I have a creative muvo tx fm. The manual says that it can play up to 15 hours with mp3s, and 11 with WMAs. Why is this?
It also lists, under causes of short battery life, playing high bit-rate WMA files.
Two possibile differences I can think of:
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playing different format files would cause a different amount of work for the digital sound processor.
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playing higher bit rate files would mean more activity in the memory core, the flash memory or hard drive or whatever.
Not sure how much these would add up to, but they might account for some variability at least.
Both WMA and MP3 require decoding in order to play. WMA is a more complex format, algorithmically, than MP3, and so decoding it requires more computation.
More computations = more power consumption = less battery life.
I don’t know of the specific details of why WMA is more complex, but I have a feeling that a lot of the overhead comes from the encryption Microsoft added as an anti-piracy / DRM effort.
Is all WMA encrypted?? I mean, I can put one of my own CDs into the drive and rip it as a WMA instead of an MP3, that doesn’t require any license or DRM stuff as far as I can tell.
No, the WMA format just has the option for copy protection, but you needn’t use this option when ripping a CD.