Is there a library/framework (C#, .Net) for fully compiling a video file?

Question

.NET

Hello.
There is an implemented application (WPF) that builds a video file.
Timestamps are collected for frames (from pictures) and audio. Then, based on this data, the output video (mp4) is built.
Now the process looks like this:

• - the video is collected in a separate file (FFMpeg lib)
  
• - audio is collected in a separate file (NAudio)
  
• - both files are linked into one (FFMpeg cmd)
  

I want to do the whole process in one pass.
Can anyone suggest a framework or library?
(What a liba should be able to do: draw a background into a frame, draw sprite animations over the created frame, insert and mix an audio track and effects (explosions, screams), output this entire timeline into one file at once)
Thanks for the answers!