AVFoundation video playback issue

I've followed along with this excellent tutorial from Yuma and have something working. Below is the code that I'm using in my viewcontroller

import UIKit
import SceneKit
import ARKit
import AVFoundation
import SpriteKit

class ViewController: UIViewController, ARSCNViewDelegate {

    @IBOutlet var sceneView: ARSCNView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Set the view's delegate
        sceneView.delegate = self

        // Show statistics such as fps and timing information
        sceneView.showsStatistics = true

        // Create a new scene
        let scene = SCNScene(named: "art.scnassets/notebook.scn")!

        // Set the scene to the view
        sceneView.scene = scene
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        // Create a session configuration
        let configuration = ARImageTrackingConfiguration()

        guard let arImages = ARReferenceImage.referenceImages(inGroupNamed: "AR Resources", bundle: nil) else { return }
        configuration.trackingImages = arImages
        // Run the view's session
        sceneView.session.run(configuration)
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)

        // Pause the view's session
        sceneView.session.pause()
    }
    func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
        guard anchor is ARImageAnchor else { return }

        // Amy Image recognition
        guard let amyContainer = sceneView.scene.rootNode.childNode(withName: "amy", recursively: false) else { return }
        amyContainer.removeFromParentNode()
        node.addChildNode(amyContainer)
        amyContainer.isHidden = false

        // Video
        let videoURL = Bundle.main.url(forResource: "video", withExtension: "mp4")!

        let videoPlayer = AVPlayer(url: videoURL)

        let videoScene = SKScene(size: CGSize(width: 900.0, height: 1400.0))

        let videoNode = SKVideoNode(avPlayer: videoPlayer)

        videoNode.position = CGPoint(x: videoScene.size.width / 2, y: videoScene.size.height / 2)

        videoNode.size = videoScene.size

        videoNode.yScale = -1

        videoNode.play()

        videoScene.addChild(videoNode)

        guard let video = amyContainer.childNode(withName: "video", recursively: true)
        else { return }
    video.geometry?.firstMaterial?.diffuse.contents = videoScene

 }
 }

When I use the video that was supplied as part of the tutorial everything works perfectly, but when I try and include a video that I've created I only get a white box over the target image, but no video.

I've tripled checked the name, I've tried to export the video with the exact same dimensions all with no luck. I've tested uploading a new version of the video that does work as a different file name and changed the names and it works, so I have to assume it's the .mp4 that I'm producing which is the problem.

Are there particular rules/settings that are required for mp4's for this kind of approach, is there a setting in premiere pro or Handbrake that I can use? Or how can I debug any internal errors that are happening through Xcode itself?

from AVFoundation video playback issue