Streaming Audio Primer (Part 1):
How to Put Streaming Audio on the Internet

"What is this all about?" Well, this page describes a procedure that enables you, a web page designer, to either record or copy audio files from cassettes or CDs and place them on your web page, available for downloading and streaming. This procedure will provide a web-surfer the opportunity to download high quality audio files and listen to them with a free player. A second option can also be provided that would allow someone to listen to the audio file immediately, similar to streaming audio, such as Real Audio. However, the process that is described here is different than audio streaming technologies, such as Real Audio, in that once a surfer has downloaded the file, he or she can listen to it as much as they want without having to be connected to the web. Another key difference is that it is almost free for the web page designer. The costs will vary depending on what software you choose to accomplish the translation procedure. The key to all of this is the magic of MP3 (or VQF) encoding.

Overview

There are 5 basic steps to creating audio files and putting them on your Web site:

1. Setting up recording hardware.
2. Record the material as a WAV file.
3. Remove Noise and Static (optional) from WAV file.
4. Compress and Encode the created WAV file into the MP3 format.
5. Update your web page with the new files and appropriate links.
   

But first, a glossary of terms for the beginners:

What is . . .

• Bit-rate: (bps = bits-per-second) the rate at which bits (1 or 0 - a single piece of information) are streamed through a system. A prefix of k (ex, kbps) means that the units are multiplied by 1000, i.e., 28.8 kbps = 28,800 bits-per-second.
  
  
• Freeware:  software that is free to use forever. There are no strings, no catches. However, some programmers ask that you not tamper with the software and redistribute it, while other go so far as to provide the source code for the program.
  
  
• Shareware:  software that is free to download or share with friends. Typically it comes crippled or with some kind of nag built in to encourage registering the software. It is understood that to honestly use shareware, you must register the software after you have tried it out and if you decide to keep it. Otherwise, you should erase it. Registering costs vary from product to product.
  
  
• Shareware Demo:  software that is provided with the same understood policy as shareware; however, it is typically severely crippled and may not even be able to save files. Often the full registered version is of higher quality than plain shareware, but it is usually more expensive too.
  
  
• WAV:  a sound file format that is uncompressed. WAV formats perfectly preserve the audio information with zero compression. Therefore, they are very easy to decode and translate into sound, but they also produce huge data files (250 Mbytes for 40 minutes of mono sound).
  
  
• MP3:  a sound file format that follows a standard compression technique, officially known as MPEG 2 Layer-3.   Video and audio can both be stored in the MP3 format. Virtually no audio information is lost in converting to the MP3 format if the same sampling frequency or greater is used for encoding compared to that used in the original recording. MP3 files are much smaller than the original file (5.5 Mbytes for 40 minutes of 16,000 Hz Mono). Requires a special program for playback which can be downloaded for free from many sites. Check out the Web site of the guys who invented the MP3 format and are busy on MP4.
• VQF: another sound file format that works based upon a similar principle to the frequency-based encoding of MP3. Achieves higher compression through vector notation. Slightly lower quality than MP3, but smaller files too. Not yet as popular as MP3. For more info, check out my comparison as well as the site of those who invented VQF and the site of those who are pushing it:

Pushers - Yamaha's Sound VQ
Inventors - NTT Human Interface Laboratories

• Streaming Audio a method of playing audio files from the web. The audio is played as it arrives off the Internet. The file is not preserved on the computer, so a network connection must be sustained to play the audio file. A variation of this method is employed here, called pseudo-streaming. Real Audio uses a variation that dynamically compensates for slow connections.

Comparison to Streaming Audio

"Sounds great, but how does this compare to the Real Audio Player and other streaming Audio?"  That's a good question. The MP3 and VQF formats and the above described system is logistically different than streaming audio, but a web page can be configured so that there is almost no difference to the listener.

With dynamically streaming audio, a listener's computer decodes the file as it arrives via their modem, and if their modem is too slow, then the server will automatically compensate by reducing the quality (bandwidth) of the audio. So, they can begin listening immediately and terminate at any time. This allows for immediate and easy listening regardless of your modem speed. That's the advantages of dynamic streaming audio. Here's the disadvantages:  A streaming audio delivery system is not quite free, or even almost free. It's can be more like $10,000 shy of free!  You would need your own computer (dedicated server) with special equipment and a high bandwidth connection, devoted to constantly exporting files. The computer would be mega-expensive; the setup labor could be expensive; and the Internet connection would definitely be expensive. It's the oldest and most well known technique, but it's too expensive for most churches or an individual to attempt. Of course, one could also pay to have all of this done, rather than doing this themselves. Also, Real Audio files are often 2-5 times bigger than a comparable MP3 or VQF!

But what about MP3 and VQF?  Obviously, MP3 and VQF have the clear advantage in file size. So, they can have much better quality in a smaller size. But, there is no way to stream MP3 or VQF - or is there?  MP3 and VQF can be dynamically streamed like Real Audio if a server is setup for that, but whenever people post a MP3 or VQF, it is usually not on a server devoted to streaming MP3 and VQF. However, it is possible to begin listening to MP3 and VQF files immediately using pseudo-streaming techniques. The advantage of this technique is that it requires no special server software or configuring. Anybody can take advantage of this without having to contact their web-site host or know anything about servers.

Any MP3 or VQF player can be used to listen the streaming audio. This makes it just as good as Real Audio, except that it does not support dynamic bandwidth compensation. Since the server does not try to compensate for smaller connection bandwidths, small pauses may occur while a listener's computer waits on downloading more of the file. However, this usually only a problem for really slow modems, much slower than 28.8 kbps. Test out your modem on my page where you can try out NetPlayer on the MP3 files that I have posted. Without having the overhead of the dynamic bandwidth compensation, MP3 files can be streamed at higher quality for the same bandwidth. So, for almost all cases, the MP3 files sound much better than Real Audio.

Also, this whole setup allows you to check it out for free. All of the software is free for trying out, and the few one-time registration fees are feasible. Also, once a user has downloaded your files, then he or she retains them. It physically exists on their hard drive, unlike streaming audio, where the audio file is preserved on the server's hard drive (the web). So using the either the MP3 or VQF system, a user can repeatedly listen to a sound byte, once its downloaded, without having to connect to the Internet. They can pass it to friends on ZIP disk. For more information, please see Web Page Updating and Pseudo-Streaming Players.

Now that you have had a good introduction to the whole process, let's proceed to the first step:  Making the initial Digital Recording.

Part 1: Introduction
Part 2: Digital Recording
Part 3: Reducing Noise
Part 4: Encoding
Part 5: Web Pages

Reprinted with permission from author Trevor Bowen, whose Web site contains good information on utilizing the digital medium.