You can fix this by adding ?vq=hd720 to the end of video src as explained in the StackOverflow answer.
Learn how to fix a video that is blurry in the preview

Written by Ilgım
Updated over a week agoLearn how to fix a video that is blurry in the preview
You can fix this by adding ?vq=hd720 to the end of video src as explained in the StackOverflow answer.