Unire video clip in un singolo video come Vine

Question

Vorrei utilizzare uno UIImagePickerController per registrare più video clip e quindi unirli in un unico video, in modo simile a come l'app Vine lo fa. Qualcuno può indicarmi la giusta direzione su come combinare i video clip in un singolo video?

Answer 1

Il sito di Ray Wenderlich ha un tutorial che copre questo. http://www.raywenderlich.com/13418/how-to-play-record-edit-videos-in-ios

Answer 2

Ecco un esempio di come unirei video, parzialmente basati sul blog di Ray Wenderlich.

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info 
{ 
    [appDelegate.playerLayer removeFromSuperlayer]; 

    if (self.firstAsset) 
    { 
    self.secondAssetURL = [info objectForKey:UIImagePickerControllerMediaURL]; 
    self.secondAsset = [AVAsset assetWithURL:self.secondAssetURL]; 
    } 
    else 
    { 
    self.firstAssetURL = [info objectForKey:UIImagePickerControllerMediaURL]; 
    self.firstAsset = [AVAsset assetWithURL:self.firstAssetURL]; 
    } 

    if (self.secondAsset) 
    { 
    CMTime recordTime = CMTimeMakeWithSeconds(self.recordTime, NSEC_PER_SEC); 
    AVMutableComposition *mixComposition = [AVMutableComposition new]; 

    AVMutableCompositionTrack *videoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid]; 
    [videoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, self.firstAsset.duration) ofTrack:[[self.firstAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:kCMTimeZero error:nil]; 
    [videoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, self.secondAsset.duration) 
         ofTrack:[[self.secondAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:recordTime error:nil]; 

    AVURLAsset *firstAudioAsset = [[AVURLAsset alloc] initWithURL:self.firstAssetURL options:nil]; 
    AVURLAsset *secondAudioAsset = [[AVURLAsset alloc] initWithURL:self.secondAssetURL options:nil]; 

    AVAssetTrack *firstAudioTrack = [[firstAudioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0]; 
    AVAssetTrack *secondAudioTrack = [[secondAudioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0]; 

    AVMutableCompositionTrack *compositionAudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid]; 
    [compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, firstAudioAsset.duration) ofTrack:firstAudioTrack atTime:kCMTimeZero error:nil]; 
    [compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, secondAudioAsset.duration) ofTrack:secondAudioTrack atTime:recordTime error:nil]; 

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentsDirectory = [paths objectAtIndex:0]; 
    NSString *myPathDocs = [documentsDirectory stringByAppendingPathComponent: 
          [NSString stringWithFormat:@"mergeVideo-%d.mov",arc4random() % 1000]]; 
    NSURL *url = [NSURL fileURLWithPath:myPathDocs]; 
    // 5 - Create exporter 
    AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition 
                     presetName:AVAssetExportPresetHighestQuality]; 
    exporter.outputURL=url; 
    exporter.outputFileType = AVFileTypeQuickTimeMovie; 
    exporter.shouldOptimizeForNetworkUse = YES; 
    [exporter exportAsynchronouslyWithCompletionHandler:^{ 
     NSLog(@"we are now exporting"); 
     int exportStatus = exporter.status; 
     switch (exportStatus) { 
     case AVAssetExportSessionStatusFailed: { 
      // log error to text view 
      NSError *exportError = exporter.error; 
      NSLog (@"AVAssetExportSessionStatusFailed: %@", exportError); 
      break; 
     } 
     case AVAssetExportSessionStatusCompleted: { 
      NSLog (@"AVAssetExportSessionStatusCompleted"); 
      self.firstAssetURL = exporter.outputURL; 
      self.firstAsset = [AVAsset assetWithURL:self.firstAssetURL]; 
      dispatch_async(dispatch_get_main_queue(), ^{ 
      [self layoutVideo:exporter.outputURL]; 
      }); 
      break; 
     } 
     default: { NSLog (@"didn't get export status"); break;} 
     } 

    }]; 
    } 
    else 
    { 
    [self layoutVideo:[info objectForKey:@"UIImagePickerControllerMediaURL"]]; 
    } 

}