获取视频文件第一帧图片

+ (UIImage*) thumbnailImageForVideo:(NSString *)videoPath

{

    

    if(videoPath.length ==0)

    {

        returnnil;

    }

    

    NSURL *videoURL = [NSURLfileURLWithPath:videoPath];

    AVURLAsset *asset = [[AVURLAssetalloc] initWithURL:videoURLoptions:nil];

    NSParameterAssert(asset);

    AVAssetImageGenerator *assetImageGenerator = [[AVAssetImageGeneratoralloc] initWithAsset:asset];

    assetImageGenerator.appliesPreferredTrackTransform =YES;

    assetImageGenerator.apertureMode =AVAssetImageGeneratorApertureModeEncodedPixels;

    

    CGImageRef thumbnailImageRef =NULL;  

    CFTimeInterval thumbnailImageTime =0;  

    NSError *thumbnailImageGenerationError =nil;  

    thumbnailImageRef = [assetImageGenerator copyCGImageAtTime:CMTimeMake(thumbnailImageTime,15) actualTime:NULLerror:&thumbnailImageGenerationError];  

     

    

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

    //NSData *imageData = UIImagePNGRepresentation(thumbnailImage);

CGImageRelease(thumbnailImageRef);

    return thumbnailImage;

}