Get UIImage from the CALayer attached to AVPlayer (extract frame from video playing)

I play a video with AVPlayer. It works ok.

Now I want to get a UIImage from the video playing (when I push a button for the moment).

Attached to my AVPlayer there is a CALayer that is used to display video on my UIView. My idea is to get an UIImage from CALayer during video is playing.

I do this with code from another question:

UIImage from CALayer - iPhone SDK

However my UIImage is empty. The resolution is good but it is but fully white !!!

It seems that vi开发者_运维知识库deo doesn't write the contents of my CALayer.

Someone can help me? Thanks

---

I couldn't get Meet's solution to work for me, but it got me thinking in the right direction.

Below is the code that I ended up using in my project. The method screenshotFromPlayer:maximumSize: accepts an instance of an AVPlayer from which to take a screenshot, and a CGSize that will be the returned image's maximum size.

- (UIImage *)screenshotFromPlayer:(AVPlayer *)player maximumSize:(CGSize)maxSize {

    CMTime actualTime;
    NSError *error;

    AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc] initWithAsset:player.currentItem.asset];

    // Setting a maximum size is not necessary for this code to 
    // successfully get a screenshot, but it was useful for my project.
    generator.maximumSize = maxSize;

    CGImageRef cgIm = [generator copyCGImageAtTime:player.currentTime 
                                        actualTime:&actualTime 
                                             error:&error];
    UIImage *image = [UIImage imageWithCGImage:cgIm];
    CFRelease(cgIm);

    if (nil != error) {
        NSLog(@"Error making screenshot: %@", [error localizedDescription]);
        NSLog(@"Actual screenshot time: %f Requested screenshot time: %f", CMTimeGetSeconds(actualTime),
          CMTimeGetSeconds(self.recordPlayer.currentTime));
        return nil;
    }

    return image;
}

Note also that one could use the method generateCGImagesAsynchronouslyForTimes:completionHandler: instead of copyCGImageAtTime:actualTime:error: (on the instance of AVAssetImageGenerator) to perform the image generation asynchronously.

This code sample generates a screenshot at the AVPlayer's currentTime, but any time could be used instead.

---

The code to get image from avplayer.

 - (UIImage *)currentItemScreenShot
{
    AVPlayer *abovePlayer = [abovePlayerView player];
    CMTime time = [[abovePlayer currentItem] currentTime];
    AVAsset *asset = [[[abovePlayerView player] currentItem] asset];
    AVAssetImageGenerator *imageGenerator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
    if ([imageGenerator respondsToSelector:@selector(setRequestedTimeToleranceBefore:)] && [imageGenerator respondsToSelector:@selector(setRequestedTimeToleranceAfter:)]) {
        [imageGenerator setRequestedTimeToleranceBefore:kCMTimeZero];
        [imageGenerator setRequestedTimeToleranceAfter:kCMTimeZero];
    }
    CGImageRef imgRef = [imageGenerator copyCGImageAtTime:time
                                          actualTime:NULL
                                               error:NULL];
    if (imgRef == nil) {
        if ([imageGenerator respondsToSelector:@selector(setRequestedTimeToleranceBefore:)] && [imageGenerator respondsToSelector:@selector(setRequestedTimeToleranceAfter:)]) {
            [imageGenerator setRequestedTimeToleranceBefore:kCMTimePositiveInfinity];
            [imageGenerator setRequestedTimeToleranceAfter:kCMTimePositiveInfinity];
        }
        imgRef = [imageGenerator copyCGImageAtTime:time actualTime:NULL error:NULL];
    }
    UIImage *image = [[UIImage alloc] initWithCGImage:imgRef];
    CGImageRelease(imgRef);
    [imageGenerator release];

    return [image autorelease];
}

set [imageGenerator setRequestedTimeToleranceBefore:kCMTimeZero] and [imageGenerator setRequestedTimeToleranceAfter:kCMTimeZero] if you need precise time.

---

Try to get the image from the video file at specified instance using the AVAssetImageGenerator:

    AVURLAsset *asset=[[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath:[info objectForKey:@"UIImagePickerControllerReferenceURL"]] options:nil];
    AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
    generator.appliesPreferredTrackTransform=TRUE;
    [asset release];
    CMTime thumbTime = CMTimeMakeWithSeconds(0,30);
    AVAssetImageGeneratorCompletionHandler handler = ^(CMTime requestedTime, CGImageRef im, CMTime actualTime, AVAssetImageGeneratorResult result, NSError *error){
    if (result != AVAssetImageGeneratorSucceeded) {

    }
    UIImage *thumbImg = [[UIImage imageWithCGImage:im] retain];
    [generator release];