Nimio is a lightweight, flexible JavaScript player for the SLDP 2.0 protocol built on the WebCodecs API. It offers low-latency streaming, full control over audio/video pipelines, and easy integration into modern web apps.

https://nimio.pages.dev/demo - Latest

https://softvelum.com/nimio/demo/ - Stable

• SLDP Protocol (Softvelum Low Delay Protocol) - WebSocket‑based streaming with sub-100ms latency, supporting H.264, H.265/HEVC, AV1, VP8, VP9, AAC, MP3, Opus, and more.
• WebCodecs Integration - Fine‑grained control over decoding, synchronization, jitter buffering, playback speed, and debugging at each stage of the pipeline.
• Available on all web platforms - desktop, Android and recent iOS/macOS.

Read the first beta release announcement with the list of current features.

nimio = new Nimio({
  streamUrl: "ws://example.com/stream", //SLDP stream URL
  container: "#player", // CSS selector or HTMLElement
  //optional parameters:
  width: 476,
  height: 268,
  latency: 600, // Target latency in ms
  startOffset: 1000, // Startup offset in ms
  pauseTimeout: 3000, // ms until auto-stop when paused
  metricsOverlay: true, // Show overlay with performance metrics
  logLevel: "warn", // Logging verbosity
  autoplay: true, // Start playback automatically
  videoOnly: false, // Video only playback
  audioOnly: false, // Audio only playback
  muted: true, // Player is muted on start
  adaptiveBitrate: {
    initialRendition: "480p", // Default rendition which the player will set on start
    maxRendition: "1080p", // Maximum rendition that the player will set automatically
    sizeConstrained: true, // Player won't automatically switch to renditions which dimensions exceed the actual player size more then 5%
  },
  vuMeter: {
    // a volume unit (VU) meter settings object
    api: "AudioWorklet", // audio processing interface used by VU meter ("AudioWorklet" or "ScriptProcessor")
    container: "vu-meter", // ID of the VU meter container. VU meter UI  occupies the whole container's size. Vertical orientation (container's height >= width), horizontal orientation (container's width > height)
    mode: "peak", // the way which audio level values are calculated ("peak", "avg", "rms")
    type: "input", // VU meter readings type ("input" or "output")
    rate: 6, // audio level update frequency limit (from 0.001 to 50)
    dbRange: 100, // decibel scale range which is plotted in the VU meter UI
  },
});

nimio.play();

Nimio uses features (e.g. SharedArrayBuffer) that require a fully isolated browsing context.
To enable this, your server must send both the Cross‑Origin‑Opener‑Policy and Cross‑Origin‑Embedder‑Policy headers on any page or asset that loads the player.

Add these two headers:

add_header Cross-Origin-Opener-Policy  same-origin always;
add_header Cross-Origin-Embedder-Policy require-corp always;

server {
    listen 443 ssl;
    server_name example.com;

    # Serve the Nimio demo with COOP/COEP
    location ^~ /nimio/ {
        alias /usr/share/nginx/example.com/nimio/;
        index index.html;

        # Enable cross‑origin isolation
        add_header Cross-Origin-Opener-Policy  same-origin always;
        add_header Cross-Origin-Embedder-Policy require-corp always;
    }
}

These methods are available on every Nimio player instance.

• play()
  Start playback.
• pause()
  Pause playback.
• stop()
  Stop and reset the player.
• version()
  Return the current version string of this player instance.

These methods are available directly on the Nimio class.

• Nimio.version()
  Return the current version string (identical to instance.version()).

The following features are planned for upcoming releases:

• Adaptive bitrate
• Volume control
• Automatic aspect ratio detection
• Fullscreen playback
• Picture-in-Picture (PiP)
• Latency retention for asynchronous renditions
• CEA-608 closed captions
• VU meter
• VOD playback (DVR support)
• VOD thumbnail previews
• SEI timecodes support
• WebTransport protocol
• Nimble Advertizer integration
• Automatic reconnection
• Sync mode
• Screenshot capture
• Splash/startup image
• Extended Player API
• Muted autoplay
• Dynamic latency adjustment
• OffscreenCanvas rendering
• Resume from pause in DVR mode (no auto-jump to live)

Contributions are welcome! Please open an issue for discussion or submit a pull request.

Nimio released under MIT License.