Few GUI quirks

[lucellent]

Is your feature request related to a problem? Please describe.

1. Why is the pitch set to 12 by default? It doesn't make sense, should be 0
2. There's no way to stop the autoplay once it starts
3. Could be useful to add a progression bar or status once the conversion is complete in the GUI, rather than looking at the CLI

Describe alternatives you've considered

About 3 - I know that once the button "Infer" is not greyed out it means the conversion is done... not unless there was an error and it failed, without looking at the CLI you wouldn't know

Additional context

No response

Code of Conduct

• [X] I agree to follow this project's Code of Conduct

Are you willing to resolve this issue by submitting a Pull Request?

• [ ] Yes, I have the time, and I know how to start.
• [ ] Yes, I have the time, but I don't know how to start. I would need guidance.
• [ ] No, I don't have the time, although I believe I could do it if I had the time...
• [ ] No, I don't have the time and I wouldn't even know how to start.