Ill make this as quick as possible. I recorded with obs, used ffmpeg to convert from .mkv to .mp4 with 3 audio tracks in .aac
@echo off & setlocal enabledelayedexpansion for %%v in ("*.mkv") do ( set FileName=%%v set name=!FileName:~0,-4! set outname=C:\Users\Ashto\Videos\actual obs\!name! echo Remuxing: !name! to !outname! ffmpeg -i "!FileName!" -map 0:v -c copy "!outname!.mp4" -map 0:a:0 -c copy "!outname!_0.aac" -map 0:a:1 -c copy "!outname!_1.aac" -map 0:a:2 -c copy "!outname!_2.aac" ) pause
After doing this, for the first bit of footage I got a video output of 24:31, which was correct. However the first audio track was 23:04, the second audio track was almost 12 hours (it was just looped) and the 3rd was 24:39. The second bit of footage wasn't as extreme, however the 3rd audio track for it was missing 10 minutes of audio. If anyone knows why, I would love to know.