How is ultimate meter refunded?

I've noticed that with some heroes that if I die in the middle of an ultimate, sometimes I get some partial charge back, or sometimes I just get reset back to 0.

How is ultimate meter refunded exactly? Is it that, for time based ults, whatever remaining time left on the ult is refunded? But it doesn't always seem to work this way, for ults like Roadhog's Whole Hog and Bastion's: Configuration: Tank.

Solution 1:

When you activate your ultimate, it eats up your meter rapidly (the counter-clockwise spinning). If you die before the meter is spun down, you are refunded a portion of your ultimate roughly equal to how much was left in the meter when you died.

McCree has a special refund. If he cancels his ultimate (right-click), then he is refunded 50% of his ultimate charge, no matter how long into the ultimate he cancels it.

Symmetra's ult is also refunded depending on where it is when a point is captured. If it is refunded, the amount refunded is based on how many charges are left in the teleporter.