Video quality is depend of few points.
First, straight after upload video is published but still sometimes need some time for youtube to convert it to resolution which you desire so it will take time sometimes even few hours.
When you are about to upload video, you can check settings for uploading video in what resolution you would like to upload it, higher resolution, longer time to upload but better quality.
For me, looks good, that's why I believe it was a first reason, youtube just took his time to make resolution on place.