{center}
{subhead}LAME 3.86{def}{p}
Review by Robert Karlsson
{left}
{p} {p}
MP3 should be a familiar term to everyone that uses a computer these
days, but just in case someone out there have been living in a cave
somewhere and even then mysteriously enough been able to avoid
getting bombarded by medias extreme focusing on this whole thing, I
will go through a little the basics of what an MP3 file is, and a
little about how it works. I am merely a layman myself, so there's
bound to be heaps of mistakes everywhere, but here we go; MPEG 3
(Moving Picture Experts Group), is a widespread standard for audial
and visual information. We are going to focus on MPEG Audio Layer 3,
or MP3 for short.
{p} {p}
There are tons of technical terms and information which I don't even
want to begin to understand, so I'll try to keep it plain and simple.
Basically, what happens when you encode an uncompressed audio file,
such as an AIFF file, is that the encoder cuts off the parts and bits
we're not supposed to hear and but the remainders back together, and
out comes this marvelous little thing that is making the music
industry tear their hair off when they see their precious money being
taken from them because of this extraordinary phenomenom. This works
generally quite well, unless you're really picky about sound quality,
have no soundcard or you are still using your monitor for the audio.
{p} {p}
The bitrate is something that is causing a little confusion also
among people that have discovered this thing with MP3, and also among
the manufacturers of MP3 encoding software; but it seems to be the
general publics conception that 128 Kbit stereo MP3's are equivalent
to CD-quality - whether this is true or not can be discussed, I
personally think that 128 Kbit encoded MP3's are crap and hardly
worth the trouble of making, I prefer 192+ Kbit encoded MP3's, but
since it doesn't really matter in time aspects I have performed the
test encoding with the standard 128 Kbit setting in the program this
review is about, namely LAME (Lame Ain't An MP3 Encoder), which is a
LGPL (Gnu Lesser Public License) freeware software product for not
only the Amiga, but also for a large amount of other platforms as
well.
{p} {p}
The program is based on the sources released by the ISO-group, a
german team of developers (if my memory isn't playing tricks on me),
and from thereon heavilly modified, so much that all remnants of the
original sources are supposedly gone and replaced for quite some
time. What you get when you extract all the contents of the LAME
archive are a bunch of files, the executables, the manual and
descriptions, an ARexx script for multiple encodings, and a neat
little program called LAMEspin, this is a patch to make the LAME
executable of your choice work together with a CD-ripping program
called SecondSpin. There's also a program called sfplay and
accompanying libraries...
{p} {p}
First, let's have a look at the "USAGE" manual. It's easilly
structured, with heaps of examples with the basic commands first and
then a "operational guide" for each and every of the commands
available. You can't go wrong, even if you have minimal experience
using Shell you shouldn't have too much trouble getting it up and
running (there are some GUI's and scripts that handles it
automatically on the Aminet if you should experience troubles,
there's also the previously mentioned SecondSpin which can be a good
alternative if you are having troubles or are just too lazy to fiddle
about with it in the command line). I see no point in going through
every single command, as they are well documented, so I'll just go
through the most important ones you need to know.
{p} {p}
The easiest way to test LAME is just to DIR into the drawer where you
have put LAME, and then write someting along the lines of "lame
work:uncompressed_song.aiff mp3_song.mp3" this will make LAME process
the file "uncompressed_song.aiff" with its default settings and store
the MP3 file in the same directory as LAME (if you don't give the MP3
a name, LAME renames it to the sample's name and adds the .mp3
extension and stores it in the same directory as the original
sample), in this case it would be "Program:". This is a quick and
easy way to try it out, but if you want to get a little more out of
the results you should use a switch called "-h" in the commandline.
"h" stands for High, and what it does is that it raises the quality
of the encoding, it's also a little bit slower, but not slow enough
to be annoying, if you ask me. This works like a charm, here are the
speed results of my encoding of a 34.419.222 (3:15 minutes long)
bytes large AIFF file, with the default mode (128 Kbit, J-stereo):
{p} {p}
Frame                    |   CPU/estimated |  time/estimated | play/CPU | ETA{p}
7394/  7394 (100%) | 0:16:12/ 0:16:12| 0:16:12/ 0:16:12|    0.2008| 0:00:00{p}
{p} {p}
I case this didn't make any sense at all, then plain and simply just
how long it took, i.e roughly 16 minutes, the frames being
processed/percentage of the encoding done, etc...
{p} {p}
And here are the results of the encoding from the same file, but with
the "-h" switch enabled (128 Kbit, J-stereo):
{p} {p}
Frame                    |   CPU/estimated |  time/estimated | play/CPU |  ETA{p}
7394/  7394 (100%) | 0:17:57/ 0:17:57| 0:17:56/ 0:17:56|    0.1794|  0:00:00{p}
{p} {p}
Higher quality, and about two minutes more waiting. Perfectly
acceptable for me at least.
{p} {p}
You probably noticed that strange word "J-stereo", didn't you? Well,
this is form of stereo is actually called MS-Stereo, which stands for
Mid/Side Stereo, why it is also refered to as Joint-stereo (J-stereo)
is because it sort of "joins together" the two stereo channels, and
in some way or another the results gets better on lower bitrates,
such as 128 Kbit encoded MP3's. On higher bitrates, such as 192+ Kbit
it is pointless to use the Mid/side technique, because the stereo
signals are high enough anyway.
{p} {p}
Now, let's go through another nice feature of LAME, the VBR (Variable
Bit Rate) setting (on the two earlier encodings I used CBR, which
stands for Constant Bit Rate - with constant bitrate you use the same
encoding technique on all frames of the sample). When you use the VBR
you can choose between using it with the default switch (-v), all you
do then is set which bitrate you want to use whilst encoding. The
manual recomends 112 Kbps, so that's the bitrate I specified in the
test below. Here are the commandline options used for the test below:
"lame -v -V 0 -b 112 -B 192 program:uncompressed_song.aiff
mp3song.mp3"
{p} {p}
Encoding as 44.1 kHz VBR(q=0) stereo MPEG1 LayerIII ( 5.0x estimated)
qval=2
{p} {p}
Frame                    |  CPU/estimated  |  time/estimated | play/CPU | ETA{p}
7470/  7470(100%)  | 0:49:12/ 0:49:12| 0:49:12/ 0:49:12|    0.0661| 0:00:00{p}
 32[  0%]{p}
 40[  0%]{p}
 48[  0%]{p}
 56[  0%]{p}
 64[  0%]{p}
 80[  0%]{p}
 96[  0%]{p}
112[  0%]{p}
128[  0%]{p}
160[  0%]*{p}
192[ 99%]**************************************************{p}
224[  0%]{p}
256[  0%]{p}
320[  0%]{p}
average: 192 kbs{p}
{p} {p}
Now, let me explain what I did onthe commandline. First of all, I set
the VBR option with the "-v", then I set the quality with the "-V"
option, the quality in this case was 0, as this is the highest
possible setting for VBR. I then specified the smallest allowed
bitrate with the "-b", being 112 Kbps and the highest allowed being
set with the "-B" switch, which in this case were 192 Kbps. See, now
that wasn't so difficult, was it? If you still think so, then there's
a default option, which you set with only "lame -v -b n" (n = number
of bitrate), and the encoder itself will do the rest. Unfortunately
this version of LAME for the Amiga seems to crash when doing that, so
I wouldn't recomend it with this version.
{p} {p}
Why is VBR good then? You might ask. Well, the easiest way of putting
it would be to say that with VBR you basically get a little higher
quality and a little smaller size. But, as we can see judging by the
snip from the CLI it is a little bit slower than just using a
constant bitrate while encoding. But, if you want higher quality, and
you aren't too concerned about the size, I'd say go for it. If you
still want to use VBR, but want smaller files you can always raise
the value of the "-V" switch.
{p} {p}
Well, that's about it from me - there are tons of other ways of
encoding, but what I have described here are the most commonly used
ones I guess, so that's a good start. Now, if you're curious on LAME,
and the MP3 format I suggest you point your browser instantly to the
links below.
{p} {p}
As a final remark in this review I'd like to comment a little about
the mis-conception about MP3's being illegal as many seem to think.
This is however not the case - MP3 encoding is merely a form of
compressing audio, the technology itself isn't illegal, it's what you
do with the results of the usage of an MP3 encoder that might be a
legal dispute. That's something to keep in mind. Isn't it?
{p} {p}
All tests were carried out on a 060 @ 66 MHz
{p} {p}
{bold}Available from{nobold}: http://www.honeypot.net/audio/archives/LAMEbeta.lzx({link http://www.honeypot.net/audio/archives/LAMEbeta.lzx}Download This{end}){p}
(this should always be the latest beta release by the way)
{p} {p}
{bold}Overall{nobold}: 89%
{p} {p}