Spout Input

Spout is a Windows-native GPU texture-sharing framework that lets any Spout-capable application share its rendered output directly as a live video source in Exaplay 3 — with zero latency and zero compression, because the texture never leaves the GPU.

What Is Spout?

Spout (developed by Lynn Jarvis) enables real-time sharing of OpenGL textures between applications on the same Windows PC. Popular Spout senders include:

Application	Use case
Resolume Avenue / Arena	VJ software sending to Exaplay for output
TouchDesigner	Generative / interactive content
OBS Studio (with Spout plugin)	Streaming software output
Unity / Unreal Engine	Real-time 3D content
Processing	Creative coding

Because the texture lives on the GPU, Spout has effectively zero CPU overhead and zero latency — the frame appears in Exaplay the moment the sender renders it.

Adding a Spout Source

1. Open the File Browser → Live Feeds tab.
2. A generic Spout Input entry is always visible, even when no Spout sender is running. This allows preprogramming your show in advance.
3. Any currently active Spout senders also appear individually (e.g. Spout: MyApp).
4. Drag Spout Input (or a specific sender) onto a track in the Timeline.

Tip: Use the generic Spout Input when preprogramming — it connects to whatever sender becomes active later. Use a named sender entry when you need a specific source.

Note: Spout requires SpoutLibrary.dll, which is included in the Exaplay installation. No separate SDK install is needed.

Selecting a Sender

If multiple Spout senders are active, each appears with its sender name as a separate item in the Live Feeds list. The sender name is set by the originating application.

To switch a running Spout clip to a different sender:

1. Select the Spout clip in the Timeline.
2. In the Inspector, use the Spout Sender drop-down to choose a different active sender, or select Any Sender to connect to whatever is currently broadcasting.
3. The switch is hot — Exaplay seamlessly transitions to the new sender without interrupting playback.

Saving & Loading Spout Clips (VPP)

Spout clips are fully saved in VPP project files:

• The selected sender name (or "Any Sender" mode) is preserved.
• On project load, each Spout clip reconnects to its saved sender automatically.
• If the sender is not yet running, the clip waits and reconnects when the sender starts.

Behaviour When the Sender Disconnects

If the Spout sender stops or closes while Exaplay is using it:

• The output clears to black automatically.
• A warning is logged to the engine log (Documents\Exaplay3\logs\).
• When the sender restarts, Exaplay reconnects automatically without any user action.

Sender Size Changes

If the Spout sender changes its output resolution (e.g. a window resize), Exaplay detects the new dimensions on the next frame and resizes its internal texture buffer automatically. No manual reconfiguration is needed.

Performance

Metric	Typical value
Latency	< 1 frame (GPU direct)
CPU overhead	< 1 %
GPU overhead	~0.5 % (texture copy)
Maximum resolution	Limited by GPU VRAM

Comparison: Spout vs NDI vs Capture Card

Method	Latency	CPU	Cross-machine	Compression
Spout	< 1 frame	Minimal	❌ Same PC only	None (GPU texture)
NDI	1–3 frames	Moderate	✅ Network	Low (NDI codec)
Capture card	1–4 frames	Low	✅ HDMI	None (raw)

Use Spout when the source application runs on the same machine as Exaplay and you need the absolute lowest latency.

Identifying Spout Clips

Spout clips show a distinctive Spout icon (a waveform-style "S" logo) in:

• The File Browser Live Feeds tab
• Timeline segment thumbnails
• The Playlist composition view