What is the best power saving sound format? in other words wich sound format needs the fewest CPU power on the n900 de decode it?

I just tested the media player and saw that an mp3 music files uses 40~45 % of the CPU running on 250 mHz.

Is there a music format that would bring this back, say like 5~10% less, so that the usage would be 30%?

WAV lol

how much would the difference be?

I am Happy with FLAC on my sennheisers
And those few % will be unnoticeable in battery life, but you could convert and try.

Cool i bought a Sennheiser myself i bought a bluetooth mm100 and i arrived today. i hope it has good sound!

Thanks for the replies!

Any format that needs to be unpacked will take extra time in the CPU.

WAV is PCM format with a header. This is a sequence of raw samples which would not take more CPU than what it takes to write to an ordinary file.

Not using Pulse Audio would save you a lot of CPU usage but then you won't be able to control the volume as before and, depending on how things are set up, you might lose the ability to play other sounds at the same time.