Is there a way to use the alternative code for a thesis/dissertation in a certain thesis template?

Now that Adobe Flash is dead, I was hoping if anyone else discover a new way to embed a video in a .pdf file instead of a hyperlink to another file in LaTeX and I have come across this link:

Media9 is becoming obsolete Dec 2020. Any alternatives for embedding video/audio in LaTeX?

and used the code in this link. It works; however, the code only seems to work by itself as an individual document. I was hoping if there is a way to use the code so that it works for a thesis/dissertation separated by front and main matter.

My videos are supposed to appear in the appendix which is a separate file titled ‘AppendixH.tex’ and include the appendix in the main matter. All my appendices begins with

chapter{AppendixH title}
label{AppendixH}

...

I was hoping to embed for one of my videos using the same template, but it doesn’t work.

chapter{Animations of Wave Propagation}

label{AppendixH}

embedvideo{includegraphics[width=textwidth]{gaussian_smoothramp.png}}{gaussian_smoothramp.mp4}

and the main.tex has the code

include{Appendices/AppendixH}

with the video-embedding code in the preamble of main.tex.