获取相册视频并保存到指定路径

NSMutableArray *videoArray = [NSMutableArray array];
PHFetchOptions *option = [[PHFetchOptions alloc] init];
    option.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO]];
    PHFetchResult *result = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeVideo options:option];
    
    [result enumerateObjectsUsingBlock:^(PHAsset *  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        
        if (obj.mediaType == PHAssetMediaTypeVideo) {
          [videoArray addObject:obj];
        }
    }];

- (void)requestVideo:(PHAsset *)PHAsset compeletion:(void (^)(AVAsset *))compeletion {
    PHVideoRequestOptions *options = [[PHVideoRequestOptions alloc] init];
    options.version = PHImageRequestOptionsVersionCurrent;
    options.deliveryMode = PHVideoRequestOptionsDeliveryModeAutomatic;
    [[PHImageManager defaultManager] requestAVAssetForVideo:PHAsset options:options resultHandler:^(AVAsset * _Nullable asset, AVAudioMix * _Nullable audioMix, NSDictionary * _Nullable info) {
        compeletion(asset);
    }];
}

NSString *videoPath = @"";// 需要保存到路径
AVAssetExportSession *session = [AVAssetExportSession exportSessionWithAsset:asset presetName:AVAssetExportPresetHighestQuality];
        session.outputFileType = AVFileTypeMPEG4;// 输出的视频格式
        session.outputURL = [NSURL fileURLWithPath:videoPath]; // 这个就是你可以导出的文件路径了。
        
        [session exportAsynchronouslyWithCompletionHandler:^{
				保存成功后的回调        
        }];