What is the best way to record video with augmented reality
What's the best way to record augmented reality videos? (add text, image logos to frames from iPhone / iPad)
I used to try to figure out how to drawCIImage
( How do I draw text in CIImage? ) And convert
CIImage
back to
CMSampleBuffer
( CIImage back to CMSampleBuffer )
I did almost everything, only the problem with recording video using new CMSampleBuffer
inAVAssetWriterInput
But this solution is not very good anyway, it eats a lot of CPU when converting CIImage
to CVPixelBuffer
( ciContext.render(ciImage!, to: aBuffer)
)
So, I want to stop here and find other ways to record video with augmented reality (for example, dynamically add (draw) text inside frames when encoding video to mp4 file)
Here's what I tried and don't want to use anymore ...
// 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)")
*/*
Is there a better solution?
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