Video I/O

rustjay-engine supports multiple video input and output protocols. All device discovery runs in a background thread — the GPU render loop never blocks waiting for a camera or network source.

Video inputs

Configure the input source from the Input tab at runtime. Your shader always receives the current frame at @group(0) @binding(0) regardless of which source is active.

Webcam

Any V4L2 (Linux), AVFoundation (macOS), or DirectShow (Windows) capture device. The Input tab lists available devices by name; select one and the engine opens it at its native resolution.

No feature flag needed.

NDI

Network Device Interface — receive video from any NDI source on the LAN (OBS, Resolume, another rustjay-engine instance).

Requires the NDI SDK and the ndi feature (on by default).

The Input tab scans the LAN and shows available sources. Low latency, high resolution, suitable for multi-machine setups.

Syphon (macOS only)

Receive frames from any Syphon server on the same machine — VDMX, Resolume, Final Cut Pro, another rustjay-engine app.

Requires Syphon.framework in /Library/Frameworks/. No feature flag (always compiled on macOS).

Zero-copy GPU texture sharing — no CPU round-trip.

Spout (Windows only)

The Windows equivalent of Syphon. Receive frames from Resolume, MadMapper, or any Spout-compatible app.

Uses DirectX texture sharing. No feature flag (always compiled on Windows).

V4L2 (Linux only)

Receive from any /dev/videoN device, including loopback devices created by the v4l2loopback kernel module. Can receive video piped from OBS or ffmpeg.

Video outputs

Configure from the Output tab.

NDI output

Publish the rendered output as an NDI source on the LAN. Other NDI receivers see it immediately.

rustjay-engine = { git = "...", features = ["ndi"] }

Syphon output (macOS)

Publish as a Syphon server. VDMX, Resolume, and other VJ apps on the same machine can receive and further process the output.

Spout output (Windows)

Publish as a Spout sender for DirectX-based apps on the same machine.

V4L2 output (Linux)

Write frames to a V4L2 loopback device (/dev/videoN) so tools like OBS, ffmpeg, or Zoom can receive the output as a virtual camera.

# Create a loopback device first
sudo modprobe v4l2loopback

Resolution and frame rate

The output window renders at the resolution it was created at (typically display DPI-scaled). Output protocols (NDI, Syphon, Spout) capture the rendered frame at that resolution.

Frame rate is uncapped by default and limited by GPU rendering time. Set a target rate in the engine config if you need to control pacing.

No input

If no source is selected, the engine provides a solid-black texture at group 0 binding 0. Your shader still runs — useful for generative effects that don't need video input.