My app recognises an event using Vision and uses CMSampleBuffer to do so.
After the event I am recording the video already using AVWriter successfully.
Now I want to record the full motion and thus record 1-2 seconds before the event occurred.
I tried pushing the CMSampleBuffer into a ring buffer, but that starves the camera of buffers.
func captureOutput(_ output: AVCaptureOutput,
didOutput sampleBuffer: CMSampleBuffer,
from connection: AVCaptureConnection) {
// sends that to detectBall
/// Gets called by the camera every time there is a new buffer available
func detectBall(inBuffer buffer: CMSampleBuffer,
ballDetectionRequest: VNCoreMLRequest,
orientation: CGImagePropertyOrientation,
frame: NormalizedPoint,
updatingRingBuffer: PassthroughSubject<AppEnvironment.AVState.RingBufferItem, Never>
) throws {
// I tried to convert it into a CVPixelBuffer but its a shallow copy as well so it also starves the camera
let imageBuffer: CVPixelBuffer = CMSampleBufferGetImageBuffer(buffer)!
/// rotated 90 because of the cameras native landscape orientation
let visionHandler = VNImageRequestHandler(ciImage: croppedImage, options: [:])
try visionHandler.perform([ballDetectionRequest])
if let results = ballDetectionRequest as? [VNClassificationObservation] {
// Filter out classification results with low confidence
let filteredResults = results.filter { $0.confidence > 0.9 }
guard let topResult = results.first,
topResult.confidence > 0.9 else { return }
// print(" its a: \(topResult.identifier)")
// print("copy buffer")
updatingRingBuffer.send(AppEnvironment.AVState.RingBufferItem(
/// HERE IS THE PROBLEM: AS SOON AS I SEND IT SOMEWHERE ELSE THE CAMERA IS STARVED
buffer: imageBuffer,
ball: topResult.identifier == "ball")
How can I achieve to store these 1-2 seconds of video continuously without writing it to disk and then prepending it to the video file?
Thanks!
I am working with the Vision framework in iOS 13 and am trying to achieve the following tasks;
Take an image (in this case, a CIImage) and locate all faces in the image using Vision.
Crop each face into its own CIImage (I'll call this a "face image").
Filter each face image using a CoreImage filter, such as a blur or comic book effect.
Composite the face image back over the original image, hereby creating effects that only apply to the face.
A better example of this would be the end goal of taking a live camera feed from an AVCaptureSession and blurring every face in the video frame, compositing the blurred faces back over the original image for saving.
I almost have this working, save for the fact that there seems to be a coordinates/translation issue. For example, when I test this code and move my face, the "blurred" section goes the wrong direction (if I turn my face right, the box goes left, if I look up, the box goes down). While I think this may have something to do with mirroring on the front-facing camera, I can't seem to figure out what I should try next;
func drawFaceBox(bufferImage: CIImage, observations: [VNFaceObservation]) -> CVPixelBuffer? {
// The filter
let blur = CIFilter(name: "CICrystallize")
// The unfiltered image, prepared for filtering
var filteredImage = bufferImage
// Find and crop each face
if !observations.isEmpty {
for face in observations {
let faceRect = VNImageRectForNormalizedRect(face.boundingBox, Int(bufferImage.extent.size.width), Int(bufferImage.extent.size.height))
let croppedFace = bufferImage.cropped(to: faceRect)
blur?.setValue(croppedFace, forKey: kCIInputImageKey)
blur?.setValue(10.0, forKey: kCIInputRadiusKey)
if let blurred = blur?.value(forKey: kCIOutputImageKey) as? CIImage {
compositorCIFilter?.setValue(blurred, forKey: kCIInputImageKey)
compositorCIFilter?.setValue(filteredImage, forKey: kCIInputBackgroundImageKey)
if let output = compositorCIFilter?.value(forKey: kCIOutputImageKey) as? CIImage {
filteredImage = output
}
}
}
}
// Convert image to CVPixelBuffer and return. This part works fine.
}
Any thoughts on how I can composite the blurred face image(s) back to their original position with accuracy? Or any other approach to only filter part of the original CIImage to avoid this issue altogether/save processing? Thanks!
I believe this issue stems from an orientation problem earlier on in the pipeline (specifically, during the output of the sample buffers from the camera, which is where the Vision task was instantiated). I have updated my didOutputSampleBuffer code like so;
func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
...
// Setup the current device orientation
let curDeviceOrientation = UIDevice.current.orientation
// Handle the image property orientation
//let orientation = self.exifOrientation(from: curDeviceOrientation)
// Setup the image request handler
//let handler = VNImageRequestHandler(cvPixelBuffer: pixelBuffer, orientation: CGImagePropertyOrientation(rawValue: UInt32(1))!)
let handler = VNImageRequestHandler(cvPixelBuffer: pixelBuffer, options: [:])
// Setup the completion handler
let completion: VNRequestCompletionHandler = {request, error in
let observations = request.results as! [VNFaceObservation]
// Draw faces
DispatchQueue.main.async {
// HANDLE FACES
self.drawFaceBoxes(for: observations)
}
}
// Setup the image request
let request = VNDetectFaceRectanglesRequest(completionHandler: completion)
// Handle the request
do {
try handler.perform([request])
} catch {
print(error)
}
}
As noted, I have commented out the let orientation = ... and the first let handler = ..., which was using the orientation. By removing the reference to the orientation, I seem to have removed any issue with orientation in the Vision calculations.
I am working on a swift application and I want to take a picture during the video when the camera is not moving or when user focuses on something.
i used AVCaptureVideoDataOutputSampleBufferDelegate *captureOutput method which giving me image every time after starting camera. but I want to take only when the camera is not moving or focused.
func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
print("didOutput")
guard let hasImage = CMSampleBufferGetImageBuffer(sampleBuffer) else {
print("no image")
return
}
let ciimage : CIImage = CIImage(cvPixelBuffer: hasImage)
DispatchQueue.main.async {
self.liveCamImage = self.convert(cmage: ciimage)
}
}
is there any solution for this
You can try to use adjusting focus property of your capture device (AVCaptureDevice), when it is false the focus is stable. See detailed documentation below.
/**
#property adjustingFocus
#abstract
Indicates whether the receiver is currently performing a focus scan to adjust focus.
#discussion
The value of this property is a BOOL indicating whether the receiver's camera focus is being automatically adjusted by means of a focus scan, because its focus mode is AVCaptureFocusModeAutoFocus or AVCaptureFocusModeContinuousAutoFocus. Clients can observe the value of this property to determine whether the camera's focus is stable.
#seealso lensPosition
#seealso AVCaptureAutoFocusSystem
*/
open var isAdjustingFocus: Bool { get }
I am trying to record, and then save, a video in Swift using AVFoundation. This works. I am also trying to add an overlay, such as a text label containing the date, to the video.
For example: the video saved is not only what the camera sees, but the timestamp as well.
Here is how I am saving the video:
func fileOutput(_ output: AVCaptureFileOutput, didFinishRecordingTo outputFileURL: URL, from connections: [AVCaptureConnection], error: Error?) {
saveVideo(toURL: movieURL!)
}
private func saveVideo(toURL url: URL) {
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: url)
}) { (success, error) in
if(success) {
print("Video saved to Camera Roll.")
} else {
print("Video failed to save.")
}
}
}
I have a movieOuput that is an AVCaptureMovieFileOutput. My preview layer does not contain any sublayers. I tried adding the timestamp label's layer to the previewLayer, but this did not succeed.
I have tried Ray Wenderlich's example as well as this stack overflow question. Lastly, I also tried this tutorial, all of which to no avail.
How can I add an overlay to my video that is in the saved video in the camera roll?
Without more information it sounds like what you are asking for is a WATERMARK.
Not an overlay.
A watermark is a markup on the video that will be saved with the video.
An overlay is generally showed as subviews on the preview layer and will not be saved with the video.
Check this out here: https://stackoverflow.com/a/47742108/8272698
func addWatermark(inputURL: URL, outputURL: URL, handler:#escaping (_ exportSession: AVAssetExportSession?)-> Void) {
let mixComposition = AVMutableComposition()
let asset = AVAsset(url: inputURL)
let videoTrack = asset.tracks(withMediaType: AVMediaType.video)[0]
let timerange = CMTimeRangeMake(kCMTimeZero, asset.duration)
let compositionVideoTrack:AVMutableCompositionTrack = mixComposition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: CMPersistentTrackID(kCMPersistentTrackID_Invalid))!
do {
try compositionVideoTrack.insertTimeRange(timerange, of: videoTrack, at: kCMTimeZero)
compositionVideoTrack.preferredTransform = videoTrack.preferredTransform
} catch {
print(error)
}
let watermarkFilter = CIFilter(name: "CISourceOverCompositing")!
let watermarkImage = CIImage(image: UIImage(named: "waterMark")!)
let videoComposition = AVVideoComposition(asset: asset) { (filteringRequest) in
let source = filteringRequest.sourceImage.clampedToExtent()
watermarkFilter.setValue(source, forKey: "inputBackgroundImage")
let transform = CGAffineTransform(translationX: filteringRequest.sourceImage.extent.width - (watermarkImage?.extent.width)! - 2, y: 0)
watermarkFilter.setValue(watermarkImage?.transformed(by: transform), forKey: "inputImage")
filteringRequest.finish(with: watermarkFilter.outputImage!, context: nil)
}
guard let exportSession = AVAssetExportSession(asset: asset, presetName: AVAssetExportPreset640x480) else {
handler(nil)
return
}
exportSession.outputURL = outputURL
exportSession.outputFileType = AVFileType.mp4
exportSession.shouldOptimizeForNetworkUse = true
exportSession.videoComposition = videoComposition
exportSession.exportAsynchronously { () -> Void in
handler(exportSession)
}
}
And heres how to call the function.
let outputURL = NSURL.fileURL(withPath: "TempPath")
let inputURL = NSURL.fileURL(withPath: "VideoWithWatermarkPath")
addWatermark(inputURL: inputURL, outputURL: outputURL, handler: { (exportSession) in
guard let session = exportSession else {
// Error
return
}
switch session.status {
case .completed:
guard NSData(contentsOf: outputURL) != nil else {
// Error
return
}
// Now you can find the video with the watermark in the location outputURL
default:
// Error
}
})
Let me know if this code works for you.
It is in swift 3 so some changes will be needed.
I currently am using this code on an app of mine. Have not updated it to swift 5 yet
I do not have an actual development environment for Swift that can utilize AVFoundation. Thus, I can't provide you with any example code.
For adding meta data(date, location, timestamp, watermark, frame rate, etc...) as an overlay to the video while recording, you would have to process the video feed, frame by frame, live, while recording. Most likely you would have to store the frames in a buffer and process them before actually record them.
Now when it come to the meta data, there are two type, static and dynamic. For static type such as a watermark, it should be easy enough, as all the frames will get the same thing.
However, for dynamic meta data type such as timestamp or GPS location, there are a few things that needed to be taken into consideration. It takes computational power and time to process the video frames. Thus, depends on the type of dynamic data and how you got them, sometime the processed value may not be a correct value. For example, if you got a frame at 1:00:01, you process it and add a timestamp to it. Just pretend that it took 2 seconds to process the timestamp. The next frame you got is at 1:00:02, but you couldn't process it until 1:00:03 because processing the previous frame took 2 seconds. Thus, depend on how you got that new timestamp for the new frame, that timestamp value may not be the value that you wanted.
For processing dynamic meta data, you should also take into consideration of hardware lag. For example, the software is supposed to add live GPS location data to each frame and there weren't any lags in development or in testing. However, in real life, a user used the software in an area with a bad connection, and his phone lag while obtaining his GPS location. Some of his lags lasted as long as 5 seconds. What do you do in that situation? Do you set a time out for the GPS location and used the last good position? Do you report the error? Do you defer that frame to be process later when the GPS data become available(This may ruin live recording) and using an expensive algorithm to try to predict the user's location for that frame?
Besides those to take into consideration, I have some references here that I think may help you. I thought the one from medium.com looked pretty good.
https://medium.com/ios-os-x-development/ios-camera-frames-extraction-d2c0f80ed05a
Adding watermark to currently recording video and save with watermark
Render dynamic text onto CVPixelBufferRef while recording video
Adding on to #Kevin Ng, you can do an overlay on video frames with an UIViewController and an UIView.
UIViewController will have:
property to work with video stream
private var videoSession: AVCaptureSession?
property to work with overlay(the UIView class)
private var myOverlay: MyUIView{view as! MyUIView}
property to work with video output queue
private let videoOutputQueue = DispatchQueue(label:
"outputQueue", qos: .userInteractive)
method to create video session
method to process and display overlay
UIView will have task-specific helper methods needed to to act as overlay. For example, if you are doing hand detection, this overlay class can have helper methods to draw points on coordinates(ViewController class will detect coordinates of hand features, do necessary coordinate conversions, then pass the coordinates to the UIView class to display coordinates as an overlay)
I have my camera's output going through a UIImageView's image so that a filter effect can be applied to it in real time. How do I capture the video output that I'm seeing in real time? I want to start recording for as long as I want, then stop the recording and have the resulting video stored somewhere temporary so that I can later save it to my camera roll.
My real issue that I'm unfamiliar with is capturing the UIImageView as video.
For example, I can see the video output with my function that is changing the UIImageView:
func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection){
if(captureOutput){
let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)
let cameraImage = CIImage(cvPixelBuffer: pixelBuffer!)
image = UIImage(ciImage: cameraImage)
if let ciImage = image?.ciImage {
image = filterImage(with:ciImage, filterDeg:hueDeg)
var orientation = UIImageOrientation.right
if(isFrontCamera){
orientation = UIImageOrientation.leftMirrored
}
image = UIImage(cgImage: (image?.cgImage)!, scale: 1.0, orientation: orientation)
}
DispatchQueue.main.async(){
imageView!.image = image
}
}
}
But how can I start actually recording the UIImageView as saved video?