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 +1,286 @@
+/**
+ * Lightweight demuxer — replaces node-av's LibavDemuxer for GoLive.
+ *
+ * Spawns ffmpeg to remux input into H264 AnnexB on stdout (video only —
+ * screen share doesn't need to mux audio into the demuxer; audio goes
+ * separately). This replaces the 114MB node-av binary with a plain ffmpeg
+ * spawn.
+ *
+ * Each video "frame" emitted is a complete NAL sequence terminated by a
+ * keyframe boundary (IDR). Audio is not extracted here — for GoLive with
+ * audio, the NUT mux + full demuxer would be needed; screen share audio is
+ * handled via a separate ffmpeg instance (see getDirectScreenInput).
+ */
+
+import { spawn } from "node:child_process";
+import { randomUUID } from "node:crypto";
+import { PassThrough } from "node:stream";
+
+export enum AVCodecID {
+  AV_CODEC_ID_H264 = 27,
+  AV_CODEC_ID_HEVC = 173,
+  AV_CODEC_ID_VP8 = 139,
+  AV_CODEC_ID_VP9 = 167,
+  AV_CODEC_ID_AV1 = 225,
+  AV_CODEC_ID_OPUS = 86019,
+}
+
+export const AV_PKT_FLAG_KEY = 1;
+
+export interface Frame {
+  data: Buffer | null;
+  pts: number;
+  duration: number;
+  timeBase: { num: number; den: number };
+  flags: number;
+  streamIndex: number;
+  free(): void;
+}
+
+export interface DemuxedStream {
+  codec: number;
+  codecName: string;
+  width: number;
+  height: number;
+  framerate_num: number;
+  framerate_den: number;
+  sample_rate: number;
+  stream: PassThrough;
+}
+
+/** Run ffprobe JSON on a file URL, return raw stream descriptors. */
+export async function probeStreams(
+  url: string,
+): Promise<Array<Record<string, unknown>>> {
+  return new Promise((resolve, reject) => {
+    const proc = spawn("ffprobe", [
+      "-hide_banner",
+      "-loglevel",
+      "error",
+      "-i",
+      url,
+      "-print_format",
+      "json",
+      "-show_streams",
+    ]);
+    let stdout = "";
+    let stderr = "";
+    proc.stdout.on("data", (d: Buffer) => (stdout += d.toString()));
+    proc.stderr.on("data", (d: Buffer) => (stderr += d.toString()));
+    proc.on("close", (code) => {
+      if (code === 0) {
+        try {
+          const parsed = JSON.parse(stdout);
+          resolve(parsed.streams ?? []);
+        } catch (e) {
+          reject(new Error(`Failed to parse ffprobe output: ${e}`));
+        }
+      } else {
+        reject(new Error(`ffprobe failed (${code}): ${stderr}`));
+      }
+    });
+  });
+}
+
+/**
+ * Demux input (URL string or readable stream) into video frames on a
+ * PassThrough. Uses ffmpeg -f h264 -c copy for video-only AnnexB output.
+ * Returns stream info + the video pipe. Audio is not extracted (GoLive
+ * screen share sends silence / uses Discord's mixed audio).
+ */
+export async function demux(
+  input: string | PassThrough,
+  _opts: { format: string },
+): Promise<{
+  video: DemuxedStream | undefined;
+  audio: DemuxedStream | undefined;
+  close: () => void;
+}> {
+  const _label = randomUUID();
+  const vPipe = new PassThrough({ objectMode: true, highWaterMark: 128 });
+  const aPipe = new PassThrough({ objectMode: true, highWaterMark: 128 });
+
+  // Probe for codec + dimensions
+  let streams: Array<Record<string, unknown>> = [];
+  if (typeof input === "string") {
+    streams = await probeStreams(input);
+  }
+
+  const v = streams.find((s) => s.codec_type === "video");
+  const a = streams.find((s) => s.codec_type === "audio");
+
+  let vInfo: DemuxedStream | undefined;
+  let aInfo: DemuxedStream | undefined;
+
+  if (v) {
+    const codecName = (v.codec_name as string) ?? "h264";
+    const rFrame = (v.r_frame_rate as string) ?? "0/1";
+    const [num, den] = rFrame.split("/").map((n) => Number(n));
+    vInfo = {
+      codec:
+        AVCodecID[
+          (codecName.toUpperCase() as keyof typeof AVCodecID) ??
+            "AV_CODEC_ID_H264"
+        ],
+      codecName,
+      width: (v.width as number) ?? 0,
+      height: (v.height as number) ?? 0,
+      framerate_num: num ?? 0,
+      framerate_den: den ?? 1,
+      sample_rate: 0,
+      stream: vPipe,
+    };
+  }
+
+  if (a) {
+    const codecName = (a.codec_name as string) ?? "opus";
+    aInfo = {
+      codec:
+        AVCodecID[
+          (codecName.toUpperCase() as keyof typeof AVCodecID) ??
+            "AV_CODEC_ID_OPUS"
+        ],
+      codecName,
+      width: 0,
+      height: 0,
+      framerate_num: 0,
+      framerate_den: 0,
+      sample_rate: Number(a.sample_rate) ?? 0,
+      stream: aPipe,
+    };
+  }
+
+  // Spawn ffmpeg — extract raw video (AnnexB for H264) to stdout
+  const isUrl = typeof input === "string";
+  const args: string[] = [
+    "-hide_banner",
+    "-loglevel",
+    "error",
+    ...(isUrl ? ["-i", input] : ["-i", "pipe:0"]),
+    "-c:v",
+    "copy",
+    "-an", // no audio in this minimal demuxer
+    "-f",
+    "h264",
+    "pipe:1",
+  ];
+
+  const proc = isUrl
+    ? spawn("ffmpeg", args, { stdio: ["ignore", "pipe", "pipe"] })
+    : spawn("ffmpeg", args, { stdio: ["pipe", "pipe", "pipe"] });
+
+  if (proc.stdin && !isUrl) {
+    input.on("data", (chunk: Buffer) => proc.stdin?.write(chunk));
+    input.on("end", () => proc.stdin?.end());
+    input.on("error", () => proc.stdin?.destroy());
+  }
+
+  // Scan stdout for NAL units. Each NAL unit (between start codes) is one frame
+  // payload. We emit them individually; the packetizer chain handles FU-A.
+  let videoBuf = Buffer.alloc(0);
+  let frameCount = 0;
+
+  const emitFrame = (nal: Uint8Array, isKeyFrame: boolean) => {
+    vPipe.write({
+      data: Buffer.from(nal),
+      pts: frameCount,
+      duration: 1,
+      timeBase: { num: 1, den: 90000 },
+      flags: isKeyFrame ? AV_PKT_FLAG_KEY : 0,
+      streamIndex: 0,
+      free: () => {},
+    });
+    frameCount++;
+  };
+
+  if (proc.stdout) {
+    proc.stdout.on("data", (chunk: Buffer) => {
+      videoBuf = Buffer.concat([videoBuf, chunk]);
+      // Find start codes (00 00 01 or 00 00 00 01) and split NALs
+      let start = 0;
+      // If buffer starts with zeros, that's the first start code — emit from there
+      while (start < videoBuf.length) {
+        let scPos = -1;
+        for (let i = start + 1; i < videoBuf.length - 2; i++) {
+          if (
+            videoBuf[i] === 0 &&
+            videoBuf[i + 1] === 0 &&
+            videoBuf[i + 2] === 1
+          ) {
+            scPos = i + 3;
+            break;
+          }
+        }
+        if (scPos === -1) break;
+        // Emit the NAL from `start` to `scPos` (but skip the start code bytes at `start`)
+        if (start < scPos) {
+          let nalStart = start;
+          // Skip start code bytes for the NAL itself (00 00 01)
+          if (
+            videoBuf[nalStart] === 0 &&
+            videoBuf[nalStart + 1] === 0 &&
+            videoBuf[nalStart + 2] === 1
+          ) {
+            nalStart += 3;
+          } else if (
+            nalStart + 3 < scPos &&
+            videoBuf[nalStart] === 0 &&
+            videoBuf[nalStart + 1] === 0 &&
+            videoBuf[nalStart + 2] === 0 &&
+            videoBuf[nalStart + 3] === 1
+          ) {
+            nalStart += 4;
+          }
+          const nal = videoBuf.subarray(nalStart, scPos);
+          // Trim trailing zero bytes (from start code overlap)
+          let end = nal.length;
+          while (end > 0 && nal[end - 1] === 0) end--;
+          if (end > 0) {
+            const nalTrimmed = nal.subarray(0, end);
+            const isIdr = (nalTrimmed[0] & 0x1f) === 5; // IDR
+            emitFrame(nalTrimmed, isIdr);
+          }
+        }
+        // Skip the 00 00 01 at scPos-3 to find next
+        start = scPos;
+        // But the next start code needs at least 3 bytes
+        if (start > videoBuf.length - 3) break;
+      }
+      // Keep remaining bytes (potential partial NAL or start code)
+      if (start > 0 && start < videoBuf.length) {
+        videoBuf = videoBuf.subarray(start);
+      } else if (videoBuf.length > 4) {
+        // No full NAL found, but avoid unbounded growth
+        // Keep a sliding window
+        videoBuf = videoBuf.subarray(videoBuf.length - 3);
+      }
+    });
+    proc.stdout.on("end", () => {
+      if (videoBuf.length > 0) {
+        let end = videoBuf.length;
+        while (end > 0 && videoBuf[end - 1] === 0) end--;
+        if (end > 0) emitFrame(videoBuf.subarray(0, end), false);
+      }
+      vPipe.end();
+      aPipe.end();
+    });
+  }
+
+  if (proc.stderr) {
+    proc.stderr.on("data", () => {
+      /* errors swallowed */
+    });
+  }
+  proc.on("close", () => {
+    vPipe.end();
+    aPipe.end();
+  });
+
+  const close = () => {
+    proc.kill("SIGTERM");
+    vPipe.end();
+    aPipe.end();
+  };
+
+  return { video: vInfo, audio: aInfo, close };
+}