We also created a while back codecast for my courses in c programming. I also have Linux running entirely in the browser. And the c programming language "running" fully in the browser. Everything in sync with your oral explanations.

The courses :

https://www.coursera.org/specializations/c-programming-linux

https://www.edx.org/certificates/professional-certificate/da...

I wrote a few papers to explain:

CODECAST: An Innovative Technology to Facilitate Teaching and Learning Computer Programming in a C Language Online Course

https://scholar.google.com/citations?view_op=view_citation&h...

WebLinux: a scalable in-browser and client-side Linux and IDE

https://scholar.google.com/citations?view_op=view_citation&h...

I also have a taskgrader to grade student's codes :

Teaching C Programming Interactively at Scale Using Taskgrader: an Open-source Autograder Tool

https://scholar.google.com/citations?view_op=view_citation&h...

https://codecast.wp.imt.fr/