Can I use AudioCapture in HTML5?

Hello.
I have a project in 4.23, intended for packaging for HTML5.

I have set up a simple Audio Capture blueprint, which captures the mic audio and then plays it back (also saving to wav file). It works fine in Play Mode, and when launching on the PC, but it does not work in the browser. Is this not possible, or is there something else I need to do to get this working?

Note: There are no errors present, and the keypresses to run the script are working, as I have text printed to screen when activating/finishing the recording operations.

Thanks in advance.

UPDATE:
I do get these warnings in the browser console window that may point to the issue:
[2020.07.25-08.04.39:308][160]LogALAudio: Warning: ALSoundBuffer wave ‘Synth’ has an invalid decompression type 5.
f00dd2b3-e801-4e18-a30e-7253f7fac7f2:13997:12
[2020.07.25-08.04.39:308][160]LogALAudio: Warning: ALSoundBuffer init failed for wave ‘Synth’, decompression type 5.
f00dd2b3-e801-4e18-a30e-7253f7fac7f2:13997:12
[2020.07.25-08.04.39:308][160]LogALAudio: Warning: Failed to initialize sound source with WaveInstance ‘Synth’.
f00dd2b3-e801-4e18-a30e-7253f7fac7f2:13997:12
[2020.07.25-08.04.39:308][160]LogALAudio: Warning: SampleRate 0
f00dd2b3-e801-4e18-a30e-7253f7fac7f2:13997:12
[2020.07.25-08.04.39:308][160]LogALAudio: Warning: Channels 1