HEVC Plugin for Shaka Player

$ npm install @hevcjs/shaka-plugin shaka-player

registerHevcTransmuxer(shaka, config?)

Registers the Shaka transmuxer for HEVC mime types. Returns a cleanup() function that unregisters it.

const cleanup = registerHevcTransmuxer(shaka, {
  workerUrl:     '/transcode-worker.js',   // Web Worker URL
  wasmUrl:       '/hevc-decode.js',         // WASM glue location
  wasmBinaryUrl: '/hevc-decode.wasm',       // WASM binary location
});

// Force the transmuxer even on browsers with native HEVC
player.configure({ mediaSource: { forceTransmux: true } });

// Unregister when done
cleanup();

Options

adaptiveCompute — compute-aware ABR on by default

Feedback loop that caps Shaka variants when the device can't sustain transcoding at real-time. Shaka's bandwidth-based ABR keeps choosing freely — we only narrow the ceiling it's allowed to pick from. Useful on devices where WASM HEVC decode + WebCodecs H.264 encode runs slower than playback (typical on low-end Windows boxes at 1080p+). On by default — pass adaptiveCompute: false to opt out.

// Default — adaptiveCompute is ON, defaults are sensible
const handle = registerHevcTransmuxer(shaka, {
  workerUrl: '/transcode-worker.js',
});

// To tune knobs:
// registerHevcTransmuxer(shaka, { adaptiveCompute: { targetSpeedX: 1.5 } })
// To opt out:
// registerHevcTransmuxer(shaka, { adaptiveCompute: false })

const player = new shaka.Player();
const detach = handle.attachComputeAware(player); // after player exists
await player.load(manifestUrl);

// Cleanup
detach();    // stop observing
handle();    // unregister transmuxer + detach

Tuning knobs

Caps are applied via Shaka's public player.configure({ abr: { restrictions: { maxHeight, maxBandwidth } } }) — no fork of the ABR controller, no reach into private APIs.