streamMetadataOverride(settings: StreamMetadataOverrideSettings): Promise<StreamMetadataOverrideNode>;

// SRT inputs do not have bitrate information, which is required for HLS
// master playlists.
//
// AAC audio does not need a transcode in this setting, and without a
// transcode (implicit or explicit), there is no bitrate information added.
let srtAacInput = await norsk.input.srt(srtSettings);

// So we sample the stream for 10 seconds to estimate its bitrate and add this
// bitrate to the stream's metadata before subscribing the master playlist to
// the stream.
let streamStarted = false;
let streamStatistics = await norsk.processor.control.streamStatistics({
  id: "inputStreamStatistics",
  statsSampling: {
    // 1s for visualiser updates
    // 5s for console updates
    // 10s for stream bitrate estimation
    sampleIntervalsSeconds: [1, 5, 10],
  },
  onStreamStatistics: async stats => {
    let { audio, video } = stats;
    if (stats.sampleSizeSeconds === 10) {
      if (streamStarted) return;
      streamStarted = true;
      console.log(`+ audio: ${(audio.bitrate / 1000).toFixed(1)}kbps`)
      console.log(`+ video: ${(video.bitrate / 1000).toFixed(1)}kbps`);

      // Use NorskTransform.streamMetadataOverride to add bitrate information
      // to the video and audio streams
      streamMetadataOverride.updateConfig({
        video: {
          bitrate: video.bitrate,
        },
        audio: {
          bitrate: audio.bitrate,
        }
      });

      // And subscribe the master playlist, now that the stream has bitrate
      // metadata
      masterOutput.subscribe([
        { source: streamMetadataOverride, sourceSelector: selectAV },
      ]);
    } else if (stats.sampleSizeSeconds === 5 && streamStarted) {
      console.log(`  audio: ${(audio.bitrate / 1000).toFixed(1)}kbps`)
      console.log(`  video: ${(video.bitrate / 1000).toFixed(1)}kbps`);
    }
  },
});
streamStatistics.subscribe([
  { source: srtAacInput, sourceSelector: selectAV },
]);

let streamMetadataOverride = await norsk.processor.transform.streamMetadataOverride({
  id: "setBitrate",
});
streamMetadataOverride.subscribe([
  { source: srtAacInput, sourceSelector: selectAV },
]);

ffmpeg -v error -re -f lavfi -i "sine=frequency=220:sample_rate=48000" -loop 1 -i data/test-src-still.png -vf drawtext=fontfile=Arial.ttf:text="%{frame_num}":start_number=1:x=980:y=330:fontcolor=black:fontsize=40:box=1:boxcolor=white:boxborderw=5,scale=1280:720 -vcodec h264 -b:v 150000 -b:a 20000 -aspect 1280:720 -x264opts "keyint=25:min-keyint=25:no-scenecut:bframes=0" -bluray-compat true -tune stillimage -preset fast -pix_fmt yuv420p -acodec aac -metadata language=en -f mpegts -flush_packets 0 'srt://127.0.0.1:5001'