Merge pull request #534 from ogg-decoder

.eslintignore

@@ -1,4 +1,5 @@
 **/node_modules/**/*
+**/vendor/**/*
 **/lib/**/*
 **/dist/**/*
 **/build/**/*

.prettierignore

@@ -1,4 +1,5 @@
 **/node_modules/**/*
+**/vendor/**/*
 **/lib/**/*
 **/dist/**/*
 **/build/**/*

src/sampling-master/index.js

@@ -1,15 +1,21 @@
 import defaultAudioContext from 'bemuse/audio-context'
 import readBlob from 'bemuse/utils/read-blob'
+import { decodeOGG } from './ogg'
 
 export const FADE_LENGTH = 0.001
 
 let dummyAudioTag = document.createElement('audio')
-
 // Checks whether an audio format is supported.
 export function canPlay(type) {
+  // We have a Vorbis audio decoder!
+  if (type === 'audio/ogg; codecs="vorbis"') return true
   return dummyAudioTag.canPlayType(type) === 'probably'
 }
 
+const needsVorbisDecoder = !dummyAudioTag.canPlayType(
+  'audio/ogg; codecs="vorbis"'
+)
+
 // The sampling master is a wrapper class around Web Audio API
 // that takes care of:
 //
@@ -92,6 +98,17 @@ export class SamplingMaster {
 
   _decodeAudio(arrayBuffer) {
     return new Promise((resolve, reject) => {
+      if (needsVorbisDecoder && arrayBuffer.byteLength > 4) {
+        const view = new Uint8Array(arrayBuffer, 0, 4)
+        if (
+          view[0] === 0x4f &&
+          view[1] === 0x67 &&
+          view[2] === 0x67 &&
+          view[3] === 0x53
+        ) {
+          return resolve(decodeOGG(this.audioContext, arrayBuffer))
+        }
+      }
       this.audioContext.decodeAudioData(
         arrayBuffer,
         function decodeAudioDataSuccess(audioBuffer) {

src/sampling-master/ogg.js

@@ -0,0 +1,92 @@
+import throat from 'throat'
+
+let decoderPromise
+
+const limit = throat(1)
+
+/**
+ * Decodes an OGG file using stbvorbis.js.
+ *
+ * @param {AudioContext} audioContext
+ * @param {ArrayBuffer} arrayBuffer
+ */
+export async function decodeOGG(audioContext, arrayBuffer) {
+  if (!decoderPromise) {
+    decoderPromise = import(/* webpackChunkName: 'stbvorbis' */ 'raw-loader!./vendor/stbvorbis/stbvorbis-e6da5fe.js')
+      .then(ns => ns.default)
+      .then(src => {
+        // eslint-disable-next-line no-eval
+        return (0, eval)(src + ';stbvorbis')
+      })
+  }
+  const stbvorbis = await decoderPromise
+  return limit(
+    () =>
+      new Promise((resolve, reject) => {
+        const buffers = []
+        let totalLength = 0
+        let sampleRate
+        stbvorbis.decode(arrayBuffer, function(e) {
+          if (e.data) {
+            sampleRate = e.sampleRate
+            buffers.push(e.data)
+            totalLength += e.data[0].length
+          }
+          if (e.error) {
+            reject(
+              e.error instanceof Error
+                ? e.error
+                : `stbvorbis.js Error: ${e.error}`
+            )
+          }
+          if (e.eof) {
+            resolve(
+              createBuffer(audioContext, buffers, totalLength, sampleRate)
+            )
+          }
+        })
+      })
+  )
+}
+
+/**
+ * @param {AudioContext} audioContext
+ * @param {Float32Array[]} decodedChunks
+ * @param {number} totalLength
+ * @param {number} sampleRate
+ */
+async function createBuffer(
+  audioContext,
+  decodedChunks,
+  totalLength,
+  sampleRate
+) {
+  if (!totalLength) {
+    throw new Error(`stbvorbis.js Error: No length`)
+  }
+  if (!sampleRate) {
+    throw new Error(`stbvorbis.js Error: No sample rate`)
+  }
+  var audioBuffer = audioContext.createBuffer(
+    decodedChunks[0].length,
+    totalLength,
+    sampleRate
+  )
+  var track = Array(audioBuffer.numberOfChannels)
+    .fill()
+    .map(() => 0)
+  var data = Array(audioBuffer.numberOfChannels)
+    .fill()
+    .map((_, ch) => audioBuffer.getChannelData(ch))
+  for (const chunk of decodedChunks) {
+    chunk.forEach(function(a, ch) {
+      // buf.copyToChannel(a, ch, track[ch]) — not supported in iOS Safari!
+      var offset = track[ch]
+      for (var i = 0; i < a.length; i++) {
+        data[ch][i + offset] = a[i]
+      }
+      track[ch] += a.length
+    })
+  }
+  return audioBuffer
+}

src/sampling-master/vendor/stbvorbis/README.md

@@ -0,0 +1 @@
+https://github.com/hajimehoshi/stbvorbis.js