Extract thumbnail from video url

Question

I have to extract a thumbnail from a video (from url) and I use this code:

NSString *stringUrl = video.stringurl;
NSURL *url = [NSURL URLWithString:stringUrl];

AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:url options:nil];
AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc]initWithAsset:asset];
[imageGenerator setRequestedTimeToleranceBefore:kCMTimeZero];
[imageGenerator setRequestedTimeToleranceAfter:kCMTimeZero];

CGImageRef imageRef = [imageGenerator copyCGImageAtTime:playerCurrentTime actualTime:&actualtime error:&error];
UIImage *thumbnail = [UIImage imageWithCGImage:imageRef];

CGImageRelease(imageRef);

But sometime I have an error with copyCGImageAtTime and the thumbnail is not generated. The error is: Error save image Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed"(OSStatus error -12792.)", NSLocalizedFailureReason=An unknown error occurred (-12792)}

Here is the link which I have read a solution but if a use fileURLWithPath: instead of URLWithString: the method add to the end of the url an "-- file://localhost/" that invalidates the url. So I don't know what I can do.

@anna565 Did you find a solution ? I have the same error but can't figure out why it occurs. — Sam, May 22 '16 at 11:38
@aykutt Did you find a solution ? I have the same error but can't figure out why it occurs. — Sam, May 22 '16 at 11:38

Bhavin · Answer 1 · 2013-09-09T13:59:06.463

5

If you are using MPMoviePlayerController then you can use this code to generate thumbnail from video URL.

NSString *stringUrl = video.stringurl;
NSURL *url = [NSURL URLWithString:stringUrl];
MPMoviePlayerController *player = [[MPMoviePlayerController alloc] initWithContentURL:url];
UIImage *thumbnail = [player thumbnailImageAtTime:1.0 timeOption:MPMovieTimeOptionNearestKeyFrame];

But, using this code, player will start autoplaying audio. So, you have to stop the player with this code :

//Player autoplays audio on init
[player stop];

Update :

Error save image Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed"(OSStatus error -12792.)", NSLocalizedFailureReason=An unknown error occurred (-12792)}

The Error is probably due to use of URLWithString. I think you should use -fileURLWithPath instead of URLWithString.

Sample Code :

NSString *stringUrl = video.stringurl;
NSURL *vidURL = [NSURL fileURLWithPath:stringUrl];

AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:vidURL options:nil];
AVAssetImageGenerator *generate = [[AVAssetImageGenerator alloc] initWithAsset:asset];

NSError *err = NULL;
CMTime time = CMTimeMake(1, 60);

CGImageRef imgRef = [generate copyCGImageAtTime:time actualTime:NULL error:&err];
UIImage *thumbnail = [UIImage imageWithCGImage:imgRef];

edited Sep 09 '13 at 13:59

answered Sep 09 '13 at 13:27

Bhavin

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Thank you but I already have an AVPlayer, not a MPMoviePlayer – Anna565 Sep 09 '13 at 13:29
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@Anna565 : Check **Update** in my Answer. – Bhavin Sep 09 '13 at 13:34
1

I know how I can extract a thumbnail from an AVPlayer, the problem is that the method that I use sometimes works but sometimes gives an error. This is the problem – Anna565 Sep 09 '13 at 13:40
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@Anna565 : Check Last Line in my Answer. – Bhavin Sep 09 '13 at 13:50
1

Yes but if a use fileURLWithPath: instead of URLWithString: the method add to the end of the url an "-- file://localhost/" that invalidates the url. – Anna565 Sep 09 '13 at 13:59
1

@Anna565 Same problem with the error. I use AVPlayer and some thumbnails does not work and create this error. Did you find out why Anna? – Sam May 22 '16 at 11:40

Vaiden · Answer 2 · 2016-05-23T14:34:41.647

I'm trying as well to grab a screenshot from an HLS variable bitrate stream, I.E. M3U8, and none of the methods provided here worked for me.

I did succeed at the end. First you need to attach an AVPlayerItemVideoOutput to your player:

 self.playerAV = [AVPlayer playerWithURL:localURL];

    NSDictionary* settings = @{ (id)kCVPixelBufferPixelFormatTypeKey : [NSNumber numberWithInt:kCVPixelFormatType_32BGRA] };
    AVPlayerItemVideoOutput* output = [[AVPlayerItemVideoOutput alloc] initWithPixelBufferAttributes:settings];
    [self.playerAV.currentItem addOutput:output];

Now when you wanna grab the screenshot:

  CVPixelBufferRef pixelBuffer = [output copyPixelBufferForItemTime:player.currentTime itemTimeForDisplay:nil];
            CIImage *ciImage = [CIImage imageWithCVPixelBuffer:pixelBuffer];

            CIContext *temporaryContext = [CIContext contextWithOptions:nil];
            CGImageRef videoImage = [temporaryContext
                                     createCGImage:ciImage
                                     fromRect:CGRectMake(0, 0,
                                                         CVPixelBufferGetWidth(pixelBuffer),
                                                         CVPixelBufferGetHeight(pixelBuffer))];

            image = [UIImage imageWithCGImage:videoImage];
            image = [image cropImageToSize:maxSize withProportionDiffLargerThan:IMAGE_PROPORTION_DIFF];

            if ( videoImage )
            {
                CGImageRelease(videoImage);
            }

treid this, but its not working!! i am using hls Any idea what is the issue? — IamDev, Dec 23 '16 at 07:12
What do you mean by "not working"? What OS version? What device? — Vaiden, Dec 24 '16 at 16:45

score 3 · Answer 3 · answered Feb 17 '17 at 15:34

AVAssetImageGenerator does not work for HSL videos.

I was able to get an image from the HSL video using the sample code below.

Sample code :

CMTime currentTime = _player.currentItem.currentTime;
CVPixelBufferRef buffer = [_videoOutput copyPixelBufferForItemTime:currentTime itemTimeForDisplay:nil];
CIImage *ciImage = [CIImage imageWithCVPixelBuffer:buffer];
UIImage *thumbImage = [UIImage imageWithCIImage:ciImage];

score 2 · Answer 4 · answered Sep 09 '13 at 13:26

2

on one of my app i've captured an image from the video url like this:

MPMoviePlayerController *player = [[[MPMoviePlayerController alloc] initWithContentURL:videoURL]autorelease];
UIImage  *thumbnail = [player thumbnailImageAtTime:0.0 timeOption:MPMovieTimeOptionNearestKeyFrame];

just passing the url object as videoURL and with the use of MPMoviePlayerController i successfully able to have the image all the time. hope you too will be able to do this with this simple code

answered Sep 09 '13 at 13:26

D-eptdeveloper

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you should have specified that... added the tag. – John Riselvato Sep 09 '13 at 13:31
1

Sorry I have added the tag – Anna565 Sep 09 '13 at 13:41

score 2 · Answer 5 · answered Sep 09 '13 at 13:32

2

If you are using AVPlayer, you can get the thumbnail like this:

AVAsset *asset = [AVAsset assetWithURL:sourceURL];
AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc]initWithAsset:asset];
CMTime time = CMTimeMake(1, 1);
CGImageRef imageRef = [imageGenerator copyCGImageAtTime:time actualTime:NULL error:NULL];
UIImage *thumbnail = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);  // CGImageRef won't be released by ARC

answered Sep 09 '13 at 13:32

John Riselvato

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This is exactly the same code that I have used and sometimes works, but sometimes I have an error and the thumbnail is not generated – Anna565 Sep 09 '13 at 13:46
@Anna565 yes sometimes it works and sometimes it does not.. Why this error? – Sam May 22 '16 at 11:41
@sam, I'm unsure. Have you tried async and then returning on the mail thread? – John Riselvato May 24 '16 at 14:55

score 1 · Answer 6 · answered Sep 20 '19 at 12:26

I was able to solve the same by using the following approach.

Swift 4.1

func createThumbnailForVideo(atURL videoURL: URL , completion : @escaping (UIImage?)->Void) {
    let asset = AVAsset(url: videoURL)
    let assetImgGenerate = AVAssetImageGenerator(asset: asset)
    assetImgGenerate.appliesPreferredTrackTransform = true
    let time = CMTimeMakeWithSeconds(1, preferredTimescale: 60)
    let times = [NSValue(time: time)]
    assetImgGenerate.generateCGImagesAsynchronously(forTimes: times, completionHandler: {  _, image, _, _, _ in
        if let image = image {
            let uiImage = UIImage(cgImage: image)
            completion(uiImage)
        } else {
            completion(nil)
        }
    })
}

Thank you!!! this answer has solved similar problem that appear on slow internet connection, but i should to call completion handler in DispatchQueue.main.async — Dmitriy Grachev, Jul 22 '20 at 21:02

Extract thumbnail from video url

6 Answers6

Sample code :

Linked