cleaned up warnings and examples

Author: nfriedly

examples/static/audio-video-deprecated/media-element-audio-stream.js

@@ -17,9 +17,6 @@ var defaults = require('defaults');
  * @see https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement
  * @see https://developer.mozilla.org/en-US/docs/Web/API/AudioContext/createScriptProcessor
  *
- * @todo: add option for whether to keep or destroy the context
- * @todo: test what happens if source has multiple channels
- *
  * @constructor
  */
 function MediaElementAudioStream(element, options) {
@@ -67,7 +64,7 @@ function MediaElementAudioStream(element, options) {
   function processAudio(e) {
     // onaudioprocess can be called at least once after we've stopped
     if (recording) {
-      // todo: interleave channels in binary mode
+      // warning: this doesn't interleave channels in binary mode
       self.push(options.objectMode ? e.inputBuffer : new Buffer(e.inputBuffer.getChannelData(0)));
     }
   }

examples/static/file-ajax.html

@@ -22,19 +22,16 @@ <h2>Output:</h2>
 <h2>Code for this demo:</h2>
 <pre><code><script style="display: block;">
 
-  // preloading the data for a smoother experience
-  var preloadTokenAndAudio = Promise.all([
-    fetch('/api/speech-to-text/token').then(function(response) {
-      return response.text();
-    }),
-    fetch('/Us_English_Broadband_Sample_1.wav').then(function(response) {
-      return response.blob();
-    })
-  ]);
-
   document.querySelector('#button').onclick = function () {
 
-      preloadTokenAndAudio.then(function (values) {
+    Promise.all([
+      fetch('/api/speech-to-text/token').then(function(response) {
+        return response.text();
+      }),
+      fetch('/Us_English_Broadband_Sample_1.wav').then(function(response) {
+        return response.blob();
+      })
+    ]).then(function (values) {
         var token = values[0];
         var file = values[1];
 

examples/static/speaker-stream-file-html.html

@@ -26,8 +26,7 @@ <h2>Code for this demo:</h2>
   document.querySelector('#button').onclick = function () {
     fetch('/api/speech-to-text/token').then(function(response) {
       return response.text();
-    }).then(function (values) {
-      var token = values[0];
+    }).then(function (token) {
 
       document.querySelector('#output').innerHTML = 'Processing. Note: it will take some time for the first results to appear.';
 

speech-to-text/recognize-stream.js

@@ -124,7 +124,6 @@ RecognizeStream.WEBSOCKET_CONNECTION_ERROR = 'WebSocket connection error';
 RecognizeStream.prototype.initialize = function() {
   var options = this.options;
 
-  // todo: apply these corrections to other methods (?)
   if (options.token && !options['watson-token']) {
     options['watson-token'] = options.token;
   }
@@ -135,7 +134,10 @@ RecognizeStream.prototype.initialize = function() {
     options['X-Watson-Learning-Opt-Out'] = options['X-WDC-PL-OPT-OUT'];
   }
 
-  var queryParams = util._extend('customization_id' in options ? pick(options, QUERY_PARAMS_ALLOWED) : {model: 'en-US_BroadbandModel'}, pick(options, QUERY_PARAMS_ALLOWED));
+  var queryParams = util._extend(
+    'customization_id' in options ? pick(options, QUERY_PARAMS_ALLOWED) : {model: 'en-US_BroadbandModel'},
+    pick(options, QUERY_PARAMS_ALLOWED)
+  );
 
   var queryString = qs.stringify(queryParams);
   var url = (options.url || 'wss://stream.watsonplatform.net/speech-to-text/api').replace(/^http/, 'ws') + '/v1/recognize?' + queryString;
@@ -329,8 +331,24 @@ RecognizeStream.prototype._write = function(chunk, encoding, callback) {
   }
 };
 
-// flow control - don't ask for more data until we've finished what we have
-// todo: see if this can be improved
+/**
+ * Flow control - don't ask for more data until we've finished what we have
+ *
+ * Notes:
+ *
+ * This limits upload speed to 100 * options.highWaterMark / second.
+ *
+ * The default highWaterMark is 16kb, so the default max upload speed is ~1.6mb/s.
+ *
+ * Microphone input provides audio at a (downsampled) rate of:
+ *   16000 samples/s * 16-bits * 1 channel = 31.25kb/s
+ * (note the bits to bytes conversion there)
+ *
+ * @private
+ * @param next
+ */
+//
+
 RecognizeStream.prototype.afterSend = function afterSend(next) {
   if (this.socket.bufferedAmount <= (this._writableState.highWaterMark || 0)) {
     process.nextTick(next);