Why do youtube videos that have a song and an album cover picture always go blurry in the middle of the song?

It seems that whenever I play a youtube video of a song where the video has only a picture of the album cover, the image blurs for several seconds and goes clear again. Is there a particular reason for this? It's not just videos from one person.

inukjuak902013-11-22T05:13:21Z

Favorite Answer

Who better to answer that YouTube itself?

YouTube ''adjusts the quality of your video stream from standard definition
based on the speed of your internet connection & bandwidth.  This is why
you may notice that the quality of the video changes as you watch videos."

http://support.google.com/youtube/answer/91449
http :// support . google . com / youtube / answer / 91449