How to use ffmpeg commands in heroku

Question

I've created a mp4 to mp3 converter with python using ffmpeg. It works well in my local windows pc. Now I need to host it in heroku as a web app. But the problem is, my app uses usual ffmpeg commands with os module. for example,

os.system(ffmpeg -i video.mp4 -acodec copy audio.mp3)

So I need to know if tried to run this script in heroku will it work as usual. I'm aware I can use ffmpeg in heroku as a buildpack. But I don't know wheather it works with usual windows ffmpeg commands or not.

I know I can test if it works by deploying my app in heroku, but the app is not completely developed. It has many more features rather than converting videos. So I need to know this before I further develop this project with usual ffmpeg commands.