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 exported videos.
Also note that 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 the original video features a higher resolution than default Full HD (1920x1080) resolution.
Make sure that your project and export resolution correspond to the resolution and bitrate of your original videos:
1. Check the original resolution and bitrate by right-clicking a file on the timeline, and select File Information:
2. Adjust to match 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. Apply the same bitrate for the resulted video:
If the output quality still doesn't match the original, please, contact our Support Team, and provide us with the input and output video for further investigation.