When I render a full project using the latest kdenlive I get a very bad quality video, highly pixelated.

It's still 1080p but all shots and audio look poor and a 55minute documentary is 400mb in size.

Rendering the selected zone, so still the full documentary of 55minutes gives me amazing quality, just what i'm after and an 11gb video file.

No other settings are changed, video quality set to highest (15) and MP4 video file.

So it works, took me 2 days to work this out but weird?