Picture quality

Hello all,

I’ve just put together my first video using footage from a Gopro. I chose a preset in the export list, H.264 main profile, couldn’t see a reload button so I hit export.
Saved the video, but when I view it back the picture quality is not very good.

The Gopro was set on NTSC and not PAL.

Any Ideas what I’ve done wrong ?

I’m willing to learn but it usually takes a while to sink in.