Create audio system based on Web Audio API

.yarnrc

@@ -0,0 +1 @@
+--cwd front

front/package.json

@@ -38,6 +38,7 @@
     "qs": "6.11.0",
     "sass": "1.54.9",
     "showdown": "2.1.0",
+    "standardized-audio-context": "^25.3.32",
     "text-clipper": "2.2.0",
     "transliteration": "2.3.5",
     "universal-cookie": "4.0.4",

front/public/embed.html

@@ -72,8 +72,10 @@
 
       // NOTE: Add a transcoded MP3 src at the end for browsers
       //       that do not support other codecs to be able to play it :)
-      if (sources.length > 0 && !sources.some(({ type }) => type === 'audio/mpeg')) {
-        sources.push({ mimetype: 'audio/mpeg', listen_url: `${sources[0].listen_url}?to=mp3` })
+      if (sources.length > 0 && !sources.some(({ mimetype }) => mimetype === 'audio/mpeg')) {
+        const url = new URL(sources[0].listen_url)
+        url.searchParams.set('to', 'mp3')
+        sources.push({ mimetype: 'audio/mpeg', listen_url: url.toString() })
       }
 
       return sources

front/src/components/audio/Player.vue

@@ -1,14 +1,17 @@
 <script setup lang="ts">
+import { initializeFirstTrack, isPlaying, _seekEnd } from '~/composables/audio/player'
+import { useMouse, useWindowSize } from '@vueuse/core'
+import { useGettext } from 'vue3-gettext'
+import { computed, ref } from 'vue'
 import { useStore } from '~/store'
-import VolumeControl from './VolumeControl.vue'
+
+import onKeyboardShortcut from '~/composables/onKeyboardShortcut'
+import usePlayer from '~/composables/audio/usePlayer'
+import useQueue from '~/composables/audio/useQueue'
+
 import TrackFavoriteIcon from '~/components/favorites/TrackFavoriteIcon.vue'
 import TrackPlaylistIcon from '~/components/playlists/TrackPlaylistIcon.vue'
-import onKeyboardShortcut from '~/composables/onKeyboardShortcut'
-import { computed, ref } from 'vue'
-import { useGettext } from 'vue3-gettext'
-import { useMouse, useWindowSize } from '@vueuse/core'
-import useQueue from '~/composables/audio/useQueue'
-import usePlayer from '~/composables/audio/usePlayer'
+import VolumeControl from './VolumeControl.vue'
 
 const store = useStore()
 const { $pgettext } = useGettext()
@@ -97,6 +100,10 @@ const touchProgress = (event: MouseEvent) => {
 
 const { x } = useMouse()
 const { width: screenWidth } = useWindowSize()
+
+initializeFirstTrack()
+onKeyboardShortcut('w', () => { isPlaying.value = !isPlaying.value })
+onKeyboardShortcut('9', () => { _seekEnd() })
 </script>
 
 <template>

front/src/composables/audio/audio-api.ts

@@ -0,0 +1,36 @@
+import type { IAudioContext, IMediaElementAudioSourceNode } from 'standardized-audio-context'
+
+import { AudioContext } from 'standardized-audio-context'
+import { useEventListener } from '@vueuse/core'
+
+// Audio nodes
+const AUDIO_CONTEXT = new AudioContext()
+const GAIN_NODE = AUDIO_CONTEXT.createGain()
+
+// Unlock AudioContext automatically
+const UNLOCK_EVENTS = ['touchstart', 'touchend', 'mousedown', 'keydown']
+for (const event of UNLOCK_EVENTS) {
+  const stop = useEventListener(window, event, () => {
+    AUDIO_CONTEXT.resume()
+    stop()
+  }, { passive: true })
+}
+
+// Connect Gain Node
+GAIN_NODE.connect(AUDIO_CONTEXT.destination)
+GAIN_NODE.gain.value = 1
+
+// TODO (wvffle): Create equalizer filters
+const equalizerFilters = [
+  GAIN_NODE
+]
+
+export const connectAudioSource = (sourceNode: IMediaElementAudioSourceNode<IAudioContext>) => {
+  for (const filter of equalizerFilters) {
+    sourceNode.connect(filter)
+  }
+}
+
+export const createAudioSource = (sourceElement: HTMLAudioElement) => {
+  return AUDIO_CONTEXT.createMediaElementSource(sourceElement)
+}

front/src/composables/audio/player.ts

@@ -0,0 +1,33 @@
+import { getCurrentSound, createTrack } from '~/composables/audio/tracks'
+import { tryOnMounted } from '@vueuse/core'
+import { ref, watch } from 'vue'
+
+import useQueue from '~/composables/audio/useQueue'
+
+const { currentIndex } = useQueue()
+
+export const isPlaying = ref(false)
+
+watch(isPlaying, (playing) => {
+  const sound = getCurrentSound()
+  if (!sound) return
+
+  if (playing) {
+    sound.audio.play()
+    return
+  }
+
+  sound.audio.pause()
+})
+
+// Create first track when we initalize the page
+export const initializeFirstTrack = () => tryOnMounted(() => {
+  createTrack(currentIndex.value)
+})
+
+export const _seekEnd = () => {
+  const sound = getCurrentSound()
+  if (!sound) return
+
+  sound.audio.currentTime = sound.audio.duration - 3
+}

front/src/composables/audio/tracks.ts

@@ -0,0 +1,133 @@
+import type { IAudioContext, IMediaElementAudioSourceNode } from 'standardized-audio-context'
+import type { Track, Upload } from '~/types'
+
+import { connectAudioSource, createAudioSource } from '~/composables/audio/audio-api'
+import { isPlaying } from '~/composables/audio/player'
+
+import useQueue from '~/composables/audio/useQueue'
+
+import { useEventListener } from '@vueuse/core'
+
+import store from '~/store'
+import axios from 'axios'
+
+export interface SoundSource {
+  uuid: string
+  mimetype: string
+  url: string
+}
+
+export interface Sound {
+  audio: HTMLAudioElement
+  sources: SoundSource[]
+  sourceNode: IMediaElementAudioSourceNode<IAudioContext>
+}
+
+const ALLOWED_PLAY_TYPES: (CanPlayTypeResult | undefined)[] = ['maybe', 'probably']
+const AUDIO_ELEMENT = document.createElement('audio')
+
+const { tracks, currentIndex } = useQueue()
+
+const soundPromises = new Map<number, Promise<Sound>>()
+const soundCache = new Map<number, Sound>()
+
+const getUploadSources = (uploads: Upload[]): SoundSource[] => {
+  const sources = uploads
+    // NOTE: Filter out repeating and unplayable media types
+    .filter(({ mimetype }, index, array) => array.findIndex((upload) => upload.mimetype === mimetype) === index)
+    .filter(({ mimetype }) => ALLOWED_PLAY_TYPES.includes(AUDIO_ELEMENT.canPlayType(`${mimetype}`)))
+    .map((upload): SoundSource => ({
+      ...upload,
+      url: store.getters['instance/absoluteUrl'](upload.listen_url) as string
+    }))
+
+  // NOTE: Add a transcoded MP3 src at the end for browsers
+  //       that do not support other codecs to be able to play it :)
+  if (sources.length > 0 && !sources.some(({ mimetype }) => mimetype === 'audio/mpeg')) {
+    const url = new URL(sources[0].url)
+    url.searchParams.set('to', 'mp3')
+    sources.push({ uuid: 'transcoded', mimetype: 'audio/mpeg', url: url.toString() })
+  }
+
+  return sources
+}
+
+const getTrackSources = async (track: Track): Promise<SoundSource[]> => {
+  if (track === undefined) return []
+
+  if (track.uploads.length === 0) {
+    // we don't have any information for this track, we need to fetch it
+    const { uploads } = await axios.get(`tracks/${track.id}/`)
+      .then(response => response.data as Track, () => ({ uploads: [] as Upload[] } as Track))
+
+    track.uploads = uploads
+  }
+
+  return getUploadSources(track.uploads)
+}
+
+export const createSound = async (track: Track): Promise<Sound> => {
+  if (soundCache.has(track.id)) {
+    return soundCache.get(track.id) as Sound
+  }
+
+  if (soundPromises.has(track.id)) {
+    return soundPromises.get(track.id) as Promise<Sound>
+  }
+
+  const createSoundPromise = async () => {
+    const sources = await getTrackSources(track)
+
+    const audio = new Audio()
+    audio.src = sources[0].url
+
+    const sourceNode = createAudioSource(audio)
+
+    const sound = { audio, sources, sourceNode }
+    soundCache.set(track.id, sound)
+    soundPromises.delete(track.id)
+    return sound
+  }
+
+  const soundPromise = createSoundPromise()
+  soundPromises.set(track.id, soundPromise)
+  return soundPromise
+}
+
+// Create track from queue
+export const createTrack = async (index: number) => {
+  if (tracks.value.length <= index || index === -1) return
+  console.log('LOADING TRACK')
+
+  const track = tracks.value[index]
+  if (!soundPromises.has(track.id) && !soundCache.has(track.id)) {
+    // TODO (wvffle): Resolve race condition
+    console.log('NO TRACK IN CACHE, CREATING')
+  }
+
+  const sound = await createSound(track)
+  console.log('CONNECTING NODE')
+
+  const stop = useEventListener(sound.audio, 'ended', () => {
+    createTrack(currentIndex.value + 1)
+    store.dispatch('queue/next')
+    stop()
+  })
+
+  sound.sourceNode.disconnect()
+  connectAudioSource(sound.sourceNode)
+
+  if (isPlaying.value) {
+    sound.audio.play()
+  }
+
+  // NOTE: Preload next track
+  if (index + 1 < tracks.value.length) {
+    createSound(tracks.value[index + 1])
+      .then(sound => sound.audio.load())
+  }
+}
+
+export const getCurrentSound = () => {
+  return soundCache.get(tracks.value[currentIndex.value]?.id ?? -1)
+}

front/src/composables/audio/usePlayer.ts

@@ -231,7 +231,6 @@ const togglePlayback = () => {
   if (playing.value) return pause()
   return resume()
 }
-
 export default () => {
   return {
     looping,