First release

node_modules/@videojs/vhs-utils/es/opus-helpers.js

@@ -0,0 +1,52 @@
+export var OPUS_HEAD = new Uint8Array([// O, p, u, s
+0x4f, 0x70, 0x75, 0x73, // H, e, a, d
+0x48, 0x65, 0x61, 0x64]); // https://wiki.xiph.org/OggOpus
+// https://vfrmaniac.fushizen.eu/contents/opus_in_isobmff.html
+// https://opus-codec.org/docs/opusfile_api-0.7/structOpusHead.html
+
+export var parseOpusHead = function parseOpusHead(bytes) {
+  var view = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
+  var version = view.getUint8(0); // version 0, from mp4, does not use littleEndian.
+
+  var littleEndian = version !== 0;
+  var config = {
+    version: version,
+    channels: view.getUint8(1),
+    preSkip: view.getUint16(2, littleEndian),
+    sampleRate: view.getUint32(4, littleEndian),
+    outputGain: view.getUint16(8, littleEndian),
+    channelMappingFamily: view.getUint8(10)
+  };
+
+  if (config.channelMappingFamily > 0 && bytes.length > 10) {
+    config.streamCount = view.getUint8(11);
+    config.twoChannelStreamCount = view.getUint8(12);
+    config.channelMapping = [];
+
+    for (var c = 0; c < config.channels; c++) {
+      config.channelMapping.push(view.getUint8(13 + c));
+    }
+  }
+
+  return config;
+};
+export var setOpusHead = function setOpusHead(config) {
+  var size = config.channelMappingFamily <= 0 ? 11 : 12 + config.channels;
+  var view = new DataView(new ArrayBuffer(size));
+  var littleEndian = config.version !== 0;
+  view.setUint8(0, config.version);
+  view.setUint8(1, config.channels);
+  view.setUint16(2, config.preSkip, littleEndian);
+  view.setUint32(4, config.sampleRate, littleEndian);
+  view.setUint16(8, config.outputGain, littleEndian);
+  view.setUint8(10, config.channelMappingFamily);
+
+  if (config.channelMappingFamily > 0) {
+    view.setUint8(11, config.streamCount);
+    config.channelMapping.foreach(function (cm, i) {
+      view.setUint8(12 + i, cm);
+    });
+  }
+
+  return new Uint8Array(view.buffer);
+};