Here's a function (code from Apple documentation) that converts a CMSampleBuffer into a UIImage
func imageFromSampleBuffer(sampleBuffer: CMSampleBuffer) -> UIImage {
// Get a CMSampleBuffer's Core Video image buffer for the media data
var imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)
// Lock the base address of the pixel buffer
CVPixelBufferLockBaseAddress(imageBuffer, 0)
// Get the number of bytes per row for the pixel buffer
var baseAddress = CVPixelBufferGetBaseAddress(imageBuffer)
// Get the number of bytes per row for the pixel buffer
var bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer)
// Get the pixel buffer width and height
var width = CVPixelBufferGetWidth(imageBuffer)
var height = CVPixelBufferGetHeight(imageBuffer)
// Create a device-dependent RGB color space
var colorSpace = CGColorSpaceCreateDeviceRGB()
// Create a bitmap graphics context with the sample buffer data
let bitmapInfo = CGBitmapInfo(CGImageAlphaInfo.NoneSkipLast.rawValue)
var context = CGBitmapContextCreate(baseAddress, width, height, 8, bytesPerRow, colorSpace, bitmapInfo)
// Create a Quartz image from the pixel data in the bitmap graphics context
var quartzImage = CGBitmapContextCreateImage(context);
// Unlock the pixel buffer
CVPixelBufferUnlockBaseAddress(imageBuffer,0);
// Create an image object from the Quartz image
var image = UIImage(CGImage: quartzImage)!
return image
}
When I try to visualize the UIImage using a UIImageView, I get nothing.
Any Ideas?
This is a solution for Swift 3.0, where CMSampleBuffer
is extended, creating a variable that gives you an optional UIImage
.
import AVFoundation
extension CMSampleBuffer {
var uiImage: UIImage? {
guard let imageBuffer = CMSampleBufferGetImageBuffer(self) else { return nil }
CVPixelBufferLockBaseAddress(imageBuffer, CVPixelBufferLockFlags(rawValue: 0))
let baseAddress = CVPixelBufferGetBaseAddress(imageBuffer)
let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer)
let width = CVPixelBufferGetWidth(imageBuffer)
let height = CVPixelBufferGetHeight(imageBuffer)
let colorSpace = CGColorSpaceCreateDeviceRGB()
let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.noneSkipFirst.rawValue | CGBitmapInfo.byteOrder32Little.rawValue)
guard let context = CGContext(data: baseAddress,
width: width,
height: height,
bitsPerComponent: 8,
bytesPerRow: bytesPerRow,
space: colorSpace,
bitmapInfo: bitmapInfo.rawValue) else { return nil }
guard let cgImage = context.makeImage() else { return nil }
CVPixelBufferUnlockBaseAddress(imageBuffer,CVPixelBufferLockFlags(rawValue: 0));
return UIImage(cgImage: cgImage)
}
}