Record audio in the browser

I need to record audio in the browser
What do we need?
PCM
16 kHz
16 bit signed integers
mono
raw wav file = has headers before data, and meta data after data

it is required to support deepspeech voice recognition engine on a server.
the code will convert audio from the browser captured with GetUserMedia().
It will convert the audio to the format above and create a blob, to send to the server.
The front end UI and most of the code base is pre-prepared.
The only need is to capture the audio in the correct form.
The code may be provided as functions, or a class, and must work for all modern browsers (Edge, Chrome, FF, Opera, Samsung)

Access to the test server which serves the webapp frontend, will be by ssh, provided if required.
The code can of course be supplied as a standalone js file.
The timeframe is 2 weeks.
Estimated work to complete - 1 DAY.
We will talk first so I can walk you through what we have in more detail, and answer any questions you have.