降低视频的帧率以在Swift中获得GIF效果

import AVFoundation

let url = Bundle.main.url(forResource: "video", withExtension: "mp4")!
let asset = AVAsset(url: url)

let imageGenerator = AVAssetImageGenerator(asset: asset)

imageGenerator.appliesPreferredTrackTransform = true
imageGenerator.maximumSize = CGSize(width: 480, height: 320)

var images: [UIImage] = []

let duration = asset.duration
let durationInSeconds = CMTimeGetSeconds(duration)
let frameRate = 10 // 设置帧率为10帧/秒
let totalFrames = Int(durationInSeconds) * frameRate

for i in 0..<totalFrames {
    let time = CMTimeMake(value: Int64(i), timescale: Int32(frameRate))
    if let cgImage = try? imageGenerator.copyCGImage(at: time, actualTime: nil) {
        let image = UIImage(cgImage: cgImage)
        images.append(image)
    }
}

let gifURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("animated.gif")
guard let destination = CGImageDestinationCreateWithURL(gifURL as CFURL, kUTTypeGIF, images.count, nil) else { return }

let frameProperties = [kCGImagePropertyGIFDictionary as String: [kCGImagePropertyGIFDelayTime as String: 0.1]] // 设置每帧的延迟时间为0.1秒

let gifProperties = [kCGImagePropertyGIFDictionary as String: [kCGImagePropertyGIFLoopCount as String: 0]] // 设置循环次数为无限循环

CGImageDestinationSetProperties(destination, gifProperties as CFDictionary)

for image in images {
    CGImageDestinationAddImage(destination, image.cgImage!, frameProperties as CFDictionary)
}

CGImageDestinationFinalize(destination)