I have a shadowplay movie, i try to use MainConcept MPEG-2 with a standard template at 25 fps, it works. I change the template to 60fps, and i get a message "an error occurred... the reason can not be determined"

I also cant render that as a .mp4 file, it just forces a .m2t file

I tried rendering with Magix AVC/AAC mp4 instead, but the quality is worse, it seems to have a clear image, but over a few seconds it becomes pixelated, then suddenly it becomes clear and starts to become worse over a few more seconds, and that just keeps going, so it looks like i have really bad bitrate, even if i set the bitrate over what the source has.

Is there a way to fix so i can render at 60 fps with main concept, or maybe somebody knows what causes the wavy quality dips.