Декодирование потока видео на node

Есть такая проблема в браузере нет звука для формата mkv как можно конвентировать на лету поток стрима?

router.get('/:magnet/:fileName', (req: Request, res: Response, next: NextFunction) => {
  const { 
    params: { magnet, fileName },
    headers: { range }
  } = req

  if(!range) {
    const err = new Error('Range is not defined, please make request from HTML5 Player') as ErrorWithStatuses
    err.status = 416
    return next(err)
  }

  const torrentFile = client.get(magnet) as Torrent
  let file = <TorrentFile> {}

  for(let i = 0; i < torrentFile.files.length; i++) {
    const currentTorrentPiece = torrentFile.files[i]
    if(currentTorrentPiece.name === fileName) {
      file = currentTorrentPiece
    }
  }

  const fileSize = file.length
  const [startParsed, endParsed] = range.replace(/bytes=/, '').split('-')

  const start = Number(startParsed)
  const end = endParsed ? Number(endParsed) : fileSize - 1

  const chunkSize = end - start + 1

  const headers = {
    'Content-Range': `bytes ${start}-${end}/${fileSize}`,
    'Accept-Ranges': 'bytes',
    'Content-Length': chunkSize,
    'Content-Type': 'video/mp4'
  }

  res.writeHead(206, headers)

  const streamPositions = {
    start,
    end
  }

  const stream = file.createReadStream(streamPositions)

  stream.pipe(res)

  stream.on('error', err => {
    return next(err)
  })
})```

Я пробовал нарезать через ffmpeg но не получилось

const stream = file.createReadStream(streamPositions)
    .on("open", function() {
      ffmpeg()
        .input(stream)
        .outputFormat('mp4')
        .outputOptions([ '-movflags faststart', '-frag_size 4096', '-cpu-used 2', '-deadline realtime', '-threads 4' ])
        .videoBitrate(640, true)
        .audioBitrate(128)
        .audioCodec('aac')
        .videoCodec('libx264')
        .stream()
        .pipe(res, { end: true})
    }).on("error", function(err) {
      console.error('Ffmpeg conversion error:', err);
      res.end(err)
    })