17

我用 AVPlayer 播放视频。它工作正常。

现在我想UIImage从视频播放中获得一个（当我按下按钮时）。

附在我的AVPlayer有一个CALayer用于在我的UIView. 我的想法是在视频播放期间获得一个UIImagefrom 。CALayer

我用另一个问题的代码来做到这一点：

来自 CALayer 的 UIImage - iPhone SDK

然而我UIImage是空的。分辨率很好，但它是全白的！

看来视频没有写我的内容CALayer。

有人可以帮助我吗？谢谢

4

3 回答 3

8

从 avplayer 获取图像的代码。

 - (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];
}

设置[imageGenerator setRequestedTimeToleranceBefore:kCMTimeZero]，[imageGenerator setRequestedTimeToleranceAfter:kCMTimeZero]如果你需要精确的时间。

于 2012-11-02T11:42:09.030 回答
8

我无法让 Meet 的解决方案为我工作，但它让我朝着正确的方向思考。

下面是我最终在我的项目中使用的代码。该方法screenshotFromPlayer:maximumSize:接受一个AVPlayer用于截取屏幕截图的实例，以及一个CGSize将是返回图像的最大尺寸的实例。

- (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;
}

另请注意，可以使用该方法generateCGImagesAsynchronouslyForTimes:completionHandler:而不是copyCGImageAtTime:actualTime:error:（在 的实例上AVAssetImageGenerator）异步执行图像生成。

AVPlayer此代码示例在's处生成屏幕截图currentTime，但可以随时使用。

于 2012-09-13T21:40:22.967 回答
1

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];
于 2012-06-22T10:50:39.707 回答