问题
I'm using the Web Audio Api ( navigator.getUserMedia({audio: true}, function, function) ) for audio recording.
If the user has several microphone devices, can I select the desired recording device?
I've came across a problematic situation where a brand new Dell laptop (running Windows 8.1) has 2 microphone devices (on board and external) and the external device was set to default (set to default by the operation system).
As expected, when recording, the input comes from the external microphone which means - silence - no actual input.
Can I work around this technologically and capture the audio from the on board device?
While searching I found this question which talks about detecting the sound card.
From the answer:
You have no control over the latency. You have no way of detecting the actual sound device. All you can determine is if the browser gives you access to the audio channels, and how many of them. I've also found that regardless of what is on the other side, Chrome will only open up a stereo channel. (It will also treat mono devices as stereo, copying the first channel to both L and R channels.) Firefox has similar issues.
Recording devices screenshot - http://i.stack.imgur.com/jUrCw.jpg (can't add the actual photo yet)
Would appreciate suggestions.
Thanks! Avi.
回答1:
You can (select the input device) - take a look at https://webaudiodemos.appspot.com/input/index.html, which lets the user select the input. Note that you won't get access to the actual names unless you serve securely (https instead of http).
回答2:
You want to use device enumeration and a deviceid constraint. As per @cwilso's answer, https://webaudiodemos.appspot.com/input/index.html is an example that works in Chrome. If you change the default microphone in the OS, Chrome should pick it up.
Firefox is adding deviceIds and constraints, but they haven't hit release yet. Currently on firefox the user can select any audio device for input if they don't select "Allow Always" when approving (if they do, then it will select the default device without asking the user). Note that Allow Always requires loading over https, and it's not the default action (unlike Chrome).
回答3:
You can select any recording device you want with Web Audio API, look at https://jsfiddle.net/bomzj/beap6n2g/.
来源：https://stackoverflow.com/questions/31264487/web-audio-api-input-from-specific-microphone