Last month, I reported on a CNET test that claimed that using digital rights management (DRM)-encoded digital audio tracks would reduce the battery life of portable MP3 players by as much as 25 percent. There was just one problem: CNET compared non-DRM-encoded MP3 files with DRM-encoded WMA and Protected AAC files, causing some music fans to cry foul. A Web site called DAPReview thought the results sounded fishy, so the site performed its own tests, this time testing both non-DRM-encoded and DRM-encoded WMA files to be sure the test was fair. According to DAPReview, a small difference in battery life is noticeable. Playing non-DRM-encoded WMA files resulted in a 2.8 percent playback increase—hardly the 25 percent that CNET claimed. More important, it appears that DRM has only a negligible impact on battery life. Too bad it has such a significant impact on usability
