ABC iView stuttering

I have found like the ABC's online streaming video service iView useful since I joined its limited beta at the start of this year. However, I've found that the playback has been noticably jerky on my PC (Athlon XP 2500XP, Nvidia 7600GT, 1GB RAM, Flash 10). Although my 10MB/s internet link provides adequate data, the CPU is constantly pegged at 100% by the Flash video. Interestingly, the BBC's Flash service does not have this problem. So, what's the difference?

According to Beebhack the BBC's iPlayer provides Flash streams in "standard quality" using On2's VP6 codec. As with iView this causes very high CPU usage on my PC. In contrast, their "high quality" stream uses H.264, and in full-screen mode this only requires 30% of my CPU. That's an amazing improvement that I attribute without foundation to Flash 10's use of GPU hardware to accelerate the video decoding.



I haven't seen many complaints of this nature about iView, but anecdotally I know that it doesn't stress other PCs as much. My guess is that the chosen codec is not well optimised for the Athlon. Fortunately, the ABC have stated that they will be switching to H.264 as soon as they can, so I assume that I'll get much improvement when that happens.