Swift - get all frames from video - ios

Question

I am following this code to get all frames from video. In this link he is trying to get a frame at a specific time. But I need to get all frames. Here is my code...
var mutableVideoURL = NSURL()
var videoFrames = [UIImage]()
let asset : AVAsset = AVAsset(url: self.mutableVideoURL as URL)
let mutableVideoDuration = CMTimeGetSeconds(asset.duration)
print("-----Mutable video duration = \(mutableVideoDuration)")
let mutableVideoDurationIntValue = Int(mutableVideoDuration)
print("-----Int value of mutable video duration = \(mutableVideoDurationIntValue)")
for index in 0..<mutableVideoDurationIntValue {
self.generateFrames(url: self.mutableVideoURL, fromTime: Float64(index))
}
func generateFrames(url : NSURL, fromTime:Float64) {
let asset: AVAsset = AVAsset(url: url as URL)
let assetImgGenerate : AVAssetImageGenerator = AVAssetImageGenerator(asset: asset)
assetImgGenerate.appliesPreferredTrackTransform = true
let time : CMTime = CMTimeMakeWithSeconds(fromTime, 600)
var img: CGImage?
do {
img = try assetImgGenerate.copyCGImage(at:time, actualTime: nil)
} catch {
}
if img != nil {
let frameImg: UIImage = UIImage(cgImage: img!)
UIImageWriteToSavedPhotosAlbum(frameImg, nil, nil, nil)//I saved here to check
videoFrames.append(frameImg)
print("-----Array of video frames *** \(videoFrames)")
} else {
print("error !!!")
}
}
I tested this code with 2 videos(length of the videos are 5 seconds and 3.45 minutes). This code works perfectly with the small duration(video length: 5 seconds) and with long duration (video length: 3.45 minutes), NSLog shows Message from debugger: Terminated due to memory issue
Any assistance would be appreciated.

Answer 1

When generating more than 1 frame Apple recommends using the method:
generateCGImagesAsynchronously(forTimes:completionHandler:)
Still, if you prefer to follow your current approach there are a couple of improvements you could do to reduce memory usage:
You are instantiating AVAsset and AVAssetImageGenerator inside the loop, you could instantiate them just once and send it to the method generateFrames.
Remove the line
UIImageWriteToSavedPhotosAlbum(frameImg, nil, nil, nil)//I saved here to check
because you are saving every frame in the photos
album, that takes extra memory.
Final result could look like this:
var videoFrames:[UIImage] = [UIImage]
let asset:AVAsset = AVAsset(url:self.mutableVideoURL as URL)
let assetImgGenerate:AVAssetImageGenerator = AVAssetImageGenerator(asset:asset)
assetImgGenerate.appliesPreferredTrackTransform = true
let duration:Float64 = CMTimeGetSeconds(asset.duration)
let durationInt:Int = Int(mutableVideoDuration)
for index:Int in 0 ..< durationInt
{
generateFrames(
assetImgGenerate:assetImgGenerate,
fromTime:Float64(index))
}
func generateFrames(
assetImgGenerate:AVAssetImageGenerator,
fromTime:Float64)
{
let time:CMTime = CMTimeMakeWithSeconds(fromTime, 600)
let cgImage:CGImage?
do
{
cgImage = try assetImgGenerate.copyCGImage(at:time, actualTime:nil)
}
catch
{
cgImage = nil
}
guard
let img:CGImage = cgImage
else
{
continue
}
let frameImg:UIImage = UIImage(cgImage:img)
videoFrames.append(frameImg)
}
Update for Swift 4.2
var videoUrl:URL // use your own url
var frames:[UIImage]
private var generator:AVAssetImageGenerator!
func getAllFrames() {
let asset:AVAsset = AVAsset(url:self.videoUrl)
let duration:Float64 = CMTimeGetSeconds(asset.duration)
self.generator = AVAssetImageGenerator(asset:asset)
self.generator.appliesPreferredTrackTransform = true
self.frames = []
for index:Int in 0 ..< Int(duration) {
self.getFrame(fromTime:Float64(index))
}
self.generator = nil
}
private func getFrame(fromTime:Float64) {
let time:CMTime = CMTimeMakeWithSeconds(fromTime, preferredTimescale:600)
let image:CGImage
do {
try image = self.generator.copyCGImage(at:time, actualTime:nil)
} catch {
return
}
self.frames.append(UIImage(cgImage:image))
}