Crash When Exporting Video with Text Overlay

• Currently, we only see this crash in the simulator.

  • We're not yet seeing it on devices.

• So far we've duplicated the crash with the iOS 13.5 simulator and iOS 13.6 simulator.

  • The crash doesn't seem to happen in the iOS 13.0 simulator.

  • We haven't yet tested other simulator SDK's.

Code Block Thread 71 Queue : com.apple.coremedia.basicvideocompositor.output (serial)#0	0x00007fff522fe133 in _xpc_api_misuse ()#1	0x00007fff522f855d in _xpc_shmem_create_with_prot ()#2	0x00007fff260d03ec in _ioSurfaceClientCreate ()#3	0x00007fff260cc3ac in -[IOSurface initWithProperties:] ()#4	0x00007fff2b3b3e6f in CA::Render::Image::retain_iosurface() const ()#5	0x00007fff2b401984 in CA::OGL::GLESContext::retain_image(CA::OGL::Image*, CA::Render::Texture*, bool) ()#6	0x00007fff2b3ff780 in CA::OGL::GLESContext::bind_image_impl(unsigned int, CA::Render::Texture*, unsigned int, CA::OGL::TextureFilter, CA::OGL::TextureFilter, float, CA::OGL::TextureEdgeMode, float*, char const*) ()#7	0x00007fff2b4059e6 in CA::OGL::Context::bind_image(unsigned int, CA::Render::Texture*, unsigned int, CA::OGL::TextureFilter, CA::OGL::TextureFilter, float, CA::OGL::TextureEdgeMode, CA::OGL::ContentsGeometry const*, float*, char const*) ()#8	0x00007fff2b3eaff0 in CA::OGL::render_contents_background(CA::OGL::Renderer&, CA::OGL::Layer const*) ()#9	0x00007fff2b4c187b in CA::OGL::LayerNode::apply(float, CA::OGL::Surface**, float*) ()#10	0x00007fff2b4bf5d7 in CA::OGL::ImagingNode::render(CA::OGL::ImagingNode::RenderClosure*, unsigned int) ()#11	0x00007fff2b3f01b9 in CA::OGL::render_layers(CA::OGL::Renderer&, CA::OGL::Layer*) ()#12	0x00007fff2b4c191f in CA::OGL::LayerNode::apply(float, CA::OGL::Surface**, float*) ()#13	0x00007fff2b4bf5d7 in CA::OGL::ImagingNode::render(CA::OGL::ImagingNode::RenderClosure*, unsigned int) ()#14	0x00007fff2b3f01b9 in CA::OGL::render_layers(CA::OGL::Renderer&, CA::OGL::Layer*) ()#15	0x00007fff2b4c191f in CA::OGL::LayerNode::apply(float, CA::OGL::Surface**, float*) ()#16	0x00007fff2b4bf5d7 in CA::OGL::ImagingNode::render(CA::OGL::ImagingNode::RenderClosure*, unsigned int) ()#17	0x00007fff2b3f01b9 in CA::OGL::render_layers(CA::OGL::Renderer&, CA::OGL::Layer*) ()#18	0x00007fff2b3f0999 in CA::OGL::render_root_layers(CA::OGL::Renderer&, x_link_struct const*, CA::OGL::Gstate const&) ()#19	0x00007fff2b3c4866 in CA::OGL::Renderer::render(CA::Render::Update const*, unsigned long) ()#20	0x00007fff2b3c7383 in CA::OGL::render(CA::OGL::Renderer&, CA::Render::Update*, unsigned long) ()#21	0x00007fff2b58e2c9 in -[CARenderer render] ()#22	0x00007fff280e2b9d in FigCoreAnimationRendererCopyPixelBufferAtTime ()#23	0x00007fff27ff1d5e in FigVCPCoreAnimationPostProcessorCopyPixelBufferAtTime ()#24	0x00007fff2807f3ee in videoprocessor_frameCompleteCallback ()#25	0x00007fff27ff3bda in fvcp_compositorHost_FrameCompletion ()#26	0x00007fff28087b4a in __basicVideoCompositor_RenderFrame_block_invoke_2 ()#27	0x00000001079c0f11 in _dispatch_call_block_and_release ()#28	0x00000001079c1e8e in _dispatch_client_callout ()#29	0x00000001079c86fd in _dispatch_lane_serial_drain ()#30	0x00000001079c92c5 in _dispatch_lane_invoke ()#31	0x00000001079d3399 in _dispatch_root_queue_drain ()#32	0x00000001079d3168 in _dispatch_worker_thread ()#33	0x00007fff522b7109 in _pthread_start ()#34	0x00007fff522b2b8b in thread_start ()Enqueued from com.apple.root.default-qos.overcommit (Thread 54) Queue : com.apple.root.default-qos.overcommit (serial)#0	0x00000001079c5d46 in dispatch_async ()#1	0x00007fff28085f85 in basicVideoCompositor_RenderFrame ()#2	0x00007fff27ff3a13 in FigVCPCompositorHostComposeFrameAsync ()#3	0x00007fff2807f08c in videoprocessor_processUntilHighWaterMet ()#4	0x00007fff27f7ecbe in activitySchedulerOnThread ()#5	0x00007fff24debe7a in figThreadMain ()#6	0x00007fff522b7109 in _pthread_start ()#7	0x00007fff522b2b8b in thread_start ()

Code Block libxpc.dylib`_xpc_api_misuse:  0x7fff522fe0b4 <+0>:  pushq %rbp  0x7fff522fe0b5 <+1>:  movq  %rsp, %rbp  0x7fff522fe0b8 <+4>:  pushq %rbx  0x7fff522fe0b9 <+5>:  subq  $0xa8, %rsp  0x7fff522fe0c0 <+12>: movq  %rdi, %r9  0x7fff522fe0c3 <+15>: movaps 0xdc06(%rip), %xmm0    ; xpcVersionNumber + 160  0x7fff522fe0ca <+22>: leaq  -0xb0(%rbp), %rbx  0x7fff522fe0d1 <+29>: movaps %xmm0, 0x90(%rbx)  0x7fff522fe0d8 <+36>: movaps %xmm0, 0x80(%rbx)  0x7fff522fe0df <+43>: movaps %xmm0, 0x70(%rbx)  0x7fff522fe0e3 <+47>: movaps %xmm0, 0x60(%rbx)  0x7fff522fe0e7 <+51>: movaps %xmm0, 0x50(%rbx)  0x7fff522fe0eb <+55>: movaps %xmm0, 0x40(%rbx)  0x7fff522fe0ef <+59>: movaps %xmm0, 0x30(%rbx)  0x7fff522fe0f3 <+63>: movaps %xmm0, 0x20(%rbx)  0x7fff522fe0f7 <+67>: movaps %xmm0, 0x10(%rbx)  0x7fff522fe0fb <+71>: movaps %xmm0, (%rbx)  0x7fff522fe0fe <+74>: leaq  0x115ad(%rip), %r8    ; "XPC API Misuse: %s"  0x7fff522fe105 <+81>: movl  $0xa0, %esi  0x7fff522fe10a <+86>: movl  $0xa0, %ecx  0x7fff522fe10f <+91>: movq  %rbx, %rdi  0x7fff522fe112 <+94>: movl  $0x0, %edx  0x7fff522fe117 <+99>: xorl  %eax, %eax  0x7fff522fe119 <+101>: callq 0x7fff5230add8      ; symbol stub for: snprintf_chk  0x7fff522fe11e <+106>: movq  %rbx, 0x37abe863(%rip)  ; gCRAnnotations + 8  0x7fff522fe125 <+113>: leaq  0x11599(%rip), %rax    ; "API Misuse"  0x7fff522fe12c <+120>: movq  %rax, 0x37abe85d(%rip)  ; gCRAnnotations + 16-> 0x7fff522fe133 <+127>: ud2   

Meet same issues, but on Simulator (Xcode 12.4 (12D4e)) only.

After some research, I found this crash is lead by AVVideoCompositionCoreAnimationTool's

+videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:inLayer:

And I fixed it by replacing it w/ one below (but need to handle instruction.layerInstructions in this way):

+videoCompositionCoreAnimationToolWithAdditionalLayer:asTrackID:

Below is a sample Objective-C code works on both real device & simulator:

...
 
// Prepare watermark layer
CALayer *watermarkLayer = ...;
CMPersistentTrackID watermarkLayerTrackID = [asset unusedTrackID];
// !!! NOTE#01: Use as additional layer here instead of animation layer.
videoComposition.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithAdditionalLayer:watermarkLayer asTrackID:watermarkLayerTrackID];
      
// Create video composition instruction
AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, asset.duration);
 
// - Watermark layer instruction
// !!! NOTE#02: Make this instruction track watermark layer by the `trackID`.
AVMutableVideoCompositionLayerInstruction *watermarkLayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstruction];
watermarkLayerInstruction.trackID = watermarkLayerTrackID;
 
// - Video track layer instruction
AVAssetTrack *videoTrack = [asset tracksWithMediaType:AVMediaTypeVideo].firstObject;
AVMutableVideoCompositionLayerInstruction *videoLayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
    
// Watermark layer above video layer here.
instruction.layerInstructions = @[
  watermarkLayerInstruction,
  videoLayerInstruction,
];
      
videoComposition.instructions = @[instruction];
 
// Export the video w/ watermark.
AVAssetExportSession *exportSession = ...;
...
exportSession.videoComposition = videoComposition;
 
...

And btw, if you just need to add an image as watermark, another solution by using AVVideoComposition's

-videoCompositionWithAsset:applyingCIFiltersWithHandler:

also works well on both real device & simulator, but I tested it and found it's slower. Seems this way is more suitable for video blender/filter.

Just started seeing this today on Xcode 13 on Simulator, and tested on iOS 15 and 14.5 (both on Simulator). Cannot reproduce on device. This is super frustrating. Anyone have a solve for it yet.

Thanks @Kjuly

here is a Swift implementation based on your answer

 func merge(video videoPath: String, withForegroundImage foregroundImage: UIImage, completion: @escaping (URL?) -> Void) -> () {
 
        let videoUrl = URL(fileURLWithPath: videoPath)
 
        let videoUrlAsset = AVAsset(url: videoUrl)
 
        
 
        guard let videoTrack = videoUrlAsset.tracks(withMediaType: .video).first else { return }
 
        
 
        // Prepare watermark layer
 
        let imageLayer = CALayer()
 
        imageLayer.contents = foregroundImage.cgImage
 
        imageLayer.frame = CGRect(x: videoTrack.naturalSize.width - 300, y: 0.0, width: 300, height: 300)
 
        let unusedTrackID = videoUrlAsset.unusedTrackID()
 
        // !!! NOTE#01: Use as additional layer here instead of animation layer.
 
        let videoComposition = AVMutableVideoComposition(propertiesOf: videoUrlAsset)
 
        videoComposition.animationTool = AVVideoCompositionCoreAnimationTool(additionalLayer: imageLayer, asTrackID: unusedTrackID)
 
        // Create video composition instruction
 
        let mutableInstrucitons = AVMutableVideoCompositionInstruction()
 
        mutableInstrucitons.timeRange = CMTimeRange(start: .zero, duration: videoUrlAsset.duration)
 
        // - Watermark layer instruction
 
        // !!! NOTE#02: Make this instruction track watermark layer by the `trackID`.
 
        let mutableLayerInstruction = AVMutableVideoCompositionLayerInstruction()
 
        mutableLayerInstruction.trackID = unusedTrackID
 
        // - Video track layer instruction
 
        let mutableVideoCompostionLayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: videoTrack)
 
        // Watermark layer above video layer here.
 
        mutableInstrucitons.layerInstructions = [mutableLayerInstruction, mutableVideoCompostionLayerInstruction]
 
        videoComposition.instructions = [mutableInstrucitons]
 
        // Export to file
 
        let path = NSTemporaryDirectory().appending("mergedVideo.mp4")
 
        let destinationFilePath = URL.init(fileURLWithPath: path)
 
        do {
 
            if FileManager.default.fileExists(atPath: destinationFilePath.path) {
 
                try FileManager.default.removeItem(at: destinationFilePath)
 
                print("removed")
 
            }
 
        } catch {
 
            print(error)
 
        }
 
        let exportSession = AVAssetExportSession( asset: videoUrlAsset, presetName: AVAssetExportPresetHighestQuality)!
 
        exportSession.videoComposition = videoComposition
 
        exportSession.outputURL = destinationFilePath
 
        exportSession.outputFileType = AVFileType.mp4
 
        exportSession.exportAsynchronously { [weak exportSession] in
 
            if let strongExportSession = exportSession {
 
                completion(strongExportSession.outputURL!)
 
            }
 
        }
 
    }
 
}

I've intermittently had the same issue of the years depending on which iOS version apple put out. The issue "seemed" to go away in iOS 15.7 but in iOS 16+ it is intermittently back. I filled a feedback request with Apple with sample project, steps to reproduce, and video leading up to hang then crash. Fingers crossed that they finally fix this issue.

UPDATE: Also happens in 16.2 Beta (Oct 25, 2022) on all of my devices including iPhone 14 Pro Max.

Still same issues on iOS 16.2 simulator. The issue is with videoComposition. If I removed composition from AVAssetExportSession, it works.

Still the same error on iOS 17.0 simulator. When i make the layer fully opaque it works, but as soon as the layer has a slightly transparent element, it crashes with the same error.