NDISenderExample

Overview

Minimum implementation of the NDI SDK that works on the iPhone using Swift, with a set of exposed API to control the camera:

• List all available cameras GET /cameras
• Get active camera GET /cameras/active
• Switch camera POST /cameras/select
• Zoom with the selected camera POST /camera/zoom
• Change exposure bias POST /camera/exposure/bias
• Enable auto white balance GET /camera/white-balance/mode/auto
• Enable custom white balance GET /camera/white-balance/mode/locked
• Get current white balance temperature and white balance tint GET /camera/white-balance/temp-tint
• Set a new white balance temperature and white balance tint POST /camera/white-balance/temp-tint
• Set a custom white balance with a grey reference colour card GET /camera/white-balance/grey
• Hide controls on screen GET /controls/hide
• Show controls on screen GET /controls/show
• Start NDI GET /ndi/start
• Stop NDI GET /ndi/stop
• Change session preset between 1080p, 720p and 4K with GET /preset/1080p, GET /preset/720p and GET /preset/4K respectively
• Get current microphone GET /audio/inputs/current
• Change current microphone POST /audio/inputs/current
• Get all available microphones GET /audio/inputs
• Get all available audio outputs GET /audio/outputs
• Get current audio output GET /audio/outputs/current
• Start recording GET /recording/start
• Stop recording GET /recording/stop

POST requests require a body of type application/x-www-form-urlencoded. As of Mar/2021, I haven't made a Swagger file for all the endpoints yet. To see what parameters you need to input, have a look at NDIControls.swift. For example, to change the white balance temperature and tint, you will need temperature and tint keys in the POST body, as indicated by the code in NDIControls.swift as below:

webServer.addHandler(forMethod: "POST", pathRegex: "/camera/white-balance/temp-tint", request: GCDWebServerURLEncodedFormRequest.self) { [unowned self] (request) -> GCDWebServerResponse? in
   let r = request as! GCDWebServerURLEncodedFormRequest
   guard let temp = Float(r.arguments["temperature"] ?? "invalidNumber"),
         let tint = Float(r.arguments["tint"] ?? "invalidNumber")

How it works

When the app first starts, it will start the web server on port 80. If the phone is connected to a LAN network, the user can access this endpoint using http://<PHONE_LAN_HOST>. Here, a basic and lagging UI (in terms of development in relations to the APIs exposed) is available. To use the APIs directly, you can enter in http://<PHONE_LAN_HOST>/cameras to get all the cameras available on the phone. A link to the controls will be shown on the screen and will also be shown in Xcode's Output window if you're building the project.

To download a recording, navigate to http://<PHONE_LAN_HOST>.

The app is built with the assumption that Metalkit effects will be added in the future (chroma-key, filters, etc.). In CameraViewController.swift, you can find a similar block as below

cameraCapture = CameraCapture(cameraPosition: .back, processingCallback: { [unowned self] (image) in
   guard let image = image else { return }

   // isUsingFilters defined before viewDidLoad()
   if self.isUsingFilters {
      // You can use CIFilters here.
      let filter = CIFilter.colorMonochrome()
      filter.intensity = 1
      filter.color = CIColor(red: 0.5, green: 0.5, blue: 0.5)
      filter.inputImage = image
      guard let output = filter.outputImage else { return }
      self.metalView.image = output
      NDIControls.instance.send(image: output)
   } else {
      self.metalView.image = image
      NDIControls.instance.send(image: image)
   }
})

In this block, you can chain CIFilters and build some cool effects.

You'll need a high-speed network connection and an Apple device capable of MetalKit 2.

How to build

1. Get the SDK from the NDI SDK site and install it (using 5.0 as of Nov/2021).
2. Copy module.map into /Library/NDI Advanced SDK for Apple/include.
3. Open the top-level NDISenderExample.xcworkspace in Xcode, select the NDISenderExample schema, and run it. The project expects to find libndi_ios.a in /Library/NDI Advanced SDK for Apple/lib/iOS/libndi_ios.a.
4. Tap the Send button on the screen to start sending with NDI.

Help out

Check the issues list for known issues.

Acknowledgement

Base NDI bridge based on satoshi0212's example.