获取视频PHAsset对象

    PHFetchOptions *option = [[PHFetchOptions alloc] init];
    option.predicate = [NSPredicate predicateWithFormat:@"mediaType == %ld",PHAssetMediaTypeVideo];
    option.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO]];
    
    
    //fetchAssetCollectionsWithType
    PHFetchResult *smartAlbums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];
    for (PHAssetCollection *collection in smartAlbums) {
        // 有可能是PHCollectionList类的的对象，过滤掉
        if (![collection isKindOfClass:[PHAssetCollection class]]) continue;
        // 过滤空相册
        if (collection.estimatedAssetCount <= 0) continue;
        if ([self isCameraRollAlbum:collection]) {
            PHFetchResult *fetchResult = [PHAsset fetchAssetsInAssetCollection:collection options:option];
            
            [fetchResult enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
                
                PHAsset *phAsset = (PHAsset *)obj;
                //可通过此PHAsset用下边方法分别获取时常、地址及缩略图
            }];
        }
    }

//获取视频本地地址及时长

- (void)getVideoPathFromPHAsset:(PHAsset *)asset Complete:(void (^)(NSString *filePatch,NSString *dTime))result {
    PHVideoRequestOptions *options = [[PHVideoRequestOptions alloc] init];
    options.version = PHImageRequestOptionsVersionCurrent;
    options.deliveryMode = PHVideoRequestOptionsDeliveryModeAutomatic;

    [[PHImageManager defaultManager] requestAVAssetForVideo:asset options:options resultHandler:^(AVAsset * _Nullable asset, AVAudioMix * _Nullable audioMix, NSDictionary * _Nullable info) {
        
        NSString * sandboxExtensionTokenKey = info[@"PHImageFileSandboxExtensionTokenKey"];
        
        NSArray * arr = [sandboxExtensionTokenKey componentsSeparatedByString:@";"];
        
        NSString * filePath = arr[arr.count - 1];
        
        CMTime   time = [asset duration];
        int seconds = ceil(time.value/time.timescale);
        //format of minute
        NSString *str_minute = [NSString stringWithFormat:@"%d",seconds/60];
        //format of second
        NSString *str_second = [NSString stringWithFormat:@"%.2d",seconds%60];
        //format of time
        NSString *format_time = [NSString stringWithFormat:@"%@:%@",str_minute,str_second];

        result(filePath,format_time);
    }];
}

//获取视频缩略图

- (void)getVideoImageFromPHAsset:(PHAsset *)asset Complete:(void (^)(UIImage *image))resultBack{
    
    PHImageRequestOptions *option = [[PHImageRequestOptions alloc] init];
    option.resizeMode = PHImageRequestOptionsResizeModeFast;
    
    [[PHImageManager defaultManager] requestImageForAsset:asset targetSize:CGSizeMake(200, 200) contentMode:PHImageContentModeDefault options:option resultHandler:^(UIImage * _Nullable result, NSDictionary * _Nullable info) {
        
        UIImage *iamge = result;
        resultBack(iamge);
    }];
}