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formats,bitrates,and battery consumption

post #1 of 23
Thread Starter 
Hi all. as a sequel to my question in the "abx flac and mp3 files"...or something like that,I want to get specific into different formats with different bitrates and how they effect battery life of dap's.
when i used the cowon players,I had no problem using flac because the battery lasted forever,and space wasn't as issue also so i went for the best...flac.
now i have the sansa clip+ which is of a much better quality soundwise but have very low capacity battery...it lasts only a few hours playing flac files.

now to the main questions:1. I know that flac takes more battery becasue the prossecor has to work harder in order to "unzip" the file. so,will wav files require less precessing becasue they don't need any "zipping"? will it result in better battery life? how much exactly?

2. do different bitrated effect the battery consumption as well? for example:
265 mp3 vs. 320...and if they do,why exactly?
post #2 of 23
I could be totally wrong here, but isn't bitrate also an issue? Higher bitrates>more buffering>faster battery drain. Please someone enlighten us here.
post #3 of 23
Thread Starter 
Quote:
Originally Posted by zmd View Post
I could be totally wrong here, but isn't bitrate also an issue? Higher bitrates>more buffering>faster battery drain. Please someone enlighten us here.
I am also intersted to know this...I am a total ignorance in those things
post #4 of 23
From what I understand, decoding FLAC files is actually not all that computationally intensive, so FLAC is actually easier on the processor than mp3 or ogg. The flip side is that their larger size requires a lot more disk access. This is more costly on HDD based players, but I'm guessing still takes its toll on SSD devices.

Higher bit rates produce larger files, so they cost more for the same reason. There may be a computational component to that as well for some codecs (though with FLAC, and probably most lossless codecs, this likely isn't the case).
post #5 of 23
Thread Starter 
Quote:
Originally Posted by QRomo View Post
From what I understand, decoding FLAC files is actually not all that computationally intensive, so FLAC is actually easier on the processor than mp3 or ogg. The flip side is that their larger size requires a lot more disk access. This is more costly on HDD based players, but I'm guessing still takes its toll on SSD devices.

Higher bit rates produce larger files, so they cost more for the same reason. There may be a computational component to that as well for some codecs (though with FLAC, and probably most lossless codecs, this likely isn't the case).
thank you for your thoughts. it is interesting that you say that flac can be less load on the cpu than mp3 or ogg, I thought the opposite.
anyway,while it may be true, right now it is a fact that mp3 and other lossy takes less battery life, it is not by a chance that all the dap companies give the maximum time of the battery life measured by listening to mp3 128 files.

so if lossy codecs takes less battery from any reason i want to know why?
and how much more battery time exactly?
post #6 of 23
I once thought the same about FLAC, too, but it was specifically designed to be easy to decode by putting most of the computational burden on the encoding process.

Lossy codecs are better for battery life because their smaller file size results in less disk access. My FLAC encoded files are usually in the 600-900kbps range. That results in roughly 4.5-7 times the size of the same file encoded as a 128kbps mp3, and consequently 4.5-7 times the disk access on your player.

How much that affects your battery life depends on how power hungry your drive is. As I said, it's worse on HDD than flash drives, but I'm not sure by exactly how much.

It's pretty difficult to put numbers on how much your battery life will be affected. It's dependent on too many factors like the relative power consumption of the drive, cpu, display, etc, most of which aren't well known. The best you can say is that FLAC will probably consume more power on your player than mp3. To get actual numbers you'll need to test for yourself on your specific player (or search the net for others that have already done so).
post #7 of 23
Thread Starter 
thank. so the conclusion i get from this is that disk access requires more battery than processing.
well, I am asking this for my clip+ portable player which is a flash memory based and not HDD. I wonder how much battery time can i save with lossy formats in the highest quality compare to flac.
I don't want to compromise the files but the clip+ battery life is really short playing flac,which is a reall bummer.
post #8 of 23
I've never owned a flash drive based player, so I'm not much help there. You might try asking in the Portable Sources forum what other Clip+ users have experienced. I've heard the Clip+ suffers from a short battery life by today's standards, so any tips you can get to eek out a bit more life would be worthwhile.

If you're really keen, you could always test it out for yourself. Just start from a full charge and play music until the clip shuts down, noting the time elapsed. Do it once for FLAC and once with the lossy format of your choice. You'll want to keep everything consistent across the runs so that the only variable that changes is the encoding. So do them both at the same volume level and use the same set of songs. Be sure to use a long enough playlist that your clip can't fit all the songs in RAM for either format (were that to happen, the clip would only have to access the flash drive once). I'd just pick an hour long album and set it to repeat. You could even do this multiple times for each format and average the times for a more accurate result.
post #9 of 23
Thread Starter 
Quote:
Originally Posted by QRomo View Post
I've never owned a flash drive based player, so I'm not much help there. You might try asking in the Portable Sources forum what other Clip+ users have experienced. I've heard the Clip+ suffers from a short battery life by today's standards, so any tips you can get to eek out a bit more life would be worthwhile.

If you're really keen, you could always test it out for yourself. Just start from a full charge and play music until the clip shuts down, noting the time elapsed. Do it once for FLAC and once with the lossy format of your choice. You'll want to keep everything consistent across the runs so that the only variable that changes is the encoding. So do them both at the same volume level and use the same set of songs. Be sure to use a long enough playlist that your clip can't fit all the songs in RAM for either format (were that to happen, the clip would only have to access the flash drive once). I'd just pick an hour long album and set it to repeat. You could even do this multiple times for each format and average the times for a more accurate result.
thanks,I will ask in the portable forum for other tips. I thought about testing for myself except i am too damn lazy to do it...maybe some day i don't know.
post #10 of 23
Different players will have different levels of efficiency in dealing with codecs.

For Sansa clip, here are some results of a test:

Battery Test vs Bitrate Results - Sansa Clip - Welcome to SanDisk's Sansa Community

More information:

Compression formats and power consumption - Hydrogenaudio Forums


I honestly don't know why anyone is replying in this thread without studies. This is a completely testable phenomenon, and doesn't require anyone's opinion.

What I can tell you is that on your Sansa clip, FLAC files kill battery life the most, OGG files are noticeably better, and mp3s are the best by nearly twice as much. Depending on firmware upgrades since that test I've posted, results could vary. I heard they fixed up OGG decoding a bit.
post #11 of 23
All I know is that ALAC reduces my 2009 iPod Classic's battery life by about 1/3 of spec. I'm o.k. w/ that, however...
post #12 of 23
Thread Starter 
Quote:
Originally Posted by Chef View Post
Different players will have different levels of efficiency in dealing with codecs.

For Sansa clip, here are some results of a test:

Battery Test vs Bitrate Results - Sansa Clip - Welcome to SanDisk's Sansa Community

More information:

Compression formats and power consumption - Hydrogenaudio Forums


I honestly don't know why anyone is replying in this thread without studies. This is a completely testable phenomenon, and doesn't require anyone's opinion.

What I can tell you is that on your Sansa clip, FLAC files kill battery life the most, OGG files are noticeably better, and mp3s are the best by nearly twice as much. Depending on firmware upgrades since that test I've posted, results could vary. I heard they fixed up OGG decoding a bit.
thanks for the info chef, I will follow those links.
post #13 of 23
It's the bitrate that affects the battery life the most, thus why Ogg Vorbis or AAC is preferable over mp3 tbh, as both codecs offer better quality (scientifically) than mp3 at a lower bitrate. e.g. ~192kbps AAC is better than 320kbps CBR mp3.
The extra CPU cycles due to the more complex algorithms of Vorbis and AAC is very much negated by the extra bitrate required of mp3.
post #14 of 23
Thread Starter 
Quote:
Originally Posted by chinesekiwi View Post
It's the bitrate that affects the battery life the most, thus why Ogg Vorbis or AAC is preferable over mp3 tbh, as both codecs offer better quality (scientifically) than mp3 at a lower bitrate. e.g. ~192kbps AAC is better than 320kbps CBR mp3.
The extra CPU cycles due to the more complex algorithms of Vorbis and AAC is very much negated by the extra bitrate required of mp3.
thanks. is ogg works in vbr method? or can i set it to be the same bitrate all the time?
if i would go for lossy codec i would choose the best quality available,that means the highest bitrate...and I think that ogg bitrate can go higher than mp3? or so i read...
in that case would i be better choosing 320 mp3 over let's say...500 ogg?
post #15 of 23
Thread Starter 
well,I decided to go for OGG at level 10...I left it in vbr mode, I hope it is a good choice. I know that I maybe could go even lower on the Q level but I decided that i want the best quality possible. anyway,I am sure it will significantly take less battery than flac files.

EDIT: i just converted a few flac albums to ogg q10...it sounds excellent,very transparent I don't think i could ever hear a difference...at least not on my portable rig.
I am checking how much extra battery time it would give me over the flac files.
I know that q10 is really high but I wanted the closest to lossless as i can get with lossy,
but it reduced the files size to about a half of the flac files and the bitrate is also lowered to about a half (avarage of 480-500 vs 900-1000) so let's wee what the improvement will be.
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