如何在web midi api中发现midi键盘？ [英] How to discover midi keyboard in web midi api?

问题描述

参考： 2013年浏览器与Web MIDI API？

目前，我正在OS 10.9.2上运行Chrome 34.0.1847.116并尝试使用Web Midi API。启用chrome：// flags /＃enable-web-midi后，我可以通过粘贴以下代码来获取midiAccess对象： http://www.w3.org/TR/webmidi/ 进入DevTools控制台。

I'm currently running Chrome 34.0.1847.116 on OS 10.9.2 and experimenting with the Web Midi API. After enabling chrome://flags/#enable-web-midi, I'm able to get a midiAccess object by pasting the following code from http://www.w3.org/TR/webmidi/ into the DevTools console.

var midi = null;  // global MIDIAccess object

function onMIDISuccess( midiAccess ) {
  console.log( "MIDI ready!" );
  midi = midiAccess;  // store in the global (in real usage, would probably keep in an object instance)
}
function onMIDIFailure(msg) {
console.log( "Failed to get MIDI access - " + msg );
}
navigator.requestMIDIAccess().then( onMIDISuccess, onMIDIFailure );

当我查询midi.inputs（）和midi.outputs（）时，返回的列表仅包含IAC总线设备。我的midi键盘（连接Turtle Beach USB midi适配器）没有出现。在试图诊断问题时，我到目前为止发现了以下内容：

When I query midi.inputs() and midi.outputs(), the returned list contains only IAC Bus devices. My midi keyboard (connected with a Turtle Beach USB midi adapter) does not show up. In trying to diagnose the problem, I've so far found the following:

• 适配器在OS X的Audio / Midi安装程序中可见并且键盘可以正确使用Logic Pro以及自制CoreMidi代码。


• Web合成器示例 http://webaudiodemos.appspot.com/monosynth/index.html 也无法找到键盘，并且在按键时不发声。


• http://djazz.se/lab/synth/当我点击它的虚拟键时会发出声音。 DevTools显示它使用的是IAC总线设备。

• The adapter is visible in OS X's Audio/Midi Setup and the keyboard works correctly with Logic Pro as well as with homebrew CoreMidi code.
• The web synth example at http://webaudiodemos.appspot.com/monosynth/index.html also fails to find the keyboard and does not make sound when keys are pressed.
• The web synth example at http://djazz.se/lab/synth/ does make sound when I click on its virtual keys. DevTools shows that it's using an IAC Bus device.

我需要做些什么来帮助Chrome找到非IAC MIDI设备？ / p>

What do I need to do to help Chrome find non-IAC MIDI devices?

推荐答案

开发人员cwilso对问题的解答（下面链接）解释了这个问题。必须重新启动浏览器以检测新的连接设备（即使已启用web-midi）。这样做会导致我的适配器被检测到并作为输入设备使用

The answer to the question (linked below) from developer cwilso explains the problem. The browser has to be rebooted to detect new connected devices (even if web-midi is already enabled). Doing caused my adapter to be detected and available as an input device

检测是否在Web MIDI API中连接了MIDI接口

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