如何在Swift中获取从UIPickerViewController中获取的视频缩略图？

Question

我就是这样访问视频的：

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject]) {

    if let videoURL = info[UIImagePickerControllerMediaURL] as? NSURL {
        let video = NSData(contentsOfURL: videoURL)
    }
}

我想向控制器中的用户展示这个video (我不是指UIDocumentInteractionController预览这个)。我需要那个视频的缩略图，然后把这个分配给UIImageView。有可能吗？

Answer 1

最简单的答案是：

import AVFoundation

private func thumbnailForVideoAtURL(url: NSURL) -> UIImage? {

    let asset = AVAsset(URL: url)
    let assetImageGenerator = AVAssetImageGenerator(asset: asset)

    var time = asset.duration
    time.value = min(time.value, 2)

    do {
        let imageRef = try assetImageGenerator.copyCGImageAtTime(time, actualTime: nil)
        return UIImage(CGImage: imageRef)
    } catch {
        print("error")
        return nil
    }
}

Answer 2

这里是使用扩展的SWIFT3.0

import Foundation
import UIKit
import MediaPlayer

import SystemConfiguration

extension AVAsset{
    var videoThumbnail:UIImage?{

        let assetImageGenerator = AVAssetImageGenerator(asset: self)
        assetImageGenerator.appliesPreferredTrackTransform = true

        var time = self.duration
        time.value = min(time.value, 2)

        do {
            let imageRef = try assetImageGenerator.copyCGImage(at: time, actualTime: nil)
            let thumbNail = UIImage.init(cgImage: imageRef)


            print("Video Thumbnail genertated successfuly".DubugSuccess())

            return thumbNail

        } catch {

            print("error getting thumbnail video".DubugError(),error.localizedDescription)
            return nil


        }

    }
}

然后简单地从任何地方访问AVAsset/URL

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject]) {

    if let videoURL = info[UIImagePickerControllerMediaURL] as? NSURL {
        let video = NSData(contentsOfURL: videoURL)

        //Create AVAsset from url
        let ass = AVAsset(url:videoURL)

        if let videoThumbnail = ass.videoThumbnail{
          print("Success")
        }
    }
}

Answer 3

您可以使用此方法生成缩略图：

import AVFoundation

func generateThumnail(url : NSURL) -> UIImage?{
    let asset: AVAsset = AVAsset(URL: url)
    let assetImgGenerate : AVAssetImageGenerator = AVAssetImageGenerator(asset: asset)
    assetImgGenerate.appliesPreferredTrackTransform = true
    let time        : CMTime = CMTimeMake(1, 30)
    let img         : CGImageRef
    do {
        try img = assetImgGenerate.copyCGImageAtTime(time, actualTime: nil)
        let frameImg: UIImage = UIImage(CGImage: img)
        return frameImg
    } catch {

    }
    return nil
}