来自javascript的麦克风音量控制

Question

I'd like to be able to control the system microphone volume from the browser.

I know that the microphone can be recorded from using Flash or Silverlight, but these don't allow control of the microphone volume. (Flash has Microphone.gain , but as its just a software multiplier, it doesn't help when the system mic volume is muted or too loud.) I suppose the mic could be modified via a Trusted Java Applet via JNI, but getting Java installed on a user's computer is hard for non-savvy users. (Not to mention the problems with getting an Applet to consistently load.)

I've heard that HTML5 will have some sort of microphone access, but whether it will allow volume control is unclear to me. At any rate, I don't think any browsers support it yet.

Are there any plugins that would allow volume control? The old Google Gears project has some AudioApi docs, though these don't seem to have made it into the actual plugin. There's also the Google Talk plugin - it seems to do some kind of gain control, but its unclear if there's an api to the plugin.

Perhaps there's a draft HTML5 implementation plugin for microphone access (like indexeddb , for example)?

Answer 1

The verdict is that it would be a security concern. There is no way the system microphone volume can be changed by a browser application unless a plugin is used, just like there is no way to change the system speaker volume. However, you can amplify or reduce the input stream in Flash or Java.