I have an 1Gbps Internet connection speed that can easily support even multiple simultaneous Full-HD (1080p) video streams. However, when I watch videos on YouTube, the 480p quality level is automatically selected.
Why don't they change the video quality automatically based on my connection speed?
UPDATE: I noticed something interesting: if I switch to YouTube's HTML5 player, then it will automatically select the 720p quality-level the moment I switch to fullscreen size.
I’m sorry to post in this old thread, but seeing as it’s at the top of Google and lots of people are asking the question on Google, I’ll provide an update. As of June 2020, Google has set the default resolution to 480p on mobile devices to combat the increased load of users working from home. It is unknown when they will switch it back.
Set the video playback settings to Always choose the best quality for my connection and player size.
YouTube automatically changes the video resolution according to the player size (as mentioned in the setting) so if you're not watching a video in full-screen, the resolution might be set to 480p. Switch to full-screen and it's HD.
If you'd rather force a 720p resolution everywhere, you might want to look into installing YouTubeCenter as @stanciupaul suggested
Maybe they though it's wrong for a desktop that uses a fast mobile Internet connection (with limited monthly quota) to select 1080p quality by default. That way, watching a few videos would make your Internet connection reach the quoata limit very fast or even drive to extra costs. Other reason may be computer's hardware performance that may not be able to run the videos in 1080p.