INCREASE VOLUME WHEN RECORDING VIDEO

[papacortijo]

I have a video problem that I can't solve.
It's about increasing the original volume of a video, because it's a bit low and even if you turn it up to the maximum during playback, you can hear something low.
It's not about increasing the volume at the time of playback, but recording it with the sound already increased.
I'm using VLC, which has many uses, but I don't see this one in particular.
If someone can give me a clue as to what I can do, I'd appreciate it.
With VLC or any other program. The question is to solve it.
Thank you very much.

Soy español.
¿Alguien con quien poder hablar y entenderme mejor?
No se bien como funciona el foro.
Muchas gracias.

[Rémi Denis-Courmont]

I believe that it can be done from the CLI with the audio gain filter, but realistically people would normally use audio or audio/video editor software instead.

[papacortijo]

Thanks a lot Rémi, That's what I want, if it can't be done with VLC, what software can I use to do this job?
Thanks.