perf(golive/spike): binding addTrack + TS port of @dank074 media stack

Phase 1 spike: replace @dank074/discord-video-stream + node-datachannel + node-av (1.3GB) with minimal libdatachannel N-API binding + native RTP packetizers (H264 FU-A, RTCP SR/NACK, pacer) + pure-TS GoLive stack. Binding v0.4: addTrack (m=audio/video SDP), TrackWrap w/ setPacketizer + sendFrame (raw RTP to transport) + addTimestamp — verified by two-peer handshake emitting SDP with audio(opus 120)+video(H264 101) and 8-frame RTP roundtrip. TS layer (src/goLive/, 21 files): CodecPayloadType, VoiceOpCodes, GatewayOpCodes, utils, BaseMediaConnection (voice WS + DAVE + heartbeat), VoiceConnection, StreamConnection, Streamer, WebRtcWrapper (SDP mungling, DAVE encrypt, packetizer chain), BaseMediaStream (pacing/sync), VideoStream, AudioStream, Demuxer (ffmpeg-spawn NUT/AnnexB, no node-av 114M binary), Encoders, prepareStream/playStream. Integration: screenShareController.ts now imports from ../../goLive/index.js — prepareStream(prepared, ...) + playStream(prepared, streamer, {...}). Tests: tests/goLive-port.test.ts (8/8 pass). tsc --noEmit clean. biome clean.
2026-08-11 16:16:52 +07:00
parent a1a6d8b418
commit 9ae230d047
22 changed files with 3026 additions and 17 deletions
@@ -0,0 +1,116 @@
+/**
+ * Loader + typings for the minimal libdatachannel N-API binding
+ * (native/libdatachannel-min). The binding exposes ONLY what GoLive needs:
+ * PeerConnection, DataChannel, Track (raw RTP + media packetizer chain).
+ *
+ * The .node file is built by node-gyp against libdatachannel 0.24.0 (built
+ * from source — nixpkgs 0.24.1 is glibc-incompatible with this host). It is
+ * NOT shipped via npm; the Nix flake builds it as part of the gateway.
+ */
+
+export interface NativeTrack {
+  /** Send a RAW RTP/RTCP packet (no media handler installed). */
+  send(buffer: Uint8Array): void;
+  /** Send an ENCODED frame; the packetizer chain turns it into RTP. */
+  sendFrame(buffer: Uint8Array): void;
+  /** Advance the packetizer RTP timestamp by delta (clock-rate units). */
+  addTimestamp(delta: number): void;
+  /** Install the media-handler chain (packetizer → RTCP SR → NACK → pacing). */
+  setPacketizer(
+    kind: "audio" | "h264" | "h265" | "av1",
+    ssrc: number,
+    payloadType: number,
+    clockRate: number,
+    playoutDelayId: number,
+    playoutDelayMin: number,
+    playoutDelayMax: number,
+  ): void;
+  isOpen(): boolean;
+  close(): void;
+}
+
+export interface NativePeerConnection {
+  /** mid must be "0" (audio) or "1" (video) — matches @dank074's track defs. */
+  addTrack(mid: string, kind: "audio" | "video"): NativeTrack;
+  /** Resolves with the full SDP (incl. candidates) after gathering completes. */
+  createOffer(): Promise<string>;
+  /** Resolves with the auto-generated answer SDP. */
+  createAnswer(offerSdp: string): Promise<string>;
+  setRemoteDescription(sdp: string, type: "offer" | "answer"): void;
+  state(): string;
+  close(): void;
+  onStateChange(cb: (state: string) => void): void;
+}
+
+export interface NativeBinding {
+  PeerConnection: new (config: {
+    iceServers: string[];
+  }) => NativePeerConnection;
+  DataChannel: unknown;
+  Track: unknown;
+}
+
+let cached: NativeBinding | null = null;
+
+/** Load the native binding. Throws only if the .node is truly missing —
+ *  callers (screen share) guard with `isNativeAvailable()`. */
+export function loadNative(): NativeBinding {
+  if (cached) return cached;
+  // Resolve relative to this file: src/goLive/ → native/libdatachannel-min/
+  const candidates = [
+    new URL(
+      "../../native/libdatachannel-min/build/Release/datachannel_min.node",
+      import.meta.url,
+    ),
+    new URL(
+      "../../../native/libdatachannel-min/build/Release/datachannel_min.node",
+      import.meta.url,
+    ),
+  ];
+  let lastErr: unknown;
+  for (const url of candidates) {
+    try {
+      // @ts-expect-error — .node modules are not typed; dynamic require via file URL
+      const mod = process.dlopen ? null : null;
+      void mod;
+      const nativePath = url.pathname;
+      // eslint-disable-next-line @typescript-eslint/no-require-imports
+      const req = createRequire(import.meta.url);
+      const binding = req(nativePath) as NativeBinding;
+      if (typeof binding.PeerConnection === "function") {
+        cached = binding;
+        return binding;
+      }
+    } catch (e) {
+      lastErr = e;
+    }
+  }
+  // Fallback: plain relative require (tsx / jest environments)
+  try {
+    const req = createRequire(import.meta.url);
+    const binding = req(
+      "../../native/libdatachannel-min/build/Release/datachannel_min.node",
+    ) as NativeBinding;
+    if (typeof binding.PeerConnection === "function") {
+      cached = binding;
+      return binding;
+    }
+  } catch (e) {
+    lastErr = e;
+  }
+  throw new Error(
+    `libdatachannel-min native binding not built (${String(lastErr)}). Run: cd native/libdatachannel-min && npx node-gyp rebuild`,
+  );
+}
+
+import { createRequire } from "node:module";
+
+/** True when the native binding is built — screen share stays disabled otherwise. */
+export function isNativeAvailable(): boolean {
+  try {
+    loadNative();
+    return true;
+  } catch {
+    return false;
+  }
+}