teidesu-scripts/scripts/infra/navidrome-remux-m4a.ts

import { readFile, rm } from 'node:fs/promises'
import { join } from 'node:path'
import { $ } from 'zx'
import { downloadStream } from '../../utils/fetch.ts'
import { getEnv } from '../../utils/misc.ts'
import { fetchSongs } from '../../utils/navidrome.ts'
import { WebdavClient } from '../../utils/webdav.ts'

const webdav = new WebdavClient({
  baseUrl: getEnv('NAVIDROME_WEBDAV_ENDPOINT'),
  username: getEnv('NAVIDROME_WEBDAV_USERNAME'),
  password: getEnv('NAVIDROME_WEBDAV_PASSWORD'),
})

const CHUNK_SIZE = 1000
for (let offset = 0; ; offset += CHUNK_SIZE) {
  const songs = await fetchSongs(offset, CHUNK_SIZE)
  if (songs.length === 0) break

  for (const song of songs) {
    const ext = song.path.split('.').pop()!
    if (ext !== 'm4a') continue

    console.log('❌ song %s is m4a, remuxing...', song.path)
    const webdavPath = song.path.replace('/music/s3/', '/')
    const res = await webdav.get(webdavPath).catch(() => null)

    if (!res) {
      console.log('  ❌ failed to get %s', webdavPath)
      continue
    }

    const tmpfile = join('assets', `${song.id}.m4a`)
    await downloadStream(res.body!, tmpfile)
    console.log('  - downloaded to %s', tmpfile)

    const probe = await $`ffprobe -v error -show_entries stream=codec_type,codec_name,index:stream_tags=title,language -of json ${tmpfile}`.json()
    const audioStream = probe.streams.find(stream => stream.codec_type === 'audio')
    if (!audioStream) {
      console.log('  ❌ no audio stream found')
      await rm(tmpfile)
      continue
    }
    const codec = audioStream.codec_name

    if (codec !== 'flac') {
      console.log(`  ❌ audio stream is ${codec}, not flac, skipping`)
      await rm(tmpfile)
      continue
    }

    console.log('  - audio stream is flac, remuxing')

    // remux
    const remuxed = join('assets', `${song.id}.flac`)
    await rm(remuxed, { force: true })
    await $`ffmpeg -i ${tmpfile} -c:a copy ${remuxed}`.quiet(true)
    console.log('  - remuxed to %s', remuxed)
    await rm(tmpfile)

    await webdav.put(webdavPath.replace('.m4a', '.flac'), await readFile(remuxed))
    await webdav.delete(webdavPath)
    console.log('  - uploaded to %s', webdavPath.replace('.m4a', '.flac'))
    await rm(remuxed)
  }
}