The Reasoning

The idea for this test was born after reading a CNet.com article (reposted on MP3.com) entitled, “The truth about battery life.” The story was originally linked on their front page with the title, “Does DRM suck the life out of your MP3 player?” You would think the way this was worded the editor would be testing DRM and non-DRM tracks of the same music format, to get an accurate assessment of the impact the DRM licensing-tech has on battery life, if any. This was not the case. Below is a direct quote:



Obviously, comparing battery life when using MP3’s compared to WMA-DRM files does not prove that DRM has a negative effect in that area, as MP3 and WMA are completely different audio codecs, with WMA known to require more processing power to decode. In fact, digital audio player manufacturers who list battery life for plain MP3’s and WMA’s routinely list WMA battery life at 4 hours below what they state for MP3 playback (for example, the Olympus m:robe MR100 states 12 hours of playback with MP3 and 8 with WMA), which is exactly the difference CNet’s test found between MP3 and WMA-DRM. For a comparison to actually be valid or useful, WMA’s of the same bitrate with and without DRM would need to be examined. So that’s what we did.

The Test

To ensure accurate results, testing was done with the following music tracks…

25 of my favorite Punk rock albums, ripped from CD as 160 kbps non-DRM WMA’s in Windows Media Player 10 The same 25 albums downloaded from Real’s Rhapsody To-Go music service, as 160 kbps DRM WMA’s Music was played under these conditions… All playback was done on my DRM-capable SanDisk Sansa e260, with fully charged battery Volume at 50%, screen brightness at low, backlight always on (so I could easily monitor the battery) No messing with controls after playing the first song Playback set on ‘Repeat All’, tracks were played starting from the first track listed alphabetically, to ensure songs were played in a determined order

The Results

After rigorous testing (okay, it wasn’t that rigorous, I was sipping lemonade) the following results were obtained:

Playback time with non-DRM files: 14 hours 55 minutes
Playback time with DRM files: 14 hours 30 minutes



In the assessment non-DRM’ed playback lasted about 2.8% longer than DRM’ed playback did.


The Conclusion

Using the battery life results, I think it is safe to conclude that the extra steps DRM files must go through before playback (i.e. syncing with built-in clock) do have a very small effect on battery life, but certainly not enough of an impact to be noticeable in regular use.