Loading a lottie takes a long time on iPhone7, is there a way to optimize it?

[hardyZhi]

Hello! II recently encountered a problem, loading a lottie took a long time on iPhone7 iOS15.7.8, is there a way to optimize it?

Which Version of Lottie are you using?

Lottie 4.2.0

Expected Behavior

show soon

Actual Behavior

It took several seconds to display and stuck the main thread

Animation JSON

rain.zip
here the json

[hardyZhi]

if let lottieFilePath = jsonURL {
DispatchQueue.main.async {
if let animation = LottieAnimation.filepath(lottieFilePath.path){
self.backLottieV.animation = animation
let lottieFilepathURl = lottieFilePath.deletingLastPathComponent().relativePath
let provider = FilepathImageProvider(filepath: lottieFilepathURl)
self.backLottieV.imageProvider = provider
self.backLottieV.loopMode = .repeat(MAXFLOAT)
self.backLottieV.backgroundBehavior = .pauseAndRestore
self.backLottieV.alpha = 1
self.backLottieV.play()
}else{
self.backLottieV.alpha = 0
}
}
}else{
self.backLottieV.alpha = 0
}

[calda]

Are you loading the LottieAnimation on a background thread and then dispatching back to the main thread? If not that's one good opportunity to improve things a bit.

[hardyZhi]

No, I only loaded it on the main thread. I took a look and found that the most time-consuming part was loading images.

[calda]

One area I want to investigate is moving this work to a background thread so it doesn't block the main thread. This should be possible, but we haven't tried it yet.

[hardyZhi]

The same lottie performs well on Android, but lags significantly on iOS.