The quality of your Broadband video streaming is based upon many factors. One factor is the Broadband service package of which you are subscribed. Most Over-the-top(OTT) video streaming companies have minimum bandwidth requirements for their particular service to function at an acceptable viewer level depending on the video quality(SD,HD, 4K or Ultra HD). Their support page or FAQ site should have this information.
This article, Speed or Bandwidth of my Broadband/Internet Connection will explain how to get the most out of your current bandwidth.
Here are a few of the popular streaming sites and their related bandwidth recommendations or requirements.
Additional factors that might cause buffering while streaming can be found in this article , Why do I have problems streaming my favorite show?