Setting of format, mix_rate and stereo flag on mic_record

[goatchurchprime]

Which demo project is affected:
godot-demo-projects/audio/mic_record

Description:
The demo and instructions show how to print out the format, mix_rate and stereo flags, but not how to set any of them.

The AudioStreamSample class has a format option FORMAT_IMA_ADPCM, which would compress the signal. Even being able to set the stereo flag to false would save 50% of the bandwidth, as it's generally not relevant when you have a single microphone and therefore should be part of the example.

(If there is no way to set these values, maybe this issue should be filed with the core system.)

[voylin]

Whilst working on this, I found that setting stereo to false makes the length of the file longer + make the sound a lot heavier sounding.
I'll be trying to tackle this issue, changing the mix-rate is working properly.
The things I still want to do are:

• Adding a format option;
• Changing the ui to have a clearer overview of the settings;
• Fix the stereo off issue.

I expect to finish this soon (1-2 days).

[voylin]

Sorry for all the commits and closed pull requests, had a difficult time figuring out how to squash and how to make sure the format was correct. ^^"

Everything fixed now and #711 has the features as requested. Made it in the 4.0-dev branch as that's what I am currently running.

[aaronfranke]

Fixed by #711 for Godot 4.0. Thanks for the bug report!