IPhone : Video merging in background iOs

Task: Merge flyer image into flyer video.

Cases:

• Create a flyer[add emoticon image/text..etc]


• Create video

Case1

• Press back button[user will go to app listing of flyers screen], during this we are merging flyerSnapShoot in flyerVideo.and it works perfectly.


• Going to Phone Gallery we are seeing the updated video in it.

Case2

• Press iPhone Home button, I am doing things same as above but facing the following error.

FAIL = Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo=0x17266d40 {NSLocalizedDescription=The operation could not be completed, NSUnderlyingError=0x172b3920 "The operation couldn’t be completed. (OSStatus error -16980.)", NSLocalizedFailureReason=An unknown error occurred (-16980)}

Code:

- (void)modifyVideo:(NSURL *)src destination:(NSURL *)dest crop:(CGRect)crop
              scale:(CGFloat)scale overlay:(UIImage *)image
         completion:(void (^)(NSInteger, NSError *))callback {

    // Get a pointer to the asset
    AVURLAsset* firstAsset = [AVURLAsset URLAssetWithURL:src options:nil];

    // Make an instance of avmutablecomposition so that we can edit this asset:
    AVMutableComposition* mixComposition = [AVMutableComposition composition];

    // Add tracks to this composition
    AVMutableCompositionTrack *videoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];

    // Audio track
    AVMutableCompositionTrack *audioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

    // Image video is always 30 seconds. So we use that unless the background video is smaller.
    CMTime inTime = CMTimeMake( MAX_VIDEO_LENGTH * VIDEOFRAME, VIDEOFRAME );
    if ( CMTimeCompare( firstAsset.duration, inTime ) < 0 ) {
        inTime = firstAsset.duration;
    }

    // Add to the video track.
    NSArray *videos = [firstAsset tracksWithMediaType:AVMediaTypeVideo];
    CGAffineTransform transform;
    if ( videos.count > 0 ) {
        AVAssetTrack *track = [videos objectAtIndex:0];
        [videoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, inTime) ofTrack:track atTime:kCMTimeZero error:nil];
        transform = track.preferredTransform;
        videoTrack.preferredTransform = transform;
    }

    // Add the audio track.
    NSArray *audios = [firstAsset tracksWithMediaType:AVMediaTypeAudio];
    if ( audios.count > 0 ) {
        [audioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, inTime) ofTrack:[audios objectAtIndex:0] atTime:kCMTimeZero error:nil];
    }

    NSLog(@"Natural size: %.2f x %.2f", videoTrack.naturalSize.width, videoTrack.naturalSize.height);

    // Set the mix composition size.
    mixComposition.naturalSize = crop.size;

    // Set up the composition parameters.
    AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition];
    videoComposition.frameDuration = CMTimeMake(1, VIDEOFRAME );
    videoComposition.renderSize = crop.size;
    videoComposition.renderScale = 1.0;

    // Pass through parameters for animation.
    AVMutableVideoCompositionInstruction *passThroughInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
    passThroughInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, inTime);

    // Layer instructions
    AVMutableVideoCompositionLayerInstruction *passThroughLayer = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];

    // Set the transform to maintain orientation
    if ( scale != 1.0 ) {
        CGAffineTransform scaleTransform = CGAffineTransformMakeScale( scale, scale);
        CGAffineTransform translateTransform = CGAffineTransformTranslate( CGAffineTransformIdentity,
                                                                          -crop.origin.x,
                                                                          -crop.origin.y);
        transform = CGAffineTransformConcat( transform, scaleTransform );
        transform = CGAffineTransformConcat( transform, translateTransform);
    }

    [passThroughLayer setTransform:transform atTime:kCMTimeZero];

    passThroughInstruction.layerInstructions = @[ passThroughLayer ];
    videoComposition.instructions = @[passThroughInstruction];

    // If an image is given, then put that in the animation.
    if ( image != nil ) {

        // Layer that merges the video and image
        CALayer *parentLayer = [CALayer layer];
        parentLayer.frame = CGRectMake( 0, 0, crop.size.width, crop.size.height);

        // Layer that renders the video.
        CALayer *videoLayer = [CALayer layer];
        videoLayer.frame = CGRectMake(0, 0, crop.size.width, crop.size.height );
        [parentLayer addSublayer:videoLayer];

        // Layer that renders flyerly image.
        CALayer *imageLayer = [CALayer layer];
        imageLayer.frame = CGRectMake(0, 0, crop.size.width, crop.size.height );
        imageLayer.contents = (id)image.CGImage;
        [imageLayer setMasksToBounds:YES];

        [parentLayer addSublayer:imageLayer];

        // Setup the animation tool
        videoComposition.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];
    }

    // Now export the movie
    AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];
    exportSession.videoComposition = videoComposition;

    // Export the URL
    exportSession.outputURL = dest;
    exportSession.outputFileType = AVFileTypeQuickTimeMovie;
    exportSession.shouldOptimizeForNetworkUse = YES;
    [exportSession exportAsynchronouslyWithCompletionHandler:^{
        callback( exportSession.status, exportSession.error );
    }];
}

I am calling this function from AppDelegate.m

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    bgTask = [application beginBackgroundTaskWithName:@"MyTask" expirationHandler:^{
        // Clean up any unfinished task business by marking where you
        // stopped or ending the task outright.
        [application endBackgroundTask:bgTask];
        bgTask = UIBackgroundTaskInvalid;
    }];

    // Start the long-running task and return immediately.
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

        // Do the work associated with the task, preferably in chunks.
         [self goingToBg];

        [application endBackgroundTask:bgTask];
        bgTask = UIBackgroundTaskInvalid;
    });

    NSLog(@"backgroundTimeRemaining: %f", [[UIApplication sharedApplication] backgroundTimeRemaining]);
}