gistfile1.m

 // Enumerate just the photos and videos group by using ALAssetsGroupSavedPhotos.
    [library enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
        
        // Within the group enumeration block, filter to enumerate just videos.
        [group setAssetsFilter:[ALAssetsFilter allVideos]];
        
        // For this example, we're only interested in the first item.
        [group enumerateAssetsAtIndexes:[NSIndexSet indexSetWithIndex:([group numberOfAssets]-1)]
                                options:0
                             usingBlock:^(ALAsset *alAsset, NSUInteger index, BOOL *innerStop) {
                                 
                                 // The end of the enumeration is signaled by asset == nil.
                                 if (alAsset) {
                                     ALAssetRepresentation *representation = [alAsset defaultRepresentation];
                                     NSURL *url = [representation url];
                                     
                                     NSLog(@"%@", url);
                                     
                                     [_videoPlaybackView setHidden:NO];
                                     _videoPlaybackView.hidden = NO;
                                     [_player setContentURL:url];
                                     [_player setControlStyle:MPMovieControlStyleEmbedded];
                                     [_player play];
                                     
                                     //AVAsset *avAsset = [AVURLAsset URLAssetWithURL:url options:nil];
                                     // Do something interesting with the AV asset.
                                 }
                             }];
    }
                         failureBlock: ^(NSError *error) {
                             // Typically you should handle an error more gracefully than this.
                             NSLog(@"No groups");
                         }];