NDI and Spout can both move live visual content between applications, but they are designed for different environments. The simplest rule is: Spout is usually the better choice between compatible applications on the same Windows computer; NDI is usually the better choice when video needs to travel across a network or between different machines.
- Use Spout for local GPU-to-GPU sharing between compatible Windows applications.
- Use NDI when the source and projection mapper are on different computers or the video must travel over a LAN.
- Use imported media instead of either protocol when the content is a fixed file and does not need to be live.
What is Spout?
Spout is a Windows-oriented texture-sharing ecosystem used by many visual applications. Instead of encoding a video stream and sending it through a normal network path, compatible applications can share rendered frames locally. That makes it useful for chaining tools together on one production PC.
A common setup is:
Visual generator / VJ app → Spout → HoloMapper → projector
The source application focuses on generating the image while HoloMapper handles the physical surface alignment.
What is NDI?
NDI is designed for IP video workflows. A compatible sender publishes video over a network and a compatible receiver can subscribe to it. This is useful when the source is another computer, a production system elsewhere in the venue, or an application that already outputs NDI.
A common setup is:
Camera or graphics computer → Ethernet network → NDI → HoloMapper → projector
NDI vs Spout comparison
| Question | Spout | NDI |
|---|---|---|
| Same PC? | Excellent fit | Possible, but often unnecessary |
| Different computers? | No normal LAN transport | Designed for network workflows |
| Windows ecosystem? | Strong | Cross-platform ecosystem varies by app |
| Network bandwidth required? | No LAN stream | Yes |
| Best use | Local app-to-app visuals | Network cameras/graphics/remote machines |
When Spout is the better projection mapping workflow
Use Spout when a Windows machine is already running both the content application and HoloMapper. Examples include sending visuals from a VJ tool, a shader/generative program, a game engine, or another graphics application into a mapped surface without rendering an intermediate video file.
It also keeps your network out of the critical path, which can simplify troubleshooting during a live show.
When NDI is the better projection mapping workflow
Use NDI when the source is physically or logically separate from the mapper. A venue might have one computer handling cameras and graphics while another computer drives the projector. NDI lets the systems communicate over the existing network rather than requiring a dedicated capture-card path for every feed.
For reliable live use, wired Ethernet is strongly preferable to congested Wi-Fi.
Can HoloMapper use both?
Yes. HoloMapper currently supports NDI input/output and Spout input/output workflows, alongside ordinary images, videos, GIFs, text, animation presets, and other mapped layer types. That means you can choose the transport based on where the source lives instead of changing your mapping workflow.
Practical recommendation
If everything is on one Windows PC, test Spout first. If the source is on another computer, test NDI over wired Ethernet first. If the media never changes, do not add a live-video protocol at all—import the file directly and remove an unnecessary point of failure.
