视频编辑

1. 最近我们在做一个运动的app 里面用到视频编辑，给大家推荐一个仿抖音视频的demo
   [VideoSliderCrop]([https://github.com/1401788197/VideoSliderCrop]
   2.设计思路

底部是一个视频播放器 SJVideoPlayView

播放器上面试一个视频裁剪视图 SJVideoCropView

里面包含一个 UICollectionView 用来加载视频缩略图 左右滑块以及进度条

拖动左右滑块、进度条、以及CollectionView的时候，实时把当前进度传递给视频播放器、视频播放器跳转

1、调节视频进度

[self.palyView.player seekToTime:CMTimeMake(time * 1000, 1000) toleranceBefore:kCMTimeZero toleranceAfter:kCMTimeZero];

2、获取进度条位置

#pragma mark  手指滑动截取视频
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    if (!_imageViewSelected) return;
//   locationInView:获取到的是手指点击屏幕实时的坐标点；

//translationInView：获取到的是手指移动后，在相对坐标中的偏移量
//previousLocationInView:是获得前一个坐标。
    UITouch *touch = (UITouch *)[touches anyObject];
    CGPoint lp = [touch locationInView:_collectionView];
    CGPoint pp = [touch previousLocationInView:_collectionView];
}

3、手势判断

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    _imageViewSelected = nil;
    if ([_delegate respondsToSelector:@selector(cutBarTouchesDidEnd)]) {
        [_delegate cutBarTouchesDidEnd];
    }
}

#pragma mark  手指滑动截取视频
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event

4、视频取帧

  #pragma mark  加载视频截图
- (void)loadThumbnailData {
//    _durationLaber.text=[NSString stringWithFormat:@"已选取%@s",[NSString stringWithFormat:@"%.0f",_mediaConfig.endTime - _mediaConfig.startTime]];
    _selectTime =_mediaConfig.endTime - _mediaConfig.startTime;
    CMTime startTime = kCMTimeZero;
    NSMutableArray *array = [NSMutableArray array];
    CMTime addTime = CMTimeMake(1000,1000);
    CGFloat d = _mediaConfig.sourceDuration / (_itemCount-1);
    int intd = d * 100;
    float fd = intd / 100.0;
    addTime = CMTimeMakeWithSeconds(fd, 1000);
    
    CMTime endTime = CMTimeMakeWithSeconds(_mediaConfig.sourceDuration, 1000);
    
    while (CMTIME_COMPARE_INLINE(startTime, <=, endTime)) {
        [array addObject:[NSValue valueWithCMTime:startTime]];
        startTime = CMTimeAdd(startTime, addTime);
    }
    
    // 第一帧取第0.1s   规避有些视频并不是从第0s开始的
    array[0] = [NSValue valueWithCMTime:CMTimeMakeWithSeconds(0.1, 1000)];
    __weak __typeof(self) weakSelf = self;
    __block int index = 0;
    [self.imageGenerator generateCGImagesAsynchronouslyForTimes:array completionHandler:^(CMTime requestedTime, CGImageRef  _Nullable image, CMTime actualTime, AVAssetImageGeneratorResult result, NSError * _Nullable error) {
        
        if (result == AVAssetImageGeneratorSucceeded) {
            UIImage *img = [[UIImage alloc] initWithCGImage:image];
            dispatch_sync(dispatch_get_main_queue(), ^{
                [weakSelf.imagesArray addObject:img];
                if (index==1) {
                    if (weakSelf.reImgBlock) {
                        weakSelf.reImgBlock(img);
                    }
                }
                
                NSIndexPath *indexPath = [NSIndexPath indexPathForItem:index inSection:0];
                [weakSelf.collectionView insertItemsAtIndexPaths:@[indexPath]];
                index++;
            });
        }
    }];
}

- (AVAssetImageGenerator *)imageGenerator {
    if (!_imageGenerator) {
        _imageGenerator = [[AVAssetImageGenerator alloc] initWithAsset:_avAsset];
        _imageGenerator.appliesPreferredTrackTransform = YES;
        _imageGenerator.requestedTimeToleranceBefore = kCMTimeZero;
        _imageGenerator.requestedTimeToleranceAfter = kCMTimeZero;
        _imageGenerator.maximumSize = CGSizeMake(320, 320);
    }
    return _imageGenerator;
}

5、视频截取保存

#pragma mark 视频裁剪
- (void)notifyDelegateOfDidChange:(BOOL)isUpload{
    
    
    NSString *timeStr = [StrTool getNowTimeTimestamp3];
    
    NSString *documents = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
    
    self.tempVideoPath = [documents stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.mp4",timeStr]];
    
    
//
    [BluetoothDataManager tailorBlueTooth:_blueToothFilePaths startTime:self.startTime endTime:self.endTime sumTime:self.videoSumTime];
    [self deleteTempFile:self.tempVideoPath];
 
    
    AVAsset *asset = [AVAsset assetWithURL:self.videoUrl];
    AVAssetExportSession *exportSession = [[AVAssetExportSession alloc]
                                           initWithAsset:asset presetName:AVAssetExportPresetPassthrough];
    NSURL *furl = [NSURL fileURLWithPath:self.tempVideoPath];
   
    exportSession.outputURL = furl;
    exportSession.outputFileType = AVFileTypeQuickTimeMovie;
    
    CMTime start = CMTimeMakeWithSeconds(self.startTime, self.player.currentTime.timescale);
    CMTime duration = CMTimeMakeWithSeconds(self.endTime - self.startTime, self.player.currentTime.timescale);;
    CMTimeRange range = CMTimeRangeMake(start, duration);
    exportSession.timeRange = range;
    
    [exportSession exportAsynchronouslyWithCompletionHandler:^{
        switch ([exportSession status]) {
            case AVAssetExportSessionStatusFailed:
                NSLog(@"Export failed: %@",[exportSession error]);
                break;
                
            case AVAssetExportSessionStatusCancelled:
                NSLog(@"Export canceled");
                break;
                
            case AVAssetExportSessionStatusCompleted:{
                NSLog(@"Export completed");
                __weak typeof(self) weakSelf = self;
                dispatch_async(dispatch_get_main_queue(), ^{
                    UISaveVideoAtPathToSavedPhotosAlbum([furl relativePath], self,@selector(video:didFinishSavingWithError:contextInfo:), nil);
                    NSLog(@"编辑后的视频路径： %@",weakSelf.tempVideoPath);
                    

//                  [weakSelf invalidatePlayer];
                  [self deleteTempFile:[self.videoUrl absoluteString]];
                    
                    self.videoUrl = [NSURL fileURLWithPath:self.tempVideoPath];
                    if (isUpload) {
                        [self VODUpload];
                    }else{
                        [self saveVideo];
                    }

                });
            }
                break;
                
            default:
                NSLog(@"Export other");
                
                break;
        }
    }];
    
   
}

- (void)video:(NSString*)videoPath didFinishSavingWithError:(NSError*)error contextInfo:(void*)contextInfo {
    if (error) {
        NSLog(@"保存到相册失败:%@",error);
    }
    else {
        NSLog(@"保存到相册成功");
    }
}

6、avplayer销毁

    self.palyView.playerStatus = CropPlayerStatusPause;
   [ self.palyView.player.currentItem cancelPendingSeeks];
  [ self.palyView.player.currentItem.asset cancelLoading]; 

     self.palyView.player = nil；