But if I have a lot of 22 KHz files that I want to encode, would:

--alt-preset standard --resample 22050 -b 64

be the best commandline to use? I know resampling to 44.1 KHz is recommended but I really want to keep the filesizes down.

Well, one problem I can see is that the nyquist on a 22,500kHz files is only ~11kHz, while --aps uses a cutoff of 19khz. You probably need to do something custom, like for instance (if you want approximately --alt-preset standard's transparency)

-V 3 -h --resample 22050 -b 64 --npsytune --lowpass 11

Course this could be improved I am sure... anyone?

Just guessing here but... How about resampling to 44.1 and then just adding --lowpass 11 to --alt-preset standard ?

I've tried using "--alt-preset standard -b 64 --lowpass 11" but there's a noticeable difference in filesize between that and the one with 22 KHz resampling.

--lowpass 11 ~ 150 kbps
--resample 22050 ~ 100 kbps
Jebus's commanlinde ~ 80 kbps

I really can't hear the difference between any of them, but that's because I have extremely crappy speakers and no headphones.

Somebody? All I really want to know is: Is --aps still the best setting if I want to encode at 22 KHz?

Or should I add some swithes or just try out a whole new commandline? I know it's designed for 44.1 KHz but if I reeeealy want to use 22 KHz?

I think the reason you are not getting any answers is that nobody really know for sure. As you say its designed for 44.1 kHz, and I don't think there has been any work done on other sampling frequencies, so there is really not much experience on this.

My bet is that resampling to 44.1 kHz and using --aps is pretty much the best (in terms of quality) you can do but I really think it is overkill so you will be wasting bits.

i've encoded some 22.050khz samples once. 22.050khz Mp3s just sound nothing like the original 22.050 samples at all, even not at higher bitrates like 128kbps. So i ended up resampling with SSRC to 44.1 and encoding with APS. The average bitrate of the files is about 160kbps. I also found out that i didn't gain much space at all (practicly nothing) by lowering the a lowpass 11, so i didn't use it.

You might also try 128kbps ABR to keep filesize down. Resampled to 44.1@ 128ABR sounds really much better than 22.050khz@64kbps. You can also try to lower ABR values. Maybe ABR 100 will do the trick as well.


You can also try ogg. I guess it would sound nice with 44.1khz@64kbps, but i never tried it myself.

I guess Magic75 is right when he says that nobody knows for sure. I've used the search function and it seems something like this has never been discussed.

Are there any specific switches included in --aps that only works on 44.1 KHz files and actually decreases quality when used on 22 KHz? If not, then I'd guess --aps would be the best setting for this sample rate.