If you would like to force Vimeo to always serve HD videos, you'll need to have a Vimeo Plus or Pro account. Log into your Vimeo account and then click
ME > MY SETTINGS > VIDEOS > FILE SETTINGS
In the File Settings, click both:
- "Make my videos compatible with mobile devices"
- "Always play my videos in HD, when possible"
When an option opens, you can click to "Also, apply to all existing videos."
Check it, click on SAVE AS DEFAULT button.