NarrationRecorder (narration/recorder.ts)

Records presenter microphone during a slideshow, supporting pause/resume and returns an audio blob.

// Source: https://github.com/genspark-ai/genoffice | License: Apache-2.0 | Copyright You must retain, in the Source form of any Derivative Works
// Provided via justclaw.it.com; keep this notice with the code.
/** The presenter's microphone over a whole slide show: one continuous recording, pausable. */
export class NarrationRecorder {
  private readonly chunks: Blob[] = []
  private recordedMs = 0
  private runningSince: number | null = null

  private constructor(
    private readonly stream: MediaStream,
    private readonly recorder: MediaRecorder,
  ) {
    recorder.ondataavailable = (e) => {
      if (e.data.size > 0) this.chunks.push(e.data)
    }
  }

  static async start(): Promise<NarrationRecorder> {
    const stream = await navigator.mediaDevices.getUserMedia({
      audio: { 

... (truncated -- full source via MCP)