content/test/data/media/webrtc_test_audio.js

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // Audio test utilities.
   6
   7 // Gathers |numSamples| samples at |frequency| number of times per second and
   8 // calls back |callback| with an array with numbers in the [0, 32768] range.
   9 function gatherAudioLevelSamples(peerConnection, numSamples, frequency,
  10                                  callback) {
  11   console.log('Gathering ' + numSamples + ' audio samples...');
  12   var audioLevelSamples = []
  13   var gatherSamples = setInterval(function() {
  14     peerConnection.getStats(function(response) {
  15       audioLevelSamples.push(getAudioLevelFromStats_(response));
  16       if (audioLevelSamples.length == numSamples) {
  17         console.log('Gathered all samples.');
  18         clearInterval(gatherSamples);
  19         callback(audioLevelSamples);
  20       }
  21     });
  22   }, 1000 / frequency);
  23 }
  24
  25 // Tries to identify the beep-every-second signal generated by the fake audio
  26 // media/audio/fake_audio_input_stream.cc. Fails the test if we can't see a
  27 // signal.
  28 function verifyAudioIsPlaying(samples) {
  29   var average = 0;
  30   for (var i = 0; i < samples.length; ++i)
  31     average += samples[i] / samples.length;
  32
  33   var largest = 0;
  34   for (var i = 0; i < samples.length; ++i)
  35     largest = Math.max(largest, samples[i]);
  36
  37   console.log('Average audio level: ' + average + ', largest: ' + largest);
  38
  39   // TODO(phoglund): Make a more sophisticated curve-fitting algorithm. We want
  40   // to see a number of peaks with relative silence between them. The following
  41   // seems to work fine on a nexus 7.
  42   if (average < 3000 || average > 8000)
  43     throw 'Unexpected avg audio level: got ' + average + ', expected it ' +
  44           'to be 4000 < avg < 8000.'
  45   if (largest < 25000)
  46     throw 'Too low max audio level: got ' + largest + ', expected > 30000.';
  47 }
  48
  49 // If silent (like when muted), we should get very near zero audio level.
  50 function verifyIsSilent(samples) {
  51   var average = 0;
  52   for (var i = 0; i < samples.length; ++i)
  53     average += samples[i] / samples.length;
  54
  55   console.log('Average audio level: ' + average);
  56   if (average > 10)
  57     throw 'Expected silence, but avg audio level was ' + average;
  58 }
  59
  60 /**
  61  * @private
  62  */
  63 function getAudioLevelFromStats_(response) {
  64   var reports = response.result();
  65   var audioOutputLevels = [];
  66   for (var i = 0; i < reports.length; ++i) {
  67     var report = reports[i];
  68     if (report.names().indexOf('audioOutputLevel') != -1) {
  69       audioOutputLevels.push(report.stat('audioOutputLevel'));
  70     }
  71   }
  72   // Should only be one audio level reported, otherwise we get confused.
  73   expectEquals(1, audioOutputLevels.length);
  74
  75   return audioOutputLevels[0];
  76 }