Can we use FFmpeg to do any additional processing?
Yes, you can. Please see our blog, where you can find information on using FFmpeg to convert recorded files to MP4.
Additionally, take a look at our documentation on Converting FLV files to MP4 via Post Processing. In that section you will find a brief overview of this topic as well as several helpful guides. Pay particular attention to Server Optimization for Post-Processing.
Revised 11/24/2020 MD