MP3 File Format

What is MP3 ?

MP3 is an audio compression technique that allows you to compress audio

by a ratio of between 1:4 and 1:12 and still keep the original quality

of the sound. The sound retains the CD like quality and will end

up as a file many times smaller than the original .WAV size.

Sound samples by MP3

If you have found my homepage you also like this kind of music. Because this music

is no longer created it is difficult for people to know of its existance.

People like me who don't hear it on the radio, have no idea of the existance of certain

bands and groups that created this music.

MP3 allows the transfer of audio files over the internet at minumum size, for the

purpose of EVALUATION ONLY so we can decide if to buy the CD or not..

I encourage the transfer of sound samples as this gives us the opportunity to test music

we normally don't have the chance to, and if we do decide it is good, go and order the

original CD.

MP3 evaluation also encourages the sale of music to a greater number of customers.

Who can play MP3 ?

All that is needed to play MP3 files is a pentium computer with soundcard

running Windows 95 and a program like WinPlay (or Winamp).

Alternatevly you can decode the original .WAV file with a decoder like

L3DEC and play it under DOS or Windows with your soundcard software.

Who can create MP3 ?

To create an audio file encoded MP3 you need an audio source in .WAV format.

This can be the sample from a soundcard (Low quality) or the source can

be songs ripped off CDs (The preferred method).

You need a CDROM that can read raw audio sectors, enough diskspace (raw

audio takes up about 10Mb per minute), you also need an encoder like

L3ENC. To rip music off CDs you need a program like CDDA or DAC.

Not all CDROM drives support reading of raw audio sectors off CDs.

Most of the drives sold today can do it, and all SCSI drives can read

audio. All CD-R drives can copy audio.

What drives support raw audio sector copying ?

Here is a partial list of drives I know support reading audio CDs.

This list is based on feedback from people I'm in touch with. If your

drive supports DA sector reading, and is not in the list, please

let me know.

Apple 300, 300i, 300e

Sony CDU-8003, CDU-8003A, CDU-8012

Apple CD300+

Chinon CDS-535

COMPAQ CR503/CDU561

DEC RRD42

Goldstar GCDR-540 IDE

HP 4020

NEC CDR 200, 300, 400, 500, 600, 900 series

NEC CDR 84-1/74-1 (rumoured with special firmware)

Panasonic CR-562B/563B/572/574/581

Pinnacle RCD1000/5030

Pioneer 124/624

Plextor 4Plex/6Plex

Sanyo C3G IDE

Sony CDU-561, CDU-31A, CDU-33A, CDU-55S, CDU-55E, 76E/76S

Toshiba XM3301 (Silicon Graphics)

Toshiba XM3401, XM4101, (XM3501 with 0925 and later firmware), 3601, 5302

Hitachi

Matshita (Panasonic) 503

Yamaha CDR100/102

Kodak PCD225,6x

Philips CDD522

Plasmon RF4100

JVC XRW2001

Ok, how do I do it ?

Encoding and decoding MP3 is easy if done right. You will get a very high

quality audio file that takes up a fraction of what the original did.

You have only to follow these simple instructions and you'll do it in

minutes.

1.

Get the CD source. You can use DAC or CDDA or any other software you

like. DAC must be run under DOS (not a DOS window). You will get menu

with a list of tracks on the CD. You select the track you want and press

F2 to copy it to a filename you specify.

CDDA in my opinion is better. It is a command line utility that can

run under DOS or Windows (in a DOS window).

I prefer running it under DOS.

You specify the line

cdda.exe /t 2 /f filename.wav /w /o

to rip track 2 to a wav file called filename.wav.

/t 2 - means that I want to record track number 2

/f filename.wav - means to write to File - filename.wav

/o - copy protection override - must me used for audio

/w - means that format must be WAVe

and there you have it ! The song is now a WAV file.

2.

You now need to encode the file to MP3 format. For this you need

a program like L3ENC. Using this utility the command line would be :

l3enc filename.wav filename.mp3 -br 128000 -hq

-br 128000 - means, the file will be converted at bitrate 128Kbit/s

filename.wav - input file filename.mp3 - output file

filename.mp3 - this is the name of the MP3 file you will get.

-hq this means high quality. You don't have to use this option

You will now have a file called filename.mp3 .

This file is still sampled at 44.1KHz stereo, 16 bit , just like

the origanal WAV, only 10 times smaller !

You can now delete the WAV file which is not needed anymore.

That's it, easy isn't it ?

The MP3 file which you now have can be played back with Winplay by you

or anyone else who has a soundcard. If you want to decode the original

WAV back from the MP3 you would type

L3DEC filename.mp3 filename.wav -wav

Now you'll get a file called filename.wav .

If you want a sample

If you'd like a sample of this kind of music, go to the main page

and view my music list. Tell me the names of the songs you'd like,

I'll send it to you by ftp to a server you find (I have no FTP space).

If you like it please go buy it in your record store, or over the

internet stores. I want to encourage you to buy this stuff, not

copy it. If you decide not to buy the CD, delete the sample.

I am also looking for this kind of music, if you have something I

don't have, send me a sample, I'm always looking for new CD's

to buy.

What Software should I get ?

I have mentioned many different programs here, which is best ?

Ripping CD's audio tracks is the first step.

This can be done with many programs.

I have a CDROM that allows the extraction of raw data and have tested

two programs, DAC and CDDA.

DAC is a program that must run under DOS (not a DOS window).

You will get a window with the list of tracks found on the disc.

Move the cursor to the track you want and copy it with F2 to a filename

you specify.

CDDA can be run under DOS or windows. This is a command line wtility

which gives you total control over how you rip the track.

I would suggest using the default values as the program knows what it

is doing and in most cases this gives optimum performance.

You copy the audio track by following the steps I wrote in a section

above. The copying of audio with this program can be highly optimized

by creating a batch file that does all the work for you.

Here is a sample batch file that I use for copying audio tracks

the batch files is called CP.BAT

cdda /t %1 /f %1 /w /o

cdda /t %2 /f %2 /w /o

cdda /t %3 /f %3 /w /o

cdda /t %4 /f %4 /w /o

cdda /t %5 /f %5 /w /o

If I want to copy tracks 1 3 5 6 9 I would type the following line

CP.BAT 1 3 5 6 9

after which the program copies the selected tracks to the filenames

1.WAV 3.WAV 5.WAV 6.WAV 9.WAV

It's as simple as that !

Next you should find an encoder.

There are a few freeware encoders that do the job well. The program

I found most suitable is called L3ENC. This program is shareware.

The trial version allows you to sample at miximum 112KBs, which is not

the optimum for music, this is however enough to allow you to try the

program before you buy it.

To get true CD quality you have to encode your WAV file at a bitrate

of at least 128000. For this you need a registered version of

the L3ENC encoder software. With the registered version you can create

MP3 files encoded at bitrates of up to 256000 . This gives you a file

of true CD quality, at full stereo, 44.1KHz, 16 bit.

L3DEC is the decoder that gets the original WAV out of the MP3 file.

You also need a player for MP3 files. The minimum hardware recommended

is a 486DX50 computer. A pentium is needed for stereo samples.

If you have an older computer that cannot keep up with the CPU intensive

real time players you could always decode the MP3 and play the WAV

file later - even on a 386 machine. Use your souncard software to play

the WAV file, or any other software found easily on the web (shareware

and freeware utilities are widely available).

A little technical stuff... more than you probably wanted to know.

What is to follow might be very boring for some readers and can quite

happily be skipped. I'll try to give as accurate description of the audio

compression technology as possible including the various sampling

techniques. At the moment I don't have much time to give much detail but

I hope to fill it in as soon as possible.

The method is called PSYCHO-ACOUSTIC COMPRESSION which means the file being

played does not contain the whole sound sample actually recorded (As in a

WAV file), but only the parts of the music the human ear, and brain can

distinguish from the music. This is somewhat like a picture in which you

reduce the resolution up to a point where the eye can barely make out the

difference. This of course saves valuable disk space.

The source file is split into a few key frequencies and a volume sample is

taken, this resembles the spectrum analyzer you have in graphic equalizers,

only this is the other way around. This way you make up the "resolution" of the

sample , ie. the number of bits in the .MP3 file. For example in a 128KBs

sample you have 128000 bits of information per second, not recorded as sampled

digital music , but as music volumes at different frequencies. The more bits

you have per second , the more accurate the reproduction of sound you get.

This is not exactly correct as there are different ways of creating the optimum

file. For low resolution samples, those 56KBs and below speech samples, the

entire acoustic spectrum is not sampled, only the frequencies referring to

speech are taken into account, thus saving valuable unused samples not included

in the human voice. In this way we reduce the size of file without affecting

the quality of speech. This method is good only for speech as the entire audiable

spectrum is not reproduced.

The medium sized samples (96KBs and 112KBs) use a different algorithm than used

for speech. Here we want to get a wider range of frequencies and still keep the

file small. The highest quality samples (128KBs, 192KBs, 256KBs) work a little

different.

More to come if time permits.

Final words ...

I hope this has helped you, I'm sure you'll enjoy this new audio standard

which is both high quality and not space consuming.

Let me give you one final word of warning,

Copying of audio is both unethical and illegal.

Hearing music samples for evaluation is ok, if you like what

you heard, go buy it !

I want this music to spread, allowing more people to know of it's

existance, MP3 is the perfect way. Sending samples across the globe

breaks the barriers of distance, please don't take advantage of

this technology to create piracy.

Today there are quite a few music stores on the web allowing you to

directly download songs as MP3. This saves you the expenses of shipping,

also giving you immediate access to a wide range of songs of your choice.

Almost for free, for the first time ever, you can buy music, from your

own home, only at the time it takes you to download the files.

With such excellent service, you can forget about the costly music stores

and get exactly what you want, exactly now. This saves you lots of

money, as you save on shipping and the price it costs to own a store.

This should give you enough reason to go and buy a song you like

instead of stealing it.