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How is power measured "at the crank" as opposed to "at the wheel"?

How is power measured "at the crank" as opposed to "at the wheel"? I know at the wheel power and torque is measured by rolling roads, dynos, how is at the crank power measured? Is measuring power at the crank more complex/needs more expensive complex machinery thats why motoring magazines never measure it? Or is at the crank power/torque measurements not useful due to drivetrain power/torque thats why none of the motoring media measure it and use manufacturers "claimed" outputs instead of measuring at the crank power instead?
All traditional dynos, what you put your car on measure at wheels/hubs, and calculate a flywheel figure.

This calc is usually a bit **** (It's transmission loss) and can be fudged.

The other way is to take engine out the car and dyno it. Not worth it on a standard road car really.
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Murlis
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Hsv, the way they calculate it is to do the speed run on the dyno in 4th gear, and then measure the amount of friction on the wheels when the car is returning to idle revs, off throttle, this is based on the loose assumption that if there was no friction in the wheels, drivetrain or flywheel, the car would essentially slow down a lot quicker, as less resistance would allow the engine to return to idle sooner (think how quick it goes to idle when you drop the clutch) they work out the difference in power by seeing how much that is retarded.

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