merging videos together (AVFoundation)

Question

In my app, I\'m recording small videos and adding them into an NSMutableArray as AVAsset so that i keep record of what has been captured. when the user

Answer 1

This will work fine

      AVMutableComposition *mainComposition = [[AVMutableComposition alloc] init];
      AVMutableCompositionTrack *compositionVideoTrack = [mainComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];


      AVMutableCompositionTrack *soundtrackTrack = [mainComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
      CMTime insertTime = kCMTimeZero;

      for (AVAsset *videoAsset in assets) {

          [compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:insertTime error:nil];

          [soundtrackTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:insertTime error:nil];

          // Updating the insertTime for the next insert
          insertTime = CMTimeAdd(insertTime, videoAsset.duration);
      }

      NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
      NSString *documentsDirectory = [paths objectAtIndex:0];

      // Creating a full path and URL to the exported video
      NSString *outputVideoPath =  [documentsDirectory stringByAppendingPathComponent:
                              [NSString stringWithFormat:@"mergeVideo-%d.mov",arc4random() % 1000]];

      // NSString *documentsDirectory = [paths objectAtIndex:0];
      NSString *myPathDocs =  [documentsDirectory stringByAppendingPathComponent:
                         current_name];
      NSURL *outptVideoUrl = [NSURL fileURLWithPath:myPathDocs];
      AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mainComposition presetName:AVAssetExportPreset640x480];

      // Setting attributes of the exporter
      exporter.outputURL=outptVideoUrl;
      exporter.outputFileType =AVFileTypeMPEG4;   //AVFileTypeQuickTimeMovie;
      exporter.shouldOptimizeForNetworkUse = YES;
      [exporter exportAsynchronouslyWithCompletionHandler:^{
          dispatch_async(dispatch_get_main_queue(), ^{
              //completion(exporter);
              [self exportDidFinish:exporter];
              // [self exportDidFinish:exporter:assets];
          });
      }];

this will work fine..