Dartium does not support Web Audio API

[sethladd]

The following Dart code:

import('dart:dom');

main() {

  var audioContext = new AudioContext();

  var source = audioContext.createBufferSource();
  source.connect(audioContext.destination);

  var xhr = new XMLHttpRequest();
  xhr.open("GET", "techno.mp3", true);
  xhr.responseType = "arraybuffer";
  xhr.addEventListener('load', () {
      var buffer = audioContext.createBuffer(xhr.response, false);
      source.buffer = buffer;
      source.noteOn(0);
  });
  xhr.send();

}

(which works fine in JavaScript) does not work in Dartium

Error:

Exception: NotImplementedException
Stack Trace: 0. Function: 'AudioContextImplementation._bind@1c3f8015' url: '/b/build/slave/dartium-mac-inc/build/src/xcodebuild/DerivedSources/Release/webkit/bindings/AudioContextImplementation.dart' line:61 col:3
 1. Function: 'AudioContextImplementation.AudioContextImplementation.' url: '/b/build/slave/dartium-mac-inc/build/src/xcodebuild/DerivedSources/Release/webkit/bindings/AudioContextImplementation.dart' line:57 col:15
 2. Function: '::main' url: 'http://localhost:8000/app.dart' line:5 col:20

Dartium version: 18.0.1023.0 (Developer Build 119649 Mac OS X)

See attachments for HTML and MP3

---

Attachments:
techno.mp3 (362.45 KB)
app.dart (448 Bytes)
index.html (325 Bytes)

[sethladd]

A more reduced test case, which fails in Dartium:

#import('dart:dom');

main() {

  var audioContext = new AudioContext();

  var source = audioContext.createBufferSource();
  source.connect(audioContext.destination, 0, 0);

}

error:

Exception: NotImplementedException
Stack Trace: 0. Function: 'AudioContextImplementation._bind@1c3f8015' url: '/b/build/slave/dartium-mac-inc/build/src/xcodebuild/DerivedSources/Release/webkit/bindings/AudioContextImplementation.dart' line:61 col:3
 1. Function: 'AudioContextImplementation.AudioContextImplementation.' url: '/b/build/slave/dartium-mac-inc/build/src/xcodebuild/DerivedSources/Release/webkit/bindings/AudioContextImplementation.dart' line:57 col:15
 2. Function: '::main' url: 'http://localhost:8000/app.dart' line:5 col:22

[dgrove]

Set owner to [email protected].
Added Area-Dartium, Triaged labels.

[DartBot]

This comment was originally written by [email protected]

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Seth, that apparently works fine with the most recent Dartium.

May you double check?

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Set owner to @sethladd.
Added NeedsInfo label.

[alextekartik]

It cannot be tested in Dartium yet due to issue: 1773 http://code.google.com/p/dart/issues/detail?id=1773
Currently xhr.response is not accessible (in Dartium only, fine in js) so the mp3 cannot be read

[DartBot]

This comment was originally written by [email protected]

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Closing w/ assumed stale, please, reopen if still an issue.

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Added AssumedStale label.

[alextekartik]

Below is a sample code that works in JS in Chrome but not in Dartium. It simply plays a simple generated sound. I don't know the proper way to re-open a bug...

    dom.AudioContext audioContext = new dom.AudioContext();
   
    final int SAMPLE_RATE = 44100;
    final double PI_2 = Math.PI * 2;
    final int BUFFER_SIZE = 4096;
    dom.AudioBuffer audioBuffer = audioContext.createBuffer(1, BUFFER_SIZE, SAMPLE_RATE);
    
    dom.Float32Array buf = audioBuffer.getChannelData(0);
    
    for (int i = 0; i < 4096; ++i) {
      buf[i] = Math.sin(440 * PI_2 * i / SAMPLE_RATE);
    }
    
    dom.AudioBufferSourceNode source = audioContext.createBufferSource();
    source.buffer = audioBuffer;
    source.connect(audioContext.destination, 0);
    source.noteOn(0);

In Chrome/JS we here a sound. In Dartium we get the following error:

Exception: UnsupportedOperationException: [info: ..\bindings\dart\custom\DartAudioBufferSourceNodeCustom.cpp:42]
Stack Trace: 0. Function: 'AudioBufferSourceNodeImplementation.set:buffer' url: 'e:\b\build\slave\dartium-win-full\build\src\build\Release\obj\global_intermediate\webkit\bindings\dart\dart\AudioBufferSourceNodeImplementation.dart' line:16 col:3

Tested on Windows DartEditor Build 7199 (as of 2012-05-01).

[sethladd]

Thanks Alex. Re-opened.

We are moving away from the dart:dom libraries. Can you try with dart:html?

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Added Triaged label.

[alextekartik]

Smae code using dart:html below works in Chrome/JS but failed in Dartium like for the DOM API:

Exception: UnsupportedOperationException: [info: ..\bindings\dart\custom\DartAudioBufferSourceNodeCustom.cpp:42]
Stack Trace: 0. Function: 'AudioBufferSourceNodeImplementation.set:buffer' url: 'e:\b\build\slave\dartium-win-full\build\src\build\Release\obj\global_intermediate\webkit\bindings\dart\dart\AudioBufferSourceNodeImplementation.dart' line:16 col:3
 1. Function: '[email protected]:buffer' url: 'e:\b\build\slave\dartium-win-full\build\src\build\Release\obj\global_intermediate\webkit\bindings\dart\html\dartium\AudioBufferSourceNode.dart' line:7 col:52
 
Source code:

    AudioContext audioContext = new AudioContext();
    
    final int SAMPLE_RATE = 44100;
    final double PI_2 = Math.PI * 2;
    final int BUFFER_SIZE = 4096;
    AudioBuffer audioBuffer = audioContext.createBuffer(1, BUFFER_SIZE, SAMPLE_RATE);
    
    Float32Array buf = audioBuffer.getChannelData(0);
    
    for (int i = 0; i < 4096; ++i) {
      buf[i] = Math.sin(440 * PI_2 * i / SAMPLE_RATE);
    }
    
    AudioBufferSourceNode source = audioContext.createBufferSource();
    source.buffer = audioBuffer;
    source.connect(audioContext.destination, 0);
    source.noteOn(0);

[DartBot]

This comment was originally written by [email protected]

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Alex, thanks a lot for reporting and this issue should be fixed now.

General plea: please, let's not make this issue a catch all for troubles with Audio API---it's better to file a separate issue referencing potentionally related one.

Thanks in advance!

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Set owner to [email protected].
Added Fixed label.

[alextekartik]

Great it is fixed as of build 7323. And yes I'll report API bugs one by one as I test them. I started with issue #2897 regarding AudioContext.decodeAudioData