Youtube video quality differs depending on browser?

[Akatsuki1423]

When browsing a video on Chrome, there are only 2 quality options:
360p and 720p (the 720p seems like it's the same as 360p though...)

When browsing a video on Opera, there are more quality options, it even includes:
480p, 720p60fps and 1080p60fps

When browsing a video on Firefox, it has the same quality options as Opera.
480p, 720p60fps and 1080p60fps, etc...

This only happens for some videos, what's going on?

 

[basroil]

Yes and no, it just happens that the video is VP8 for Chome and H264 for the rest. Change your user string to firefox and they will likely show up

 

[Akatsuki1423]

Can you elaborate more on how to do that please? Thank you.