I'm using FB2k and Lame 3.97 b2 to encode several files to see if I can tell much of a difference(I'm looking to use lower bitrates to save space without a noticeable drop in quality), and something seems wrong.

When I use -V4 the bitrates seem to average around 150 or so, with -V3 it's around 160-165, and with -V2 it jumps up to 225 (these are average bitrates for 7 files from 7 different albums). Why the huge difference in bitrates between V2 and V3? Is there any VBR setting that will give me bitrates somewhere between those 2?

-v3 is between the former preset medium and preset standard so there's really nothing else in between. just decide if the quality loss is worth it or not.

It's not really quality loss. Look up / search on sfb21 bloating

Thanks!! I added -Y and now -V2 is giving me the bitrates I was aiming for and so far I can't ABX with the accuracy I getting before(I guess that means I'm finally getting older). Of course I'll try a few more times, but so far so good.

that's strange. I encode my files using Lame 3.97b2 and -V2 --vbr-new and I get an average bitrate of ~190kbps. I've just looked at 200 files from many different albums, genres and release dates...

well preset medium was not really designed to be transparent. if one can't hear a difference with sfb21 enabled then by all means use it. but for those with good ears not coding anything over 16 kHz would amount to quality loss.

-Y is not a 16kHz lowpass. Read the topic I linked.

Also, note : -V 3 is not, and never was, --preset medium

@tsioc: I (and many others) would recommend "aiming" for a certain uality level, not bitrate level. That's the whole point of variable bitrate, btw. That said, I go by bitrate (partly) sometimes - read on.

The reason for the bloat with moving from -V3 to -V2 is that -V2 makes a big jump in the high-frequencies that it tries to encode. With most music, thsi doesn't bump up bitrate a lot. But with music full of high-frequency transients (e.g., heavy metal) the bitrate will often balloon. For stuff like this, I usually will encode at -V3 because *that* much bitrate gain isn't worth it to me for frequencies that I've never been able to ABX anyway.

Finally: -V4 used to be called --preset medium.

@ tsioc: As it was above said the problem lies in sfb21 bloating.
I recommend you to check out this table: Presets, bitrates and lowpass of V value
It explains it all. All in all the setting in-between the -V3 and -V2 is my favourite: -V 2 --vbr-new -Y

mmya yeah thanks but i already said that..

"-v3 is between the former preset medium and preset standard so there's really nothing else in between"

I've wondered if it would be possible to make a setting between -V5 and -V4. There is a big jump from a target of about 130 Kbps to 165 Kbps, Something around 140 Kbps or 150 Kbps target would be useful I think. Is this possible, or do the frame sizes just make it too difficult to target somewhere between 140 and 150 Kbps?

For my MP3s I use -V3 --vbr-new. I was going to use -V2 --vbr-new, but I find that -V4 --vbr-new is good enough for me, and I just use -V3 --vbr-new as a bit of insurance.

Try -V 5 --vbr-new with 3.98a4, it produces higher bitrates per -V setting than previous versions because of the --strictly-enforce-ISO switch that is now default. I get around ~150kbps with that setting.

I didn't realise they had been tweaking this in recent alphas, thanks for pointing it out.