![](https://hexbear.net/pictrs/image/d80b0fff-5227-4bdc-b0f6-684e985f3201.png)
![](https://lemmy.kde.social/pictrs/image/19e6d51f-5131-409e-8990-827d3d29e4d3.png)
You can just use MKVToolNix to add the second track to the MKV file after rendering, it’s still another step but doesn’t require re-encoding.
If you’re just trying to multiplex tracks and not actually edit the video, I’d recommend doing it entirely with MKVToolNix and skipping Kdenlive for this use. I’ve done this previously to combine a subbed video and a dubbed one into one file, you can offset or stretch the audio if needed as well.
Soulseek