Comments on: DRM shortens battery life by 25%

By: Morgan

Morgan — Fri, 17 Mar 2006 01:12:40 +0000

Sure. But doesn’t this study sound a little strange to you? Why evaluate the impact on the platform that constitutes, at most, 10% of the market? If it only shortens battery life by 5% on an iPod, then I don’t really care. A cold day can do more than that.

By: Chris

Chris — Thu, 16 Mar 2006 23:29:44 +0000

I don’t think you can transfer results either, but logic dictates decryption = CPU overhead = battery drain. So snip “by 25%” from the title if it makes you happy.

By: Morgan

Morgan — Thu, 16 Mar 2006 22:32:38 +0000

Still, I don’t think you can just transfer the results from one platform to the other. It’s possible that Microsoft or the hardware maker(s) just got it wrong, and Apple didn’t. I suppose it’s also possible that Apple’s actually worse. Did CNet not have access to iPods for testing? Or were the WMA results just more compelling?

By: Chris

Chris — Thu, 16 Mar 2006 22:23:00 +0000

It has to decrypt the packaged AAC stream. That’s the entire overhead. All the additional DRM rights management have little to do with processing power. The CPU load goes into decrypting the stream.

By: Morgan

Morgan — Thu, 16 Mar 2006 22:20:34 +0000

Right. But it doesn’t have anything to do with number of plays, dates, or anything like that. All it checks is is it authorized to play on that iPod. No math.

By: Chris

Chris — Thu, 16 Mar 2006 22:11:09 +0000

FairPlay content is absolutely decrypted on the iPod.

By: Morgan

Morgan — Thu, 16 Mar 2006 22:06:01 +0000

I hate to be a pedant, but the results of tests decrypting WMA DRM can’t really be applied to iTunes. Because Fair Play is essentially binary with respect to playback (can this file be played on this machine or not), I wouldn’t be surprised to learn that it doesn’t hurt battery life anywhere near as much (if at all).