[minnesota_bound]

Have you tried “Audacity”
https://www.audacityteam.org
It is free and can boost the sound. Select the track then go on the toolbar> Effect> Amplify

The files generally have to be mp3 or other audio files.
There are free video to mp3 converters out there.

[Paul R.]

I poked around a bit with Audacity a while back. Like, maybe 15 years back! Seemed to have a pretty significant learning curve, plug-ins needed, etc. There was something more I needed to install and I never could get it right...

Wavosaur was just so much easier...

But, maybe Audacity’s coders have “decomplicated” the user interface a bit and incorporated more native functions since then?

IF I can use Wavosaur with an external (USB) Audio Interface that might give me some options / more control?

I have one of these - never got time to try it out to see what all it can do:

https://www.amazon.com/Behringer-U-Control-UCA222-Ultra-Low-Interface/dp/B0023BYDHK?pd_rd_w=CKUge&content-id=amzn1.sym.c15e5526-d433-4ac0-a393-a3f3f7218fab&pf_rd_p=c15e5526-d433-4ac0-a393-a3f3f7218fab&pf_rd_r=PF4JC8E8R8WXB4FG0TSF&pd_rd_wg=TeVUA&pd_rd_r=426001fc-9d9d-4218-a15d-5c961c7a6c4c&pd_rd_i=B0023BYDHK&psc=1&ref_=pd_bap_d_grid_rp_0_1_ec_t

:-(