我正在尝试从视频中获取缩略图并在我的tableview中显示它。这是我的代码:
- (UIImage *)imageFromVideoURL:(NSURL *)contentURL {
AVAsset *asset = [AVAsset assetWithURL:contentURL];
// Get thumbnail at the very start of the video
CMTime thumbnailTime = [asset duration];
thumbnailTime.value = 25;
// Get image from the video at the given time
AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
CGImageRef imageRef = [imageGenerator copyCGImageAtTime:thumbnailTime actualTime:NULL error:NULL];
UIImage *thumbnail = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return thumbnail;
}
但是图像总是会变黑。怎么了?
使用此:Swift 3 -
func createThumbnailOfVideoFromFileURL(videoURL: String) -> UIImage? {
let asset = AVAsset(url: URL(string: videoURL)!)
let assetImgGenerate = AVAssetImageGenerator(asset: asset)
assetImgGenerate.appliesPreferredTrackTransform = true
let time = CMTimeMakeWithSeconds(Float64(1), 100)
do {
let img = try assetImgGenerate.copyCGImage(at: time, actualTime: nil)
let thumbnail = UIImage(cgImage: img)
return thumbnail
} catch {
return UIImage(named: "ico_placeholder")
}
}
重要的提示 :
你需要在if else中使用它,因为它是资源广泛的。您必须将图像存储在数组或模型中,并检查一旦创建了缩略图,它就会引用缓存/数组,以便cellForRowAtIndexPath
不会导致滚动UITableView
的延迟
只需使用此代码..传递您的视频网址并获取图片。
+(UIImage *)getPlaceholderImageFromVideo:(NSString *)videoURL {
NSURL *url = [NSURL URLWithString:videoURL];
AVAsset *asset = [AVAsset assetWithURL:url];
AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
CMTime time = [asset duration];
time.value = 0;
CGImageRef imageRef = [imageGenerator copyCGImageAtTime:time actualTime:NULL error:NULL];
UIImage *thumbnail = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return thumbnail;
}
希望,这是你正在寻找的。任何关注都会回复给我。 :)
//(Local URL)
NSURL *videoURL = [NSURL fileURLWithPath:filepath];// filepath is your video file path
AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:videoURL options:nil];
AVAssetImageGenerator *generateImg = [[AVAssetImageGenerator alloc] initWithAsset:asset];
NSError *error = NULL;
CMTime time = CMTimeMake(1, 1);
CGImageRef refImg = [generateImg copyCGImageAtTime:time actualTime:NULL error:&error];
NSLog(@"error==%@, Refimage==%@", error, refImg);
UIImage *frameImage= [[UIImage alloc] initWithCGImage:refImg];
return frameImage;
请查看“从视频生成缩略图”链接
https://littlebitesofcocoa.com/115-generating-thumbnails-from-videos
应用程序需要显示视频内容的一个或多个缩略图(小型静态图像预览),这是很常见的。但是,根据视频的来源,我们可能无法轻松访问预制缩略图。让我们看一下如何使用AVAssetImageGenerator来获取我们自己的东西。我们从视频的简单NSURL开始,这可以是本地的或远程的。我们将用它创建一个AVAsset,并创建一个新的AVAssetImageGenerator对象。我们将配置生成器以应用首选变换,以使我们的缩略图处于正确的方向。
import AVFoundation
if let asset = AVAsset(URL: videoURL) {
let durationSeconds = CMTimeGetSeconds(asset.duration)
let generator = AVAssetImageGenerator(asset: asset)
generator.appliesPreferredTrackTransform = true
let time = CMTimeMakeWithSeconds(durationSeconds/3.0, 600)
var thumbnailImage: CGImageRef
generator.generateCGImagesAsynchronouslyForTimes([NSValue(CMTime: time)]) {
(requestedTime: CMTime, thumbnail: CGImage?, actualTime: CMTime, result: AVAssetImageGeneratorResult, error: NSError?) in
self.videoThumbnailImageView.image = UIImage(CGImage: thumbnail)
}
}
Swift 4代码@Disha的回答:
let imageGenerator = AVAssetImageGenerator(asset: avAsset)
let time = CMTime(seconds: seconds, preferredTimescale: 600)
let times = [NSValue(time: time)]
imageGenerator.generateCGImagesAsynchronously(forTimes: times, completionHandler: {
requestedTime, image, actualTime, result, error in
guard let cgImage = image else
{
print("No image!")
return
}
let uiImage = UIImage(cgImage: cgImage)
UIImageWriteToSavedPhotosAlbum(uiImage, nil, nil, nil);
})
使用Swift 5作为AVAsset的扩展函数:
import AVKit
extension AVAsset {
func generateThumbnail(completion: @escaping (UIImage?) -> Void) {
DispatchQueue.global().async {
let imageGenerator = AVAssetImageGenerator(asset: self)
let time = CMTime(seconds: 0.0, preferredTimescale: 600)
let times = [NSValue(time: time)]
imageGenerator.generateCGImagesAsynchronously(forTimes: times, completionHandler: { _, image, _, _, _ in
if let image = image {
completion(UIImage(cgImage: image))
} else {
completion(nil)
}
})
}
}
}
用法:
AVAsset(url: url).generateThumbnail { [weak self] (image) in
DispatchQueue.main.async {
guard let image = image else { return }
self?.imageView.image = image
}
}
func getThumbnailFrom(path: URL) -> UIImage? {
do {
let asset = AVURLAsset(url: path , options: nil)
let imgGenerator = AVAssetImageGenerator(asset: asset)
imgGenerator.appliesPreferredTrackTransform = true
let timestamp = asset.duration
print("Timestemp: \(timestamp)")
let cgImage = try imgGenerator.copyCGImage(at: timestamp, actualTime: nil)
let thumbnail = UIImage(cgImage: cgImage)
return thumbnail
} catch let error {
print("*** Error generating thumbnail: \(error.localizedDescription)")
return nil
}
}
本准则正在运作。