PHAsset 获取相册中的视频url

 PHFetchOptions *options = [[PHFetchOptions alloc] init];
    options.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:YES]];
    PHFetchResult *assetsFetchResults = [PHAsset fetchAssetsWithOptions:options];
    // 这时 assetsFetchResults 中包含的，应该就是各个资源（PHAsset）
    for (NSInteger i = 0; i < assetsFetchResults.count; i++) {
        // 获取一个资源（PHAsset）
        PHAsset *phAsset = assetsFetchResults[i];
        if (phAsset.mediaType == PHAssetMediaTypeVideo) {
            PHVideoRequestOptions *options = [[PHVideoRequestOptions alloc] init];
            options.version = PHImageRequestOptionsVersionCurrent;
            options.deliveryMode = PHVideoRequestOptionsDeliveryModeAutomatic;
            
            PHImageManager *manager = [PHImageManager defaultManager];
            [manager requestAVAssetForVideo:phAsset options:options resultHandler:^(AVAsset * _Nullable asset, AVAudioMix * _Nullable audioMix, NSDictionary * _Nullable info) {
                AVURLAsset *urlAsset = (AVURLAsset *)asset;
                
                NSURL *url = urlAsset.URL;
                NSData *data = [NSData dataWithContentsOfURL:url];
                
                NSLog(@"%@",data);
            }];
        }
    }