I've grabbed your IPU test OPK, and ran it on my usual test videos, and have noticed that indeed the performance has not changed much:
a) Mythbusters episodes (xvid/AVI, 624x384) are still around 95% CPU to decode. They look a bit crisper with details, and are shown at close to 60 FPS, but when there are LOTS of motion vectors, it gets slower.
b) Some comedy show episodes ripped from DVDs (H.264+AAC/MPEG-4, 708x364) are decoded 5 to 7 times too slow, and the sound runs uninterrupted with highly desynced video. [edit:
N.B. these files were the results of some transcoding tests, they're files with CABAC, a constant PSNR, and shitloads of reference frames. They might not even be mobile-friendly H.264 bitstreams.]
This is all pretty close to what I got before. I bet it's motion compensation, IDCT, deblocking and colorspace conversion all still being done in software, and that's pretty expensive.
There's one thing with the IPU though, and it's that you can adjust the aspect ratio with Power+A - so if the aspect ratio is wrong in a video, the user can do something about it (provided the correct aspect ratio is 4:3). And now, if HDMI video output gets implemented, that test build can already display the video at the original resolution, and not some scaled-up version of what gets displayed on 320x240, possibly downscaled from something higher