Podcasting is a relatively new technology for distributing audio and video files. This article will focus on audio podcasting. While the idea of producing audio files and sending them over the Internet is not a new idea, having new episodes of an audio file automatically pushed to “subscribers” is. This is accomplished by having a program on your computer that reads a special XML feed file to automatically download new episodes of a show. XML files are similar to RSS files that are used by news readers to keep up with new posts on websites and blogs.
Audio Files Basics
While podcasting refers to a delivery system, the product being delivered is an audio file (videos can also be delivered by an XML feed, but this article will focus on audio podcasts). So let’s start by getting a good understanding of audio files.
There are many different formats of audio files. The most prevalent file format in use is the uncompressed format used to produce music on CD-ROMs. This file format, which produces a high quality output, is too large for distribution over the Internet. For example a 700 Megabyte CD-ROM can only hold about 70 minutes of music.
To make it practical to distribute audio files over the Internet and to install them onto portable audio players, the files must be compressed to reduce their size. The most popular file compression used today is the MP3 file format.
Most audio files are recorded in an uncompressed format (usually the .WAV format) and all the editing is done in this format. After all editing is completed, the uncompressed .WAV file is encoded to an MP3 file. This process will drastically reduce the size of the file. For example a typical 30 minute MP3 file will be approximately 20 Megabytes or less.
Note that there will be some loss in audio quality when you compress a file to less than 1/10th its original size; however, the loss is quality is barely noticed with a spoken word podcast.
Playing MP3 Files on Your Computer
The easiest way to play an MP3 file is to use your computer. Most computers come with media player software already installed. If your computer does not already have one installed, you can download one for free and install it.
The most popular media player is Microsoft’s Windows Media Player. It is typically pre-installed on all new Windows computers and is also available as a free download from Microsoft.
The most popular media player for an Apple computer is QuickTime. This program also comes pre-installed on Apple computers and is available as a free download from Apple. QuickTime is also available in a Windows compatible version which is also available for download from Apple.
The popular Apple iTunes program is available for both the Windows and Apple platform and can be used to play MP3 files. As covered later in this article, the iTunes program is much more than a media player. This program is available as a free download from apple.com.
Playing MP3 Files on a Portable Player
In addition to playing a MP3 file on your computer you can also transfer MP3 files to a portable MP3 player. This is where we need to clear up the biggest misconception of podcasting. You do not need an Apple iPod to listen to a standard podcast, any MP3 player can be used. You can find many portable MP3 players that will hold 10 hours of audio for less than $50.
There are two cases where you must use an Apple iPod. If you purchase and download music from Apple’s iTunes music store, you must play it either with the iTunes program on your computer or on an Apple iPod. The files are encrypted and will not play on a standard MP3 player. This; however, does not apply to standard podcasts. This is sometimes confusing since one of the most popular podcast directories is actually part of the iTunes music store. You must purchase music from the iTunes Music Store and the only portable device that can play it is an Apple iPod. Podcasts from the iTunes Music Store are free and are not encrypted and can be played on any MP3 player. Also note that the iTunes Podcast Directory is not the only podcast directory, just one of the more popular ones.
The second condition that would require the use of an Apple iPod is the portable playing of an “Enhanced Podcast”. An enhanced podcast uses a the .aac file format and must be played with the Apple iTunes software or an Apple iPod. The main advantage of an enhanced podcast is the ability to display multiple images during the file playback.
Playing an MP3 File in Your Car (or Any CD Player)
Be aware that a standard CD player will not play a MP3 file. An uncompressed file is compressed by a MP3 encoder and must be decompressed before it can be played. A CD player must be equipped with the MP3 CODEC to decompress the file so it can be played. Some radios come equipped with the MP3 CODEC, but most standard radios are not.
Some high end radios come with a “line in” plug on the face so you can use something like a portable MP3 player to provide a source of music. You would simply use a cable to hook the output of the MP3 player to the “line in” plug on the radio. Some automotive radios even come with a docking port for an iPod. In this case you could plug your iPod right into the radio face and play any music from the iPod.
The Podcasting Client Software
OK…. Getting back to podcasting. Since we know about all the pieces, let’s look at the piece of software that makes this all happen.
At the core of the podcasting system is a piece of software called a podcast aggregator. A full featured aggregator will have the following features:
- Integrated with a podcast directory
- Allow you to subscribe to a podcast
- Manage the downloading of future episodes of a subscription
- Allow you to store downloaded audio files on your computer in a manageable fashion
- Play MP3 files
- Synchronize music from the desktop computer to a portable MP3 player
While there are many podcast aggregators available, Apple iTunes is the most popular. It is available as a free download from the Apple web site for both the Apple platform and the Windows platform.
Note that you still have the option of downloading a MP3 file one at a time and playing them with a media player. Most websites, or blogs, that produce a podcast will allow you to download single episodes. A program like iTunes really “shines” when you use it to subscribe to podcasts and let it manage the downloads of new subscription episodes.
Podcasting Summary
The big picture is that now you can control what you listen to and when you listen to it. While you are exercising, mowing the lawn, or commuting to work you could choose to listen to automotive training content (or about any other topic you can dream up) instead of broadcast radio.
With the ability to easily purchase single songs and the large amount of podcasts that are available, it is easy to inexpensively put together a large inventory of content that you can listen to on your time. You no longer are restricted to broadcast radio.
Here is a video that explains podcasting, “in plain English”.