How does a frog separate blood in its ventricle?

Since a frog has two atria and one ventricle, how does it separate oxygenated blood from deoxygenated blood when both are mixed in the ventricle? Or does a frog simply pump a mixture of both to the heart and the lungs? I checked a few videos and sites for this, but was unable to find an answer.

https://www.youtube.com/watch?v=MhOCzvA4KhM&ab_channel=iWorxSystems%2CInc.

My best guess, based on the above linked simulation, is that it has to do with a difference in densities of oxygenated and deoxygenated blood, but I am not sure.