iOS开发之GIF转MP4

前言

最近遇到需要将gif转化为mp4的问题，网上找的在线转换限制太多，索性就自己写了一个工具APP。文章末尾有开源代码和打包好的APP，如有需要请自行下载。

效果图

核心代码

import ImageIO

#if os(iOS)

import MobileCoreServices

#elseif os(OSX)

import CoreServices

#endif

class GIF {

    private let frameDelayThreshold = 0.02

    private(set) var duration = 0.0

    private(set) var imageSource: CGImageSource!

    private(set) var frames: [CGImage?]!

    private(set) lazy var frameDurations = [TimeInterval]()

    var size: CGSize {

        guard let f = frames.first, let cgImage = f else { return .zero }

        return CGSize(width: cgImage.width, height: cgImage.height)

    }

    private lazy var getFrameQueue: DispatchQueue = DispatchQueue(label: "gif.frame.queue", qos: .userInteractive)

    init?(data: Data) {

        guard let imgSource = CGImageSourceCreateWithData(data as CFData, nil), let imgType = CGImageSourceGetType(imgSource), UTTypeConformsTo(imgType, kUTTypeGIF) else {

            return nil

        }

        self.imageSource = imgSource

        let imgCount = CGImageSourceGetCount(imageSource)

        frames = [CGImage?](repeating: nil, count: imgCount)

        for i in 0..<imgCount {

            let delay = getGIFFrameDuration(imgSource: imageSource, index: i)

            frameDurations.append(delay)

            duration += delay

            getFrameQueue.async { [unowned self] in

                self.frames[i] = CGImageSourceCreateImageAtIndex(self.imageSource, i, nil)

            }

        }

    }

    func getFrame(at index: Int) -> CGImage? {

        if index >= CGImageSourceGetCount(imageSource) {

            return nil

        }

        if let frame = frames[index] {

            return frame

        } else {

            let frame = CGImageSourceCreateImageAtIndex(imageSource, index, nil)

            frames[index] = frame

            return frame

        }

    }

    private func getGIFFrameDuration(imgSource: CGImageSource, index: Int) -> TimeInterval {

        guard let frameProperties = CGImageSourceCopyPropertiesAtIndex(imgSource, index, nil) as? [String: Any],

            let gifProperties = frameProperties[kCGImagePropertyGIFDictionary as String] as? NSDictionary,

            let unclampedDelay = gifProperties[kCGImagePropertyGIFUnclampedDelayTime] as? TimeInterval

            else { return 0.02 }

        var frameDuration = TimeInterval(0)

        if unclampedDelay < 0 {

            frameDuration = gifProperties[kCGImagePropertyGIFDelayTime] as? TimeInterval ?? 0.0

        } else {

            frameDuration = unclampedDelay

        }

        /* Implement as Browsers do: Supports frame delays as low as 0.02 s, with anything below that being rounded up to 0.10 s.

         http://nullsleep.tumblr.com/post/16524517190/animated-gif-minimum-frame-delay-browser-compatibility */

        if frameDuration < frameDelayThreshold - Double.ulpOfOne {

            frameDuration = 0.1

        }

        return frameDuration

    }

}

#if os(iOS)

import UIKit

#elseif os(OSX)

import Cocoa

#endif

import Foundation

import AVFoundation

class GIF2MP4 {

    private(set) var gif: GIF

    private var outputURL: URL!

    private(set) var videoWriter: AVAssetWriter!

    private(set) var videoWriterInput: AVAssetWriterInput!

    private(set) var pixelBufferAdaptor: AVAssetWriterInputPixelBufferAdaptor!

    var videoSize: CGSize {

        //The size of the video must be a multiple of 16

        return CGSize(width: max(1, floor(gif.size.width / 16)) * 16, height: max(1, floor(gif.size.height / 16)) * 16)

    }

    init?(data: Data) {

        guard let gif = GIF(data: data) else { return nil }

        self.gif = gif

    }

    private func prepare() {

        try? FileManager.default.removeItem(at: outputURL)

        let avOutputSettings: [String: Any] = [

            AVVideoCodecKey: AVVideoCodecType.h264,

            AVVideoWidthKey: NSNumber(value: Float(videoSize.width)),

            AVVideoHeightKey: NSNumber(value: Float(videoSize.height))

        ]

        let sourcePixelBufferAttributesDictionary = [

            kCVPixelBufferPixelFormatTypeKey as String: NSNumber(value: kCVPixelFormatType_32ARGB),

            kCVPixelBufferWidthKey as String: NSNumber(value: Float(videoSize.width)),

            kCVPixelBufferHeightKey as String: NSNumber(value: Float(videoSize.height))

        ]

        videoWriter = try! AVAssetWriter(outputURL: outputURL, fileType: AVFileType.mp4)

        videoWriterInput = AVAssetWriterInput(mediaType: AVMediaType.video, outputSettings: avOutputSettings)

        videoWriter.add(videoWriterInput)

        pixelBufferAdaptor = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: videoWriterInput, sourcePixelBufferAttributes: sourcePixelBufferAttributesDictionary)

        videoWriter.startWriting()

        videoWriter.startSession(atSourceTime: CMTime.zero)

    }

    func convertAndExport(to url: URL, completion: @escaping (Bool) -> Void ) {

        outputURL = url

        prepare()

        var index = 0

        var delay = 0.0 - gif.frameDurations[0]

        let queue = DispatchQueue(label: "mediaInputQueue")

        videoWriterInput.requestMediaDataWhenReady(on: queue) {

            var isFinished = true

            var isSuccess = true

            while index < self.gif.frames.count {

                if self.videoWriterInput.isReadyForMoreMediaData == false {

                    isFinished = false

                    break

                }

                if let cgImage = self.gif.getFrame(at: index) {

                    let frameDuration = self.gif.frameDurations[index]

                    delay += Double(frameDuration)

                    let presentationTime = CMTime(seconds: delay, preferredTimescale: 600)

                    let result = self.addImage(image: cgImage, withPresentationTime: presentationTime)

                    if result == false {

                        isSuccess = false

                        break

                    } else {

                        index += 1

                    }

                }

            }

            if isFinished {

                self.videoWriterInput.markAsFinished()

                self.videoWriter.finishWriting {

                    DispatchQueue.main.async {

                        completion(isSuccess)

                    }

                }

            } else {

                // Fall through. The closure will be called again when the writer is ready.

            }

        }

    }

    private func addImage(image: CGImage, withPresentationTime presentationTime: CMTime) -> Bool {

        guard let pixelBufferPool = pixelBufferAdaptor.pixelBufferPool else {

            print("pixelBufferPool is nil ")

            return false

        }

        let pixelBuffer = pixelBufferFromImage(image: image, pixelBufferPool: pixelBufferPool, size: videoSize)

        return pixelBufferAdaptor.append(pixelBuffer, withPresentationTime: presentationTime)

    }

    private func pixelBufferFromImage(image: CGImage, pixelBufferPool: CVPixelBufferPool, size: CGSize) -> CVPixelBuffer {

        var pixelBufferOut: CVPixelBuffer?

        let status = CVPixelBufferPoolCreatePixelBuffer(kCFAllocatorDefault, pixelBufferPool, &pixelBufferOut)

        if status != kCVReturnSuccess {

            fatalError("CVPixelBufferPoolCreatePixelBuffer() failed")

        }

        let pixelBuffer = pixelBufferOut!

        CVPixelBufferLockBaseAddress(pixelBuffer, CVPixelBufferLockFlags(rawValue: CVOptionFlags(0)))

        let data = CVPixelBufferGetBaseAddress(pixelBuffer)

        let rgbColorSpace = CGColorSpaceCreateDeviceRGB()

        let context = CGContext(data: data, width: Int(size.width), height: Int(size.height),

                                bitsPerComponent: 8, bytesPerRow: CVPixelBufferGetBytesPerRow(pixelBuffer), space: rgbColorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedFirst.rawValue)!

        context.clear(CGRect(x: 0, y: 0, width: size.width, height: size.height))

        let horizontalRatio = size.width / CGFloat(image.width)

        let verticalRatio = size.height / CGFloat(image.height)

        let aspectRatio = max(horizontalRatio, verticalRatio) // ScaleAspectFill

        //let aspectRatio = min(horizontalRatio, verticalRatio) // ScaleAspectFit

        let newSize = CGSize(width: CGFloat(image.width) * aspectRatio, height: CGFloat(image.height) * aspectRatio)

        let x = newSize.width < size.width ? (size.width - newSize.width) / 2: -(newSize.width-size.width)/2

        let y = newSize.height < size.height ? (size.height - newSize.height) / 2: -(newSize.height-size.height)/2

        context.draw(image, in: CGRect(x: x, y: y, width: newSize.width, height: newSize.height))

        CVPixelBufferUnlockBaseAddress(pixelBuffer, CVPixelBufferLockFlags(rawValue: CVOptionFlags(0)))

        return pixelBuffer

    }

}

使用步骤

打开APP
将gif拖拽到窗口中

常见问题

macos 10.15 将对您的电脑造成伤害，您应该将它移到废纸篓

APP右键-显示简介-覆盖恶意软件保护打勾
打开终端 codesign -f -s - --deep /Applications/appname.app

总结

代码支持iOS和macOS

下载地址----->>>GIF2MP4，如果对你有所帮助，欢迎Star。

巴特西

iOS开发之GIF转MP4

前言

效果图

核心代码

使用步骤

常见问题

总结

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