Rockbox mail archiveSubject: Re: Wma to Mp3 conversion results?
Re: Wma to Mp3 conversion results?
From: Michael O'Quinn <michael_at_oquinn.info>
Date: Fri, 24 Oct 2003 22:15:10 -0700 (PDT)
On Fri, 24 Oct 2003, LoveLearn wrote:
> Lame was mentioned as an excellent Wav to Mp3 converter. Is it better
> than others? Also, what have others decided upon as the best file size
> vs. audio quality b/s conversion guideline. Unless the conversion
> software I've tried so far is worse than Lame for example, converting
> 128 Wma to 128 Mp3 generates unacceptably-obvious quality losses. Maybe
> 128 to 160 or 192 or even 256 will be required before the conversion
> process is not obvious.
> I do have good ears and my Etymotic ER-4 earphones are quite revealing.
> I'm not trying to be super critical, but the 128 to 128 has been very
> John LoveLearn
LAME is generally regarded as the best MP3 encoder, even when stacked up
against ones you have to pay for.
One advantage of LAME is that they implement VBR (Variable Bit Rate) and
JS (Joint Stereo) very well. JS in particular has gotten a bad reputation
from some commercial codecs that really squicked up the sound when JS was
used. I haven't been able to tell the difference, using LAME, between JS
and regular Stereo, except that the bitrate is lower.
VBR usually results in a tremendous savings. I always encode with VBR,
and I don't limit the maximum. if LAME decides that a particular frame
need to be encoded at 320, it'll do that (EXTREMELY rare). OTOH, if 96
will do the job, that's what it'll choose. It uses just enough bits so
that audible quality is not reduced. (That last statement is open to
rebuttal, since the conclusion IS based on subjective tests. But that's
the idea, and IMHO it works very well.) Heavy Metal Guitar take more bits
to encode accurately than, say, silence, so more bits are used.
From the things I've read on the net, I wouldn't try VBR on any other
coded, and I CERTAINLY would not use JS, except with LAME.
I would be interested to hear about other people's experiences with JS
using a current version of LAME. I have not noticed any audible artifacts
being introduced, although I haven't really been all that through in my
Received on 2003-10-25