The MP3 File Format: Demos and Information

To all visitors, especially webmasters with links to this page: Auto-forwarding from this page's old web address is only temporary! Please note the correct domain name (online-communicator.com), and update your bookmarks. Thanks!

t was May 1999, and I was attending a meeting where people were going to demonstrate MPEG-1, Layer-3 (MP3) audio. The next thing I knew, I had "volunteered" to write an article about the meeting for the Philadelphia ITVA newsletter. After doing the research, I decided to set this page up to share some of what I had learned. Some ITVA members may have seen that article by the time they read this web page. For you others, the expanded and enhanced version of that article is available right here on this website.

The meeting inspired me to explore MP3 for my own use, and among other things, this page shows some of the results. As test material, I used samples of my own narration work, since I am naturally very familiar with the original sound quality. Not only will you see the size savings using MP3 compression; you can also do your own listening test, comparing a couple of the MP3 files to the same sound samples stored in older file formats.

First, the new files, in MP3 format. The chart shows the incredible size savings achieved. (NOTE: when you click on any Download link below, in some browsers the download may begin immediately. In others, you may get a warning message about a "possible security hazard." If so, don't worry. That message is normal when downloading an unusual binary file type like MP3. Believe me, these are just sound files, and pose no threat. Enjoy!)

The Process

First, I sampled each sound clip into standard Windows WAV files at 44,000 Hz, 16-bits, which is essentially "CD-quality," to get the most out of the source material. Since the sources varied greatly, that high a sampling frequency was overkill in some cases, but I wanted the process to be consistent. The files were all monaural to start with.

In the second step, when encoding them to MPEG, I chose one of the lowest settings for "bit rate" because that reduces the file size, and does not seem to make a radical difference in the sound quality when played back over a typical computer system. (I look forward to getting input and opinions from visitors here as to whether that compromise on bit rate is indeed acceptable.) Further on, you'll find a few of the identical samples in other file formats, so you can compare the resulting quality if you're interested.

For now, I am still exploring MP3's possibilities. But so far, I can't argue with the performance of MP3 as a highly efficient audio compression algorithm and file format. MP3 is a "lossy" algorithm, in that it throws away data in order to shrink the file. However, it is designed "psychoacoustically" so that you and I are not supposed to notice the missing data. That's why the files still sound surprisingly good after shrinking so much.

Tools

Many programs will digitize an analog input signal, using a standard computer sound card. There's one included in Windows 98, and many sound cards include a small utility for that purpose. I used an old copy of "SoundForge" that I had available. Besides allowing for easy editing, it has other features for preparing the WAV files. (Note: when preparing the older files below using Windows 3.11, I used a shareware program called "CoolEdit." The Win 3.11 version of that program is available elsewhere on this website for download.)

Compared to the plethora of simple recording programs, there are comparatively fewer that encode MP3. But still, there are several to choose from, and more appearing every day. I used a trial version of the "Sound Limit" encoder from Eastern Digital Software [Revised URL] to turn the original WAV files into MP3. I want to try other software before fully committing to this program, but it seems to have gotten the job done for now.

How to Play MP3 Sound Files:

MP3 playback can be done with several programs, and that list is also expanding rapidly. I used one of the better-known programs in this category, called "WinAmp," for testing my results. It is a multipurpose program for Windows users, and useful for playing back WAV files, inserting author data into files, and more.

WinAmp was "shareware" ($10) when I first put this page online. Now, just a few months later, it is free -- and is even included with the latest versions of the Netscape Navigator web browser package. You can find MP3 files, and playback systems, everywhere you look nowadays.

A company called XAudio provides the decoding software "engine" for numerous MP3 players, for multiple types of computer environments, including Unix, Windows CE, AIX, and of course, Windows and Macintosh. You can go to the XAudio website [Revised URL] for more information and/or free downloads.

Compare

For comparison, you will find links below to files that are already accessible elsewhere on this site. When I created them three years ago, I was concerned about file size because of the Internet bandwidth/speed issue, so I edited them as tightly as possible, then digitized them with a very low sampling rate of 11KHz, 8 bits per sample, monaural.

Despite that low rate, they don't sound that bad, since they are mostly concerned with voice (as opposed to music). But as you can see from the numbers above, the MP3 versions of these same samples, originally sampled at a higher rate, still result in smaller file sizes. If you're interested, you can compare the quality between these two formats by listening to the files below and their counterparts above.

NOTE: Please don't download all 3 versions of each! If you have a compatible player, they will all sound identical. The different file formats are simply provided as a convenience for users with varying types of computer systems.

Journey Toward the Light (excerpt; short version) (155K)

| WAV format | | AU Format (Unix) | | AIF format (Apple) |

Voices of a Small Town 100 Years Ago (216K)

| WAV format | | AU Format (Unix) | | AIF Format (Apple) |