Nextbase 622gw Video Playback Issue

[Mikeact]

Hi. Installed a new 622GW this week. On returning home from a long run ,I took a look at the video files today. Suffice to say that it was a good job that I didn't have an accident as the videos aren't good enough....certainly couldn't read any number plate. They are very jittery and not at all smooth. I am using a u3 class10 card.
Any advice appreciated. Thanks.