I spent some time on Google and Bing trying to find out more about the hardware video decoding.
I found a couple of sites that say that the Hummingbird uses Power VR VXD hardware decoding. Anandtech states that sources suspect this, others state it is a VXD core that does the job.
The only links that I can find that state the Hummingbird does not have hardware video decoding were by somebody called antiRepublicrat posting on FreeRepublic.
If it did, we'd know, because it would be in the Android drivers. This state would explain the ability of the iPhone to play video for much longer despite having a smaller battery and a higher-resolution, non-AMOLED screen compared to a Galaxy. Or it could be that the Hummingbird does have the 370, but the A4's 375 is much more efficient. I've noticed with PowerVR a small model number increase can mean a huge increase in performance.
I know Wikipedia's not the end-all for info, but this page seems to have about everything, and omits the Hummingbird having a VXD despite having extensive listings involving the VXD series.
by somebody called antiRepublicrat posting on FreeRepublic.
Well I'll be, I'm on Google! Hey, if this post gets on Google then it'll be recursive.