Default [Q] How to record at a lower resolution/bitrate?

With my LG G2 (currently running CloudyG3 custom rom 1.2) I have the possibilities to record videos in:
- 120 hd slowmotion
- hd 1280x720
- fhd 1920x1080
- 60 fhd 1920x1080
- uhd 3840x2160

But all these formats take huge spaces. For example a 10 minutes video in hd 1280-720 will take almost 1 GB of space.
Is there a way to record at a lower resolution/bitrate (eg 800x600) so the file sizes are more storage-friendly?
maybe with some external camera app?