Hi guys,

here one of those classic question,

I have an Apple iBook 600 Mhz. I use as ripper iTunes 2.0.4 and as encoder LAME 3.92 for OS X (through plug in).

The results are very good, I'm very happy with them.

I don't have "that" good hearing so using -Y is ok for me (I don't think most people can notice the difference anyway between encoding using -Y or not)

What concerns me just a bit is whether using "fast" or not. I don't have so much time to rip, my girlfriend always demand time from me and I have a lot of projects on the way, well the speed difference is really big (3 times faster?)

Is the quality difference only that slightly as been said?, Or better said, What actually does this "fast" switch do?

On most material, the difference between --aps and --aps fast should be pretty small. There are even 1 or 2 cases where it may perform better (though there are also a similar amount where it may perform worse). Over all, on an average, it's pretty close.

What happens when the fast option is used, is that vbr-mtrh gets set as the vbr mode instead of vbr-old. Some of the code level modifications for --alt-preset standard in their original form do not work with vbr-mtrh in the same manner, so some of these techniques are also altered when you specify the fast setting. The reason the fast setting is not defaulted is because a few of the modifications cannot be implemented quite as well with vbr-mtrh as with vbr-old, though, like I said, the resulting quality difference on average isn't too large.

Hi Dibrom,

First of all, thanks for the precise answer. It really helps.




I've read many of your messages here before asking any queston, and always wondered when you referred to "pretty small" difference or "pretty closed". Or better said, I wondered how do you do your hearing test? "pretty small" difference means to me, you reeeeally have to listen to the tracks at 3 o'clock in the morning (because there is less background noise) with a good $300 headphones or a veeeery good hifi system with a good pair of Speakers. There are days where music sounds different to everybody than other days. "pretty small" difference means to me, it could be even hard to notice the difference in a "blind hearing test".

Once in an american magazine (don't remember the name now) there was a very interesting article about very good written which in resume said that doing Music hearing tests is one the most difficult and subjective things in this world. The same music sound with the same equipment completely different in different places or same places at different times at what most important (at that was the key of the article) at very slightly different volumes. If you hear to music to do tests, e.g. to compare different loudspeakers, amp, players or whatever, it will always will seem to sound better the one which sounds a bit louder, even if very slightly. Practically blind tests shows that the article is right. Very well known magazine "testers" will never go to a blind test, they know their reputation would be in play and the would surely loose.

Now how can influence this subject to LAME hearing tests?, well some frecuencies coded with different settings will sound different and that mean slightly louder or slightly smoother. That something will sound different, does not necesarily means it will sound better or worst.

Please don't misunderstand me , I'm not saying here in any way that your test are not acurate, I'm using your results and I'm sure you have a very good sense for music quality and beside that an excellent programmer (rare to see). So, the question is, how do you do your hearing tests?


By the way, I'm surprise to have got your answer so soon, because in the states must be now very early in the morning.

I was wondering about the same thing many times.

My guess was that APSF wouldn't be as compressed as the APS...(less time reading frames and encoding higher bitrate to that frame)

Is there a big difference in compressed file size?

apfs uses a new vbr mode, which is faster than the old vbr mode used in aps, but is a little worst too, and the size will be incresead 5kbps - 10kbps