How does it hold up against VBR (obviously the latter is better), but just how much better for the average Joe with a pair of normal earphones? I only ask because I want to reduce file sizes for my MP3 player, and VBR uses more battery power.

VBR shouldnt use more battery power. Your best bet is to look up ABX testing, and see for yourself if you hear a difference. Which you probably won't.

Just make sure you don't transcode (look that up too, if you don't know what it is.)

I have seen a test conducted on an MP3 player site where he used a number of different music files with different encoder setting, and VBR reduced battery life significantly.

Why exactly should vbr use more battery power and which player was used for the test?

If you want smaller files, use vbr with -V 4 (or preset medium). Average bitrate should mesure in below 160kbit/s but quality should be higher.

If VBR uses more battery power than CBR, the only reason that can explain it is only that higher bitrate (i.e. a 320CBR file) uses more power than a lower bitrate one (i.e. a 128CBR file).
Reasons for this include from disk usage (in hard drive based models), to CPU usage of the decoder.

For a similar bitrate, CBR and ABR (maybe even V5 in this case), there shouldn't be *significant* power difference. Less than double.

Define "average". Define "normal".
Quantify "reduce". Quantify "more".
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In short, your results will likely vary from other people's results, so you will need to do your own testing, in order to reach a trade-off point between quality and efficiency that is right for you.

Regards,
Madrigal

If its just for a portable, why not encode to APS and transcode to 128k (or even less) for portable use? Its not like you're going to hear the difference through a typical portable with typical $5 earbuds. Not to mention the ambient noise outdoors, driving, etc. Unless you've got very good ear buds and a very quiet listening environment, 128k transcodes are probably fine.

I had an mp3 player that bogged down (meaning the music was played at 3/4 speed) on vbr files, but not cbr. It wasn't a top of the line model by any stretch of the imagination, but still...

Regarding battery usage: IF high bitrates bog down the battery life of YOUR player(read: test it before asuming), then ABR is still a way better choice than CBR. Somthing like 150kbps ABR will rarely go into the high-bitrate range.

Players which dont support VBR/ABR aren't fully mp3-compatible and can be considered broken(VBR is part of the MP3-standard)

- Lyx

I would think that you were trying to play a 48Khz file when your player only supported 44.1Khz (or any similar combination).
VBR files are no different than CBR files. It only keeps changing the size of the data to process. Only problem derivated from non-conforming VBR players is either skipping, or wrong seeking/duration. Else, the player already has problems with CBR files.

I know for a fact they were not 48Khz.