To preserve the source aspect ratio:
Connect to the Admin panel using your preferred connection mechanism. See Connect to the Admin panel.
- Login as admin.
- Click on your channel, then select Sources; the Sources page opens.
- At the top of the page, click the row for the layout you want to edit, then click on the relevant layout item; the Source settings box appears.
- From the Source settings box, make sure Keep aspect ratio when scaling is selected.
- Scroll to the bottom of the page and click Save.
Unstretching the image causes a matte (black bars) to appear on the sides or top and bottom of the output. To remove these see Remove black bars (matte) from the video.