Hey @DeadWinter22, @HR_Sweat’s response is correct. "
Your video file should be encoded directly from Unreal only, using any methods in the documentation .
The only acceptable use for post-production software will be adding audio. Though we reserve the right to ask you to provide a screen recording of running the render from Movie Render Queue.
We would prefer that participants look at the command-line encoder to add audio from within the Engine when it comes to Movie Render Queue, or add audio tracks via Sequencer. However the first option isn’t the most intuitive without supporting documentation, the only documentation that really goes deep into this is third party. With this, we decided to allow the use of post-production software ONLY for adding the audio, and we will reserve the right to ask to see a screen recording of the render within UE.