Creates a SMSampleBuffer for video to be used in unit tests

CreateEmptyVideo.swift

func createEmptyVideo() -> CMSampleBuffer {
    var pixelBuffer : CVPixelBuffer? = nil
    CVPixelBufferCreate(kCFAllocatorDefault, 100, 100, kCVPixelFormatType_444YpCbCr10BiPlanarVideoRange, nil, &pixelBuffer)
    
    var info = CMSampleTimingInfo()
    info.presentationTimeStamp = .zero
    info.duration = .invalid
    info.decodeTimeStamp = .invalid
    
    
    var formatDesc: CMFormatDescription? = nil
    CMVideoFormatDescriptionCreateForImageBuffer(allocator: kCFAllocatorDefault, imageBuffer: pixelBuffer!, formatDescriptionOut: &formatDesc)
    
    var sampleBuffer: CMSampleBuffer? = nil
    
    CMSampleBufferCreateReadyWithImageBuffer(
        allocator: kCFAllocatorDefault,
        imageBuffer: pixelBuffer!,
        formatDescription: formatDesc!,
        sampleTiming: &info,
        sampleBufferOut: &sampleBuffer
    )
    
    return sampleBuffer!
}