Method start

tracker/src/video/recorder.ts:75–115

Begin a clip. Idempotent: a second call while recording is a no-op.

()

  /** Begin a clip. Idempotent: a second call while recording is a no-op. */
  start(): VideoRecStatus & { error?: string } {
    if (this.proc) return this.status();
    if (!this.url) return { recording: false, error: "no camera stream" };
    mkdirSync(this.dir, { recursive: true });
    const stamp = new Date().toISOString().replace(/[:.]/g, "-").replace("Z", "");
    const name = `clip-${stamp}.mp4`;
    const path = join(this.dir, name);
    const args = [
      "-hide_banner", "-loglevel", "error",
      "-rtsp_transport", "tcp",
      "-i", this.url,
      "-an", "-c:v", "copy",
      "-movflags", "+frag_keyframe+empty_moov+default_base_moof",
      "-f", "mp4",
      path,
    ];
    // stdin piped so we can send 'q' for a graceful finalize on stop.
    const proc = spawn("ffmpeg", args, { stdio: ["pipe", "ignore", "pipe"] });
    this.proc = proc;
    this.current = { name, path, startedAt: Date.now() };
    this.track = [];
    let errTail = "";
    proc.stderr?.on("data", (c: Buffer) => {
      errTail = (errTail + c.toString()).slice(-400);
    });
    proc.on("exit", (code) => {
      if (this.proc !== proc) return;
      const finished = this.current;
      this.proc = null;
      this.current = null;
      if (code) {
        console.error(`[rec-video] ffmpeg exited (${code}): ${errTail.trim().split("\n").pop() ?? ""}`);
      }
      // Clean finish with a logged track -> auto-stabilize in the background.
      if (finished && existsSync(`${finished.path}.track.json`)) {
        this.autoStabilize(finished.path);
      }
    });
    console.log(`[rec-video] -> ${path}`);
    return this.status();
  }

  /** Stop the current clip, finalizing the file gracefully. */
  stop(): void {