MPecker Encoder
MPecker Decoder
MPEG Links

MPEG 1 Layer III audio (common called MP3, but it is still Mpeg 1!) is becoming popular in audio business at high speed. The difference between an original 44 Khz CD-quality audio file and a Layer II audiofile can hardly be heard, when encoding is done right. Where 44 Khz files take up to 10 MB per minute stereo audio, MPEG compressed files take as little as 10% to 15 % of the size of the original. Thus: 10 minutes of stereo music at 44 Khz take about 100 MB in almost-CD quality, but only about 10 to 15 MB in MPEG Layer III format. And is still sounds great! Only the true trained ear can hear the difference. That's why MPEG audio never will be used for mastering a CD, but is perfect for presenting your audio. On the WWW for example, or on a homestudio made demo CD, playable in a Mac and/or PC with the right MPEG player software.

When you want to produce your own MPEG-files, you will need an encoder. If you just want to listen to MPEG files you will need a decoder.

MPecker Encoder.

The best one we found is the MPecker Encoder, made by Rafael M. Leubbert. In fact, at the moment this encoder is the only one available for the Mac that supports Mpeg 1 Layer III encoding. You can download the most recent version at the following site:

This encoder is rather slow (as all conversion to MPEG format is time consuming by the way), but does it's job very well. The sound stays clear and crisp, just like the original, with only a slight loss in the high area.

Here is some more info on this encoder, written by Leubbert.

(c)1997 Rafael W. Luebbert - All Rights Reserved.

Mpecker will run on any MacOS PPC machine, and will encode AIFF files sampled at appropriate frequencies into mpeg files. It will also encode 44100 Hz PCM files as well. Supported sampling frequencies are:

44100, 48000, 32000, 24000, 22050, and 16000 Hz.

To start the program, double click on the MPecker Icon, or drag your aiff file(s) onto the icon. The program will start. If you have used MPecker Encoder before, your previously used preferences will automatically be loaded and set.

To add more files for encoding, either drag their icons onto the application's icon, or use option-M or Modify Batch List from the Menu, and add files there. The program will hold 256 different file names for encoding. To open and encode just one file, you can use option-O, or Open File. After you select the file, it will start encoding. To start encoding the batch list, choose option-E, or Encode Batch List from the File menu. All files in the list will be encoded, no matter what type of file they are. Warning: This means text files, binary files, ANYTHING you add to the list will be encoded.

Converting CDDA to AIFF files.

Select this option from the files menu. IMPORTANT: Be sure to select the options button at least the first time you use this feature, or you will get some random conversion. Your converted files MUST BE 16 BIT! Mono or stereo is up to you. Your sampling frequency must be one of the supported sampling frequencies mentioned above. Next select a place and a name for the file and the computer will do the rest.

The Priority Menu.

You can change the amount of processor time the encoder uses by selecting one of the three options in this menu. The default is "Run like a good mac proggie" and this will "yield" to most every other process running. It will also considerably lengthen your encoding time. The two other options increase the number of encoded frames between CPU "yields", and also increases the amount of time between encoder window updates. It will also make other programs a bit "jerky" as interrupts are serviced less frequently.

The Options Menu.

Here, you can choose several different options for encoding your file. If you know nothing about MPEG, use joint stereo, 128 kbps, layer III.

Layer II or III.

These are different means for encoding music files. Layer II is less complex, but sounds better at higher bitrates. Stereo reproduction in this layer is very good for bitrates of 128 kbps and up. Layer III is the most complex of the implementations. It combines the features of layer II, plus a modified FFT and a Modified Discrete Cosine Transform (MDCT) to the encoding process, and also "packs" each frame using Huffman encoding, thus it takes ALOT of computation time to encode in layer III.

There is a great deal of debate on whether layer II or layer III is the more robust of the encoding implementations. At bitrates of 128 kbps and higher, arguably layer II is better at reproduction in my opinion. Nevertheless, there is a bias toward layer III on the internet, probably only because it is more complex, and because III comes after II, rather than any real audio difference between the two. Certainly, however, at bitrates lower than 128 kbps, layer III has the upper hand.


The bitrate is the number of bits used to encode the audio sample for each second of music. For example, a bitrate of 128 kbps means that there are 128,000 bits (16,000 bytes) used to encode each second of music. While that sounds like alot, realize that there are 176,200 BYTES (1,409,600 bits!) for every second of music in a 44.1 kHz stereo AIFF file. Thus you can see the significant advantage of encoding in MPEG audio.

In general, most people will leave the bitrate at 128 kbps, as most people are encoding stereo files. Mono files can be encoded at lower bitrates - 64 kbps will probably work nicely. For both stereo and mono files, if you find your particular file sounds "distorted" or like music is "missing," try a higher bitrate.


There are three modes of encoding: Mono, stereo, and joint stereo. Mono is just an encoding of a one channel file. Stereo makes an encoding of a two channel stereo file. Do not worry too much about mono vs stereo if you are using AIFF files, as the program detects mono files and will adjust the encoding accordingly.

The term that may sound unfamiliar is "joint stereo." Joint stereo is an encoding algorithm used to increase the quality of the encoding. If the total distortion of the music exceeds an implementation dependent value, then subbands of the audio are combined, highest frequencies first, so that less space is required to encode the entire file. This tends to make the treble sound a bit flatter than a stereo encoding would, but improves the reproduction of the mid and lower range frequencies.

The most common encoding settings found in MPEG files on the internet are: 128 kbps, joint stereo, layer III. See my layer discussion above. For your own purposes, you may want to experiment with different settings to generate your favorite "flavor" of MPEG files. My personal preferences are either layer II stereo 128 kbps, or layer III stereo 128kbps.

Do not confuse MPEG layer III with MPEG-3. There is no MPEG-3 as an IS. MPEG-1 is the original MPEG audio standard, and has layer I, II and III encoding. It supports 32 kHz, 44.1 kHz, and 48 kHz sampling rates. Thus, all files encoded from a 44.1 kHz sampled file are MPEG-1 Layer I, II or III files. MPEG-2 was developed after MPEG-1 with the goal of supporting lower sampling frequencies. MPEG-2 supports 16 kHz, 22.05 kHz, and 24 kHz sampling frequencies, thus all files encoded from a 22.05 kHz sampled file are MPEG-2 layer I, II or III files. The commonly used suffix ".mp3" is commonly referred to as "MPEG 3" files, but really, it is an MPEG-1 or MPEG-2 layer III file, depending on the sampling frequency as discussed above.

More info.

More detailled info (version history, registration info, credits, non-commercial use of the encoder) can be found at Rafaels site:


Updates for both the MPecker Encoder and the MPecker Player/File Converter can be found at the MPecker website at

Mail the Maker.

Rafael W. Luebbert can be reached at: or

MPecker Drop Decoder.

When you have built a collection of MP3-files you may want to listen to them. The MPecker encoder by Luebbert mentioned above) has a decoding brother, the MPecker Drop Decoder 1.2. It can be downloaded at


A nice player is VAMP, developed by Michel Pollet. You can download the VAMP-player at


The newest version of good old SoundApp (status: version 2.4.1) can play MPEG-files as well. Earlier versions choked on the Layer III files: this version works fine! On our AudioFormats Page you will find information about all audioformats with the ones SoundApp supports highlighted.

SoundApp 2.4.1 can play or convert files dropped onto it in a variety of formats. In addition, it supports Play Lists which are lists of sound files that can be saved for later usage. Files in a Play List can be played or converted as a group or individually. SoundApp supports a randomized shuffle playback mode and repeated playback of Play Lists.
The following sound file formats are supported:

  • SoundCap (including Huffman-compressed),

  • Studio Session Instruments,

  • SoundEdit (including stereo, MACE-3 and MACE-6),

  • AIFF, AIFF-C (8-, 16-, 24- and 32-bit, MACE-3, MACE-6, IMA 4:1 and µ-law),

  • System 7 sound and 'snd ' resource (including MACE-3, MACE-6, IMA 4:1 and µ-law),

  • QuickTime MooV (soundtracks only, including MIDI movies),

  • Sun Audio .au and NeXT .snd (including µ-law, a-law, 8-, 16-, 24- and 32-bit linear, 32- and 64-bit floating point, G.721 ADPCM and G.723 ADPCM),

  • Windows WAVE (including GSM-, IMA- and MS ADPCM-compressed, µ-law and a-law, 8-, 16- and 32-bit linear),

  • MPEG audio (layers I, II and III, requires a PowerPC processor),

  • Sound Blaster VOC,

  • many varieties of MODs,

  • ScreamTracker 3 module (S3M),

  • Multitracker module (MTM),

  • MIDI (type 0, 1 and 2, including GS and XG),

  • Amiga IFF/8SVX (including stereo and compressed),

  • Sound Designer

  • Sound Designer II,

  • IRCAM (8-, 16-bit and 32-bit floating point),

  • PSION sound,

  • DVI ADPCM and

  • raw GSM.

SoundApp can convert all of these formats to System 7 and 8 sound and sound suitcase (linear, µ-law, MACE-3, MACE-6 and IMA encodings), AIFF (linear, µ-law, MACE-3, MACE-6 and IMA encodings), WAVE (linear, µ-law, a-law and IMA encodings), Sun Audio and NeXT (linear, µ-law and a-law encodings), Sound Designer II, QuickTime (linear, µ-law, MACE-3, MACE-6 and IMA encodings) and PSION formats. SoundApp also supports generic QuickTime conversion, which allows any QuickTime-recognized format to be converted to a QuickTime movie file. This feature is provided as a convenience, as it is entirely handled via QuickTime. SoundApp is distributed as a "fat" binary for native PowerPC and 680x0 usage.

You can download the latest version from:


MacAmp's roots are in the UNIX world. Later, the MPEG-player was ported to Windows, and now it has made it's appearance on the Mac platform as well. There is only a PPC-version available. Though still in alpha version (v1.09a in november '97), it is quit stable. You can download this new player from Euronet's TUCOWS softwaresite:


Of course there are a lot of FAQ's on MPEG Audio Layer III on the Net. We scanned a lot of them on their content and made a link to -what we find- the best of them all: the english FAQ at Frauenhof, Germany. This institute is known as the "place of birth" of MPEG audio. They have an excellent FAQ-page on their site. The information their is copyrighted, so we cannot place the information within our site. In stead of that, we provide you two links to Fraunhofer where you can get the latest information and answers: At the URL you will find a HTML-version. You can download the same file from

MPEG Links.

Here are some links where you can find and download interesting MPEG Audio files. Caution: some (well, most...) sites offer illegal copies of audio CD's or tracks. By downloading and using these files, you take the risk of lawsuite! AudioMac provides these links here, but cannot be hold reponsible for lawsuit consequences when you run into trouble! We provide some "Windows"-links too, as also on this platform MPEG is common used.

Caribe Son
CD Worx: "rip" audio CD's to MPEG3-files.
CDDA and CDDA32: straight forward CD-"rippers", running under plain DOS (CDDA) of in a Windows'95 DOSbox (CDDA32).
CD2WAV: CD-"ripper", Windows only.
Internet Underground Music Archive audio streams of unsigned artists.
Links to MPEG-sites:
Links to MPEG-sites:
Links to MPEG-sites:
Links to MPEG-sites: (part of the Music WebRing).
Maz's Home has a lot of utilities for encoding and decoding music in general.
MPEG Audio Zone - The Music Shoppe has some classical music in MPEG Layer II format, and also MIDI format.
MPEG Archive
MPEG-Archive MacOS
MPEG Audio Layer 3
MPEG Audio Software
MPEG Mac Software
MPEG.ORG - MPEG Pointers and Resources
MPEG.ORG - MPEG Audio Resources and Softwares
MPEG-2 Archive
Natural Elements Records
Oliver's MPEG Software
PHADE's Top 100 MPEG links
Playloud! Music in France has songs from various French music groups. I hope you understand français!
Search Engine for MPEG-3 files.
Smashing Pumpkins Audio Archive has a collection of 300 full length Smashing Pumpkins songs in mp3 format.
SongSite (1).
SongSite (2).
The Ultimate Nirvana .MP3 Page
WinAmp: MPEG player, also available for Macintosh!
WinPlay3: Windows only.

All reviews in are written by Peter J. Bloemendaal. All rights reserved.

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