Can someone suggest settings for compressing 64K streaming audio? The aound quality is very good but I wonder about the frequency content at the high end. I want a quality mp3 file but would like a reasonable limit on size.

Should I be using a lower frequency limit (say 15Khz) during compression?
Can I sample at 32Khz without loss on the uncompressed signal and not affect the compressed audio?

Please educate me on compressing this type of source. Any help appreciated.

Thanks

If you mean that you want to encode in order to stream 64k audio, then the answer would probably be "lame --alt-preset 64"

I am capturing streaming audio (streamed at 64K) to a wav file and the converting it to an mp3 file. So I have two issues:

Can I capture to wav at 32Khz instead of 44Khz and retain a good audio file

What settings are reasonable in Lame for a quality VBR mp3 but of course minimizing size

Thanks

You would have to use another MP3 encoder since LAME doesn't support IS (intensity stereo, very important at low bitrates). I don't know exactly, but I think QDesign2 is a good encoder for this matter.

QDesign 2 can only be played back using Quicktime or that MVP player. You may want to use a more flexible solution.

I would use ogg vorbis to compress anything below 128kbps. It's just the best low bitrate solution at the moment.

MINz

Yes, I agree with you MINz. Ogg Vorbis delivers higher quality at that bitrate and it's more avaible.

im setting a mp3 stream radio (web based).

at 24 kbps-8khz- cbr-preset

im using:
--alt-preset cbr 24

24kbit 8000Hz Joint Stereo

im doing some tests with 24 kbit / 22khz and 11lhz

any knows what settings are "--alt-preset cbr 24 " ?

(im not using ogg cause most of my users
just have basic winamp - without ogg support)

guilherme moura.
http://www.reciferock.com.br

-mm --resample 32 -b64 -h --nspsytune --athtype 2 --ns-bass -8 --substep 5 --lowpass 15.5 --scale .86 -X 0,4 -Z 1

This has worked the best so far for me. I believe it requires version 3.93.1 but I may be wrong.

You can get an MP3Pro encoder from here http://www.mp3prozone.com It will sound better than lame at 64k

for compatibility, highly recommend MP3. but Windows Media Audio can do better jop at low bitrate.

beside, Microsoft already preinstall (force) windows media technology in most their OS. so if your audiences are mostly windows OS user, Windows Media is recommended.

This simply isn't true.

While Ogg Vorbis is pretty good at lower bitrates, it's certainly not the absolute best. MP3Pro is equal to or better than Ogg Vorbis, and AAC-HE (SBR) definitely outperforms it.

The differences between Ogg & mp3pro are negligible, imo. (no, I haven't ABX'd them yet, I just can't select a clear winner). I do realize that blind tests have been conducted and have generally shown mp3pro as being slightly superior to Ogg in a majority (50+%) of the samples tested. For the average listener, though, the differences in sound quality can't easily be detected. That is my half-baked conclusion, anyway. B)

MP3 @ 96k sounds like ... don't even try anything below this (especially with LAME). Vorbis is just meant to be streamed at low bitrates B)

Yeah, MP3Pro and AAC+ are nice but only difference I hear is the "sound" of vacuum in my moneybook

I have no idea whether most of the posters here really know what they are talking about or whether they are regurgiating erroneous nonsense.


i did a simple test of lame 3.90.3:

--alt-preset cbr 80

vs

LordofStars setting above for Lame 3.93.1 modified to 80kbps @ 38khz as:

-mm --resample 38 -b80 -h --nspsytune --athtype 2 --ns-bass -8 --substep 5 --lowpass 15.5 --scale .86 -X 0,4 -Z

and LordofStars setting is 10 times better for dance music.

I am going to do some comparisons on AAC at the same bitrate but otherwise for streaming dance music radio at mid-level bandwidth we have a winner...

Thank you LordofStars.


now onto lo-bandwith...


ps. mp3pro sounds totally artificial @ 80kbps with the same source. not my bag at all...

Hash
www.samurai.fm - new music radio from Japan

Wasn't it the hiss that betrayed Ogg Vorbis since ver. 1.0 used in blind listening tests?

Several other artifacts betrayed Vorbis.