[manager requestAVAssetForVideo:PHAsset
                           options:videoRequestOptions
                     resultHandler:^(AVAsset * avasset, AVAudioMix * audioMix, NSDictionary * info) {}];

avasset  可能是AVURLAsset  與 AVComposition ， 直接呼叫 【avasset URL】，當選取的視訊 是慢動作視訊，huicrash；

解決思路：

1、過濾慢動作視訊

//載入視訊
+ (void)loadVideos {
 dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    ALAssetsLibrary *videolibrary = [[ALAssetsLibrary alloc] init];
    __block NSMutableArray *reList=[NSMutableArray array];
    __block BOOL flag=true;
    [videolibrary enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
        if (group) {
            [group setAssetsFilter:[ALAssetsFilter allVideos]];
            [group enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {
                if (result) {
                    BDHKUGCVideoInfoItem *videoInfo=[[BDHKUGCVideoInfoItem alloc] init];
                    videoInfo.thumbnail = [UIImage imageWithCGImage:result.thumbnail];
                    videoInfo.videoURL = result.defaultRepresentation.url;
                    NSInteger duration = [[result valueForProperty:ALAssetPropertyDuration] integerValue];
                    videoInfo.duration = [NSDate durationWithSeconds:duration];
                    videoInfo.name = result.defaultRepresentation.filename;
                    videoInfo.size = result.defaultRepresentation.size; //Bytes
                    videoInfo.format = [result.defaultRepresentation.filename pathExtension];
                    videoInfo.creationDate = [result valueForProperty:ALAssetPropertyDate];
                    PHFetchResult *fetchResult = [PHAsset fetchAssetsWithALAssetURLs:@[videoInfo.videoURL] options:nil];
                    PHAsset *phAsset = fetchResult.firstObject;
                    [[PHImageManager defaultManager] requestAVAssetForVideo:phAsset options:nil
                                                              resultHandler:^(AVAsset *avAsset, AVAudioMix *audioMix, NSDictionary *info) {
                                                                  //視訊上傳不支援慢視訊
                                                                  if (avAsset && [avAsset isKindOfClass:[AVURLAsset class]]) {
                                                                      if(videoInfo.thumbnail && videoInfo.videoURL && duration>7) {
                                                                          [reList addObject:videoInfo];
                                                                      }
                                                                  }
                                                              }];
                }
            }];
        } else {
            //沒有更多的group時，即可認為已經載入完成。
            if(flag) {//防止重複通知
                dispatch_async(dispatch_get_main_queue(), ^{
                    //*******
                    //按建立時間倒序
                    NSSortDescriptor *creationDateDesc = [NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO];
                    NSArray *descriptorArray = [NSArray arrayWithObjects:creationDateDesc, nil];
                    NSArray *sortedArray = [reList sortedArrayUsingDescriptors: descriptorArray];
                    //*******
                    //通知返回資料
                    [[NSNotificationCenter defaultCenter] postNotificationName:@"ugc_camera_result_notif" object:sortedArray];
                });
                flag = false;
            }
        }
    } failureBlock:^(NSError *error) {
        NSLog(@"error=%@",error);
        //增加錯誤返回處理
        if(flag) {//防止重複通知
            dispatch_async(dispatch_get_main_queue(), ^{
                NSArray *sortedArray = [[NSArray alloc] init];
                //通知返回資料
                [[NSNotificationCenter defaultCenter] postNotificationName:@"ugc_camera_result_notif" object:sortedArray];
            });
            flag = false;
        }
    }];
  });
}
 

2、將選取的視訊儲存到本地，上傳視訊使用

//Output URL
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = paths.firstObject;
NSString *myPathDocs =  [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"mergeSlowMoVideo-%d.mov",arc4random() % 1000]];
NSURL *url = [NSURL fileURLWithPath:myPathDocs];

//Begin slow mo video export
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetHighestQuality];
exporter.outputURL = url;
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.shouldOptimizeForNetworkUse = YES;

[exporter exportAsynchronouslyWithCompletionHandler:^{
    dispatch_async(dispatch_get_main_queue(), ^{
        if (exporter.status == AVAssetExportSessionStatusCompleted) {
            NSURL *URL = exporter.outputURL;
            NSData *videoData = [NSData dataWithContentsOfURL:URL];

             // Upload
             [self uploadSelectedVideo:video data:videoData];
         }
    });
}];