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DRM Reduces MP3 Player Battery Life

by March 19, 2006

A study recently demonstrated that playing back MP3 and WMA files encoded with DRM (digital rights management) copy protection can reduce battery life up to 25% .

One of the most important factors when you're thinking about buying an MP3 player is battery life. This is usually quantified in number of hours the manufacturer promises the device can play back music from a single charge.

"Rechargeable lithium-ion battery provides up to 12 hours of playback"

This is a typical specification found on a hard drive-based MP3 players today. Recent testing by Cnet found most manufacurers' battery life spec is met or exceeded when measured under optimal conditions. These conditions include using only 128kbps MP3s (no video or images) using included earbuds at 50% to 75% volume, playing in just one or two sessions with no DSP or EQ settings activated and backlighting off within 2 - 5 seconds.

Every time you search for music, populate playlists, advance track, stop / start or use larger headphones your player works harder and will reduce the charge below spec. Rechargeable batteries only have a finite number of charge cycles before they must be replaced. For MP3 players with non-removable batteries (like Apple's iPod) losing your battery means shipping back to the manufacturer for a costly replacement.

One of the surprising finds in Cnet's study was the added strain that playing back MP3s with DRM encoding had on the battery. Creative's Zen Vision: M is a critically acclaimed MP3 player that exceeded the manufacturer's 14 hour rating by 2 hours in independent testing under optimal conditions. But playing back DRM encoded WMA files downloaded from an online music service reduced the charge to only 12 hours. Similar results were found for many popular MP3 player models.

The problem is associated with the extra processing power required to decode copy protection. The worst offenders are the online subscription services like Napster and Yahoo Music that give you access to their entire library of music as long as you're subscribed. They allow you to download WMA files encoded in Microsoft's DRM 10 known as PlaysForSure. The rented music tracks check to ensure the renter's license is valid and the track is being played back on a valid (PlaysForSure compatible) device. It's an effective but power hungry way to distribute music legally and it will drain up to 25% of your battery's life expectancy. Apple's DRM FairPlay which encodes music downloaded from its online music service iTunes is also an extra drain. When your iPod plays back FairPlay music tracks, battery life expectancy will drop by about 8%. That's not as bad as PlaysForSure but certainly a consideration when you're looking for maximum battery life expectancy.

Special Thanks to www.gizmocafe.com

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About the author:

Wayde is a tech-writer and content marketing consultant in Canada s tech hub Waterloo, Ontario and Editorialist for Audioholics.com. He's a big hockey fan as you'd expect from a Canadian. Wayde is also US Army veteran, but his favorite title is just "Dad".

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