Hi @rajuKumra-8221,
You can use Azure functions to run exe's like ffmpeg. We have a documentation tutorial https://learn.microsoft.com/en-us/samples/azure-samples/functions-dotnet-migrating-console-apps/run-console-apps-on-azure-functions/ that actually uses ffmpeg to demonstrate how to run executables as background jobs. Azure functions have various triggers that can be used to kicked them off for background processing. But they're not continuous. Should you want/need to go that route, you can look at implementing a webjob https://learn.microsoft.com/en-us/azure/app-service/webjobs-create under an App Service. Though here you would need to create a console app that will run the fffmpeg exe.
Regards,
Ryan