Please note that preview area in the editor does not show actual output resolution.
After exporting, video quality will be better than in preview.
This article only applies to low quality of already exported videos.
Please also note that under "low quality" here we mean resizing of the original video and pixelisation.
There are cases when exported video or preview have visual artifacts like green or black squares, etc.
In such case please refer to another article: OpenGL-related issues
It might be that your original videos feature higher resolution than default Full HD (1920x1080) resolution.
Please make sure that your project and export resolution correspond to resolution of your original videos:
1. You may check the original resolution by right-clicking a file on the timeline and selecting File Information:
2. You can change the resolution of the whole project by clicking a [16:9] button next to preview area:
3. Make sure that the resolution is unchanged when proceeding to export:
If there are still any issues after these steps, please contact our Support Team with more details and screenshots.