iPad screen recording sound issue

Hi!

I hope you will forgive me for posting here in regard to a semi related matter. 

I saw this video and saw how many comments there were that it worked. I have years worth of work in the form of screen recordings which I am very much trying to recover the audio on. I tried splice, and made sure ‘automatic’ was on in settings, but had no luck. I’m really hoping you might be able to help, and certainly wouldn’t mind paying for the assistance. 

I look forward to hearing back and thank you in advance for your consideration.

Phil