取得视频第一帧 HA

AVFoundationframework 

 CoreMediaframework

+ (UIImage*) thumbnailImageForVideo:(NSURL *)videoURL atTime:(NSTimeInterval)time {
    AVURLAsset *asset = [[[AVURLAsset alloc] initWithURL:videoURL options:nil] autorelease];
    NSParameterAssert(asset);
    AVAssetImageGenerator *assetImageGenerator = [[[AVAssetImageGenerator alloc] initWithAsset:asset] autorelease];
    assetImageGenerator.appliesPreferredTrackTransform = YES;
    assetImageGenerator.apertureMode = AVAssetImageGeneratorApertureModeEncodedPixels;

    CGImageRef thumbnailImageRef = NULL;
    CFTimeInterval thumbnailImageTime = time;
    NSError *thumbnailImageGenerationError = nil;
    thumbnailImageRef = [assetImageGenerator copyCGImageAtTime:CMTimeMake(thumbnailImageTime, 60) actualTime:NULL error:&thumbnailImageGenerationError];

    if (!thumbnailImageRef)
        NSLog(@"thumbnailImageGenerationError %@", thumbnailImageGenerationError);

    UIImage *thumbnailImage = thumbnailImageRef ? [[[UIImage alloc] initWithCGImage:thumbnailImageRef] autorelease] : nil;

    return thumbnailImage;

}