iOS: convert UIImage to CMSampleBuffer

Question

Some questions address how to convert a CMSampleBuffer to a UIImage, but there are no answers on how to do the reverse, ie, convert UIImage to CMSampleBuffer.

func convertImageToBuffer(from image: UIImage) -> CVPixelBuffer? {
    let attrs = [
        String(kCVPixelBufferCGImageCompatibilityKey) : kCFBooleanTrue,
        String(kCVPixelBufferCGBitmapContextCompatibilityKey) : kCFBooleanTrue
        ] as [String : Any]
    var buffer : CVPixelBuffer?
    let status = CVPixelBufferCreate(kCFAllocatorDefault, Int(image.size.width), Int(image.size.height), kCVPixelFormatType_32ARGB, attrs as CFDictionary, &buffer)
    guard (status == kCVReturnSuccess) else {
        return nil
    }

    CVPixelBufferLockBaseAddress(buffer!, CVPixelBufferLockFlags(rawValue: 0))
    let pixelData = CVPixelBufferGetBaseAddress(buffer!)

    let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
    let context = CGContext(data: pixelData, width: Int(image.size.width), height: Int(image.size.height), bitsPerComponent: 8, bytesPerRow: CVPixelBufferGetBytesPerRow(buffer!), space: rgbColorSpace, bitmapInfo: CGImageAlphaInfo.noneSkipFirst.rawValue)

    context?.translateBy(x: 0, y: image.size.height)
    context?.scaleBy(x: 1.0, y: -1.0)

    UIGraphicsPushContext(context!)
    image.draw(in: CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))
    UIGraphicsPopContext()
    CVPixelBufferUnlockBaseAddress(buffer!, CVPixelBufferLockFlags(rawValue: 0))

    return buffer
}

Answer 1

You are halfway done. Just convert CVPixelBuffer to CMSampleBuffer:

extension UIImage {
    
    var cvPixelBuffer: CVPixelBuffer? {
        let attrs = [
            String(kCVPixelBufferCGImageCompatibilityKey): kCFBooleanTrue,
            String(kCVPixelBufferCGBitmapContextCompatibilityKey): kCFBooleanTrue
            ] as [String: Any]
        var buffer: CVPixelBuffer?
        let status = CVPixelBufferCreate(kCFAllocatorDefault, Int(self.size.width), Int(self.size.height), kCVPixelFormatType_32ARGB, attrs as CFDictionary, &buffer)
        guard status == kCVReturnSuccess else {
            return nil
        }

        CVPixelBufferLockBaseAddress(buffer!, CVPixelBufferLockFlags(rawValue: 0))
        let pixelData = CVPixelBufferGetBaseAddress(buffer!)

        let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
        let context = CGContext(data: pixelData, width: Int(self.size.width), height: Int(self.size.height), bitsPerComponent: 8, bytesPerRow: CVPixelBufferGetBytesPerRow(buffer!), space: rgbColorSpace, bitmapInfo: CGImageAlphaInfo.noneSkipFirst.rawValue)

        context?.translateBy(x: 0, y: self.size.height)
        context?.scaleBy(x: 1.0, y: -1.0)

        UIGraphicsPushContext(context!)
        self.draw(in: CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height))
        UIGraphicsPopContext()
        CVPixelBufferUnlockBaseAddress(buffer!, CVPixelBufferLockFlags(rawValue: 0))

        return buffer
    }
       
    func createCMSampleBuffer() -> CMSampleBuffer? {
        let pixelBuffer = cvPixelBuffer
        var newSampleBuffer: CMSampleBuffer?
        var timimgInfo: CMSampleTimingInfo?
        var videoInfo: CMVideoFormatDescription?
        CMVideoFormatDescriptionCreateForImageBuffer(allocator: nil, imageBuffer: pixelBuffer!, formatDescriptionOut: &videoInfo)
        CMSampleBufferCreateForImageBuffer(allocator: kCFAllocatorDefault,
                                           imageBuffer: pixelBuffer!,
                                           dataReady: true,
                                           makeDataReadyCallback: nil,
                                           refcon: nil,
                                           formatDescription: videoInfo!,
                                           sampleTiming: &timimgInfo,
                                           sampleBufferOut: &newSampleBuffer)
        return newSampleBuffer!
    }
    
}