YouTube uses a widescreen format to display videos. One downside of this format is that it may create a black border around videos that you upload to the site, especially older videos. Fortunately, YouTube provides a way for you to alter the dimensions of your video‘s aspect ratio to fit this format. You can add a code to your video’s tags instructing YouTube to modify the dimensions to better fit the site’s format. You must edit your existing videos from the YouTube website to change their dimensions.
1. Open a Web browser and navigate to the YouTube.com website. Log in to your account.
2. Click the arrow next to your name in the upper right corner and click “Videos.” This will take you to a list of your videos.
3. Click “Edit” next to the video that you want to change.
4. Highlight the following string of code with your mouse, right-click and then select “Copy” from the context menu:
yt:stretch=4:3 yt:crop=16:9 yt:quality=high
5. Right-click in the “Tags” text box for your window and select “Paste.”
6. Click the “Save Changes” button at the bottom of your video. This will change the dimensions of your video to fit YouTube’s widescreen aspect ratio.