PDA

View Full Version : mp3 LAME | Advanced Options: Channels



VisualBraille
08-22-2008, 02:10 PM
Hello,

It would be nice if this section was added to the application's Help Menu. In the meantime, could you indicate how the Music Converter handles each option.

Thanks!
Daniel

LtData
08-22-2008, 05:49 PM
From the mp3 (Lame) help file:
Channels:

[auto] set channels to that of source, for 2 channels Joint Stereo is used.

Mono a recording with only a single channel of information. A question that is often asked Why is my 128kbps encoded Mono file, not half the size as a 128kbps encoded Stereo file? The answer is simple, to keep the Kbps rate constant, a mono file is encoded at twice the quality rate as the stereo file (Kbps measurement is for the whole recording regardless of the number of channels, so Per Channel Kbps = Kbps / Number of Channels).

Joint Stereo - luckily for stereo compression sound on the left channel is very similar to sound on the right channel, Joint Stereo takes advantage of this similarity to use the savings on the 2nd channel to give higher quality compression.

Stereo - forces separate encoding of left and right channels, only recommended when high bitrates are used.

Is this what you meant?

VisualBraille
08-30-2008, 02:40 PM
Thank you for a brief explanation. After reading the help files I noticed that not all the options for 'Channels' appear, they are:
1) Auto
2) Mono
3) Stereo
4) Joint Stereo
5) Forced Joint Stereo
6) Dual Channels

I was simply after a description of each, which I found here: http://mirror.atrpms.net/ccrma/man/man1/lame.1.html - I would expect the help files to explain every feature the program offers, which they don't.

Now my interests lie towards finding the best settings using LAME 3.97 to rip 320 kbps MP3 files. I've spent some time searching through online resources only to find that there is no definite opinion regarding 'Stereo' vs 'Joint Stereo' both camps argue each is superior to the other - although I have stumbled across more opinions that if you're using LAME than 'Joint Stereo' will offer superior quality... while using Fraunhofer encoders 'Stereo' offers better results. Furthermore some camps believe LAME is superior to Fraunhofer encoders, but there seems just as many that would disagree.

So now convinced that LAME has the advantage, mostly because it seems to be updated and improved much more often than Fraunhofer, I'm now trying to decide whether 'Joint Stereo' is to be used rather than 'Stereo'... so you have any insight to provide?

Thanks for any advice,
Daniel

bhoar
08-30-2008, 03:34 PM
Short answer: for almost all audio out there at normal bit rates, contemporary LAME works much better using Joint Stereo than any other stereo setting.

long answer: read the wiki at hydrogenaudio.org

-brendan