.composited(over: outputImage!)
}

// allocate this class variable once         
if pixelBufferNew == nil {
    CVPixelBufferCreate(kCFAllocatorSystemDefault, CVPixelBufferGetWidth(pixelBuffer),  CVPixelBufferGetHeight(pixelBuffer), kCVPixelFormatType_32BGRA, nil, &pixelBufferNew)
}

// convert CIImage to CVPixelBuffer
let ciContext = CIContext(options: nil)
if let aBuffer = pixelBufferNew {
    ciContext.render(outputImage!, to: aBuffer) // >>> IT EATS A LOT OF <<< CPU
}

// convert new CVPixelBuffer to new CMSampleBuffer
var sampleTime = CMSampleTimingInfo()
sampleTime.duration = CMSampleBufferGetDuration(sampleBuffer)
sampleTime.presentationTimeStamp = CMSampleBufferGetPresentationTimeStamp(sampleBuffer)
sampleTime.decodeTimeStamp = CMSampleBufferGetDecodeTimeStamp(sampleBuffer)
var videoInfo: CMVideoFormatDescription? = nil
CMVideoFormatDescriptionCreateForImageBuffer(kCFAllocatorDefault, pixelBufferNew!, &videoInfo)
var oBuf: CMSampleBuffer?
CMSampleBufferCreateForImageBuffer(kCFAllocatorDefault, pixelBufferNew!, true, nil, nil, videoInfo!, &sampleTime, &oBuf)

/*
try to append new CMSampleBuffer into a file (.mp4) using 
AVAssetWriter & AVAssetWriterInput... (I met errors with it, original buffer works ok 
- "from func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection)")
*/*

有没有更好的解决方案?

现在我回答我自己的问题

最好的方法是使用Objective-C类(.mm)我们可以使用OpenCV并从CMSampleBuffer轻松/快速转换为cv :: Mat并在处理后返回CMSampleBuffer

我们可以轻松地从Swift调用Objective-C函数

https://stackoverflow.com/questions/49066195/what-is-the-best-way-to-record-a-video-with-augmented-reality

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