Pitivi poor video quality
Solution 1:
You probably just need to adjust two bunch of settings - the project settings:
and the render settings:
(With both check the audio settings as well, and when rendering select the appropriate output format and codec, then you could try the advanced settings')
Bear in mind if you make it to high quality many devices may have difficulty playing/rendering it - though rendering a HD version and using ffmpeg to make lower quality versions could work well. Also if you do test renders with smaller chunks of video means you can tweak the settings until you get the result you want, and then you can save a preset so you can use those settings later.
Using Pitivi 0.94, with everything possible related to codecs, gstreamer (see here for why) and ffmpeg installed. The manual is available here.