video合并在后台iOS

任务：将传单图像合并为传单video。

案例 ：

• 创build一个传单[添加表情图像/文本..等]
• 创buildvideo

情况1

• 按下返回button[用户将转到传单屏幕的应用程序列表]，在此期间，我们正在flyerVideo中合并flyerSnapShoot，并且完美地工作 。
• 去电话画廊，我们看到了更新的video。

案例2

• 按iPhone的主页button，我正在做同样的事情，但面临以下错误 。

FAIL = Error Domain = AVFoundationErrorDomain Code = -11800“操作无法完成”UserInfo = 0x17266d40 {NSLocalizedDescription =操作无法完成，NSUnderlyingError = 0x172b3920“操作无法完成（OSStatus错误-16980。） “，NSLocalizedFailureReason =发生未知错误（-16980）}

代码 ：

- (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 ); }]; } 

我从AppDelegate.m调用这个函数

 - (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]); } 

Answer 1

在这个问题上做了很多RND，没有find解决scheme。

希望分享几个链接，希望它能帮助栈社区，如果他们在同一个问题[要求]。

Link1： AVExportSession在后台运行

引用相关的问题[从上面复制Link1]

不幸的是，由于AVAssetExportSession使用gpu来完成它的一些工作，所以如果你使用AVVideoComposition，它不能在后台运行。

链接2： 在后台启动AVAssetExportSession

引用相关的问题[从上面复制Link2]

您可以在后台启动AVAssetExportSession。 AVFoundation在后台执行工作的唯一限制是使用AVVideoCompositions或AVMutableVideoCompositions。 AVVideoCompositions正在使用GPU，并且GPU不能在后台使用

url（用于后台任务）：

APPLE DEV URL

RAYWENDERLICHurl

堆栈的问题

Answer 2

如果在项目的function中更新您的“背景模式”设置以包含audio，那么晚会太晚了。 这将允许出口。

这是为了在后台播放音乐。

这个对我有用。