Podcasting is a method of publishing audio programs via the Internet, allowing users to subscribe to a collection of files, called a feed or channel. Any changes or files added to the channel are automatically downloaded to the user's personal computer, to podcast aggregator software like iTunes. These files can then be listened to later, at the user's convenience.

The goal of podcasts is to allow users to keep up to date with a range of different audio sources, world wide. The aggregator (grouping) software maintains a list of content sources and periodically and automatically checks the sources for new sound file releases.

Another benefit of podcasting is that listeners can sync the content of iTunes, or their aggregator, to their iPod or other portable media player, and take the audio files with them to listen to, whenever they want.

The following instructions for creating a podcast are for both PC and Mac. QuickTime 7 Pro and Plantronics headsets with microphones are available in the Advanced Technology Lab, and the Digital Curriculum Center. The headsets for the ATL can be checked out at the Circulation Desk.

A. Directly into a computer with QuickTime Player 7 Pro.

1) Connect the USB Plantronics microphone headset to the computer.
2) Open QuickTime Player, go to Preferences>Recording
3) In the Recordings tab, make sure the Plantronics headset is selected as the Microphone. You can use whatever playback device you’d like. While recording, reduce the playback volume to 0 to eliminate interference.
4) While in Preferences>Recording, select Format: Uncompressed Audio (.mov). On the Mac, this setting is called Quality: Device Native. Select Save files to Desktop.
5) In QuickTime Player, go to File>New Audio Recording. Place the mic about 1” away from your mouth, off to one side and not directly in front of your mouth. When you speak, the level meter should register about half-way to two-thirds of the way.
6) Click the red recording button to start recording. Click it again to stop.
7) The file will automatically be named. To rename it, close the file, and rename it on the desktop. Do not rename open files.
8) If you disconnect the Plantronics mic while QT Player is open, the player may crash. Quit the player before you disconnect the mic.
9) NOTE: The above procedure provides quality adequate for many purposes, if you need better quality, you will have to use a better mic, or a different recording device, and a quiet location. Please see us for advice.

B. Classroom or field recording

1) You may use the above procedures, and record directly to a laptop.
2) We have wireless lavalier mics available, these allow you to move around while speaking and recording.
3) We have other portable recording devices: iPod with microphone, analog cassette recorder, Digital Audio Tape recorder, and MiniDisc.

We assume the audio was recorded as uncompressed. It is possible to record audio immediately in a compressed format. The disadvantages are that it makes it harder to edit the audio file later, if editing is needed, and to control the amount of final compression. We have special software to record compressed audio directly if you need to do so. Audio that is already compressed should not be recompressed again, there is a potentially large loss of quality.

When compressing, you need to decide whether to compress to mp3 or mp4 (AAC). mp3 is available on more devices, mp4 will generally sound better at the same file size and data rate, and is easier to compress. mp3 will play on all portable players, mp4 plays only on iPods, which can also play mp3 files. mp4 files can be used in enhanced podcasts, described later, mp3 files cannot. Either format will play fine on a computer, both formats are supported at Connecticut College.

A. To compress to mp4 (Also called AAC)

1) Open the file in QuickTime Player Pro.
2) Go to File>Export, Export: Movie to MPEG-4
3) Click on Options. Select File Format: MP4 (ISMA), In Streaming, do not select “Enable streaming”
4) In the Audio section, for voice recording select: Audio Format: AAC-LC, Data Rate: 32 kbps, Channels: Mono, Output Sample Rate: 32 KHz, Encoding Quality: Best. Click OK.
5) For music recordings (normal quality) select: Data Rate: 64 kbps, Stereo. For high quality select Data Rate: 128 kbps, Stereo, Output Sample Rate 44.1 KHz.
6) Name the file, with an .mp4 extension (the m4a extension is also used). Save it.

B. To compress to mp3

1) Open iTunes, select Library on the left.
2) Go to iTunes Preferences
3) Click on Advanced>Importing
4) Select Import Using: MP3 Encoder, Setting: Custom, Stereo Bit Rate 64 kpbs, Sample Rate: 32 kHz, Channels: Mono, check off any boxes below. Click OK.
5) Drag your uncompressed audio file into the iTunes song list, or go to File>Add to Library, and add the file. If you sort by Date Added, it will be at the top.
6) Select your file, and go to Advanced>Convert Selection to MP3. The new mp3 file will now be at the top. Select the file, and go to File>Show Song file. You can now copy and paste the file to your desktop. It will have the mp3 extension.
7) Reset you iTunes default Importing settings.

A. The audio file is uploaded to a web server, and has a specific and unique URL. We can upload the file for you to our servers.
B. You can listen to the audio file directly in QuickTime Player. For example go to File>Open URL: http://video.conncoll.edu/podcast/audio1.mp3 .You can save the file as a favorite by going to Window>Favorites, Add Movie as Favorite.
C. The file can also be played by a web browser, by going to the above URL. This may produce unpredictable results, it is better to embed the file in an HTML page.
D. You can listen to and save the audio recording in iTunes, by going to the Library, then Advanced>Open Stream, and entering the above URL. However, this audio file is not yet a podcast, although it can be copied to your iPod.
E. The advantage of a podcast is that any future audio files that are added can be combined in a "channel" or feed, and be automatically downloaded to iTunes. They can be played in iTunes later, or synced (copied( to an iPod. If your content hardly ever changes, a podcast may not be the best way to distribute it.

A simple podcast consists of an RSS file, also called a newsfeed, that references the above mp3 or mp4 audio file. Both the RSS file and the audio file are uploaded to a web server. More than one audio file can be contained in one RSS file. If you ever change or add content to the RSS file, any subscribers will automatically receive the changes.

The RSS file format, now at version 2.0, stands for Really Simple Syndication. It is an example of XML (Extensible Markup Language), a general-purpose markup language (HTML is a specific markup language) designed for creating special purpose markup languages, such as RSS. The technology behind RSS allows you to subscribe to RSS feeds, these are typically sites that change or update content regularly.

Until recently, RSS was only used for text-based news feeds. However, RSS 2.0 supports enclosures, or URL references to web content. Podcasts are simply the application of RSS enclosures to audio files. This makes it possible to use RSS files to link to audio files in a standard XML-based format.

We will create a very simple RSS file that contains one audio file. Use a text editor like Notepad on the PC or TextEdit on the Mac, a text editor does not include any text formatting, which renders the file useless. If you are using TextEdit, set Format>Make plain text, Wrap to Window. Use UTF-8 encoding.

Copy and paste this code into your text processor:

<?xml version="1.0"?>
<rss version="2.0">

<channel>
<title>Simple Podcast</title>
<link>http://video.conncoll.edu/podcast/index.html</link>
<description>Weekly Tech Tips</description>

<item>
<title>Color Management Basics</title>
<description>A reading from Real World Color Management</description>
<enclosure url="http://video.conncoll.edu/podcast/audio1.mp3" length="437514" type="audio/mpeg"/>
</item>

</channel>

</rss>

The above is all the code you need for a simple podcast. Extra spaces and carriage returns, outside tags, are ignored by RSS. Give your RSS file a name with an .xml extension and save it to your desktop. For example: podcast1.xml

The structure of the RSS File

1. The first two lines, and last line, in the rss file are always the same.
2. The RSS file descibes one channel, within the <channel></channel> tags. Only one channel is allowed in an RSS file.
3. Nested inside the channel are the items. Many items can be included, each item can reference only one audio file.

The nested tags describe the elements for the channel and its items, these tags describe exactly what your podcast is:

For the channel:
The main title of the podcast: <title></title>
The main link: this can link to any web page, but usually connects to a relevant web site.

For each item:
The title of it: <title></title>
The description: <description></description>
The audio file itself: <enclosure />
The exact location: url=" http://video.conncoll.edu/podcast/audio1.mp3"
The exact length of file in bytes: length="4834743". This length, actually the file size, can be determined by selecting the file, getting its size in bytes (File>Get Info on the Mac, Properties on the PC), and eliminate commas.
The type of file it is: type="audio/mpeg"

The best way to see how these elements are used in a podcast is to actually subscribe to the above podcast in iTunes (see part 5 below), and explore it.

There are other elements you can put into an RSS file. The example above is a very simple one. Below, in part 6, we will create a more complex podcast. The XML above describes a podcast beginning with <item> and ending with </item>. To add a second item, you can copy and paste the code between <item> and </item> and change the specifics. The most recent items are listed first in the RSS file, the oldest last.

Some rules about the tags:
1. There is always a beginning and end tag. For example: <Title></Title>. The exception is the case of what is called an empty tag. An example of one is the <enclosure /> tag above. An empty tag describes attribute specifications. In this case, the file location, its size, and the type of file it is.
2. Tags are case sensitive so you can’t have <TITLE>My Program</title>
3. Ending tags always have a slash like this </title>
4. The information between tags is called an element.
5. It’s important to follow the proper pattern and nesting.

Before using the podcast, you must upload the mp3 file and the RSS file to a web server, and validate It. To validate or make sure your RSS File is written correctly, go to http://rss.scripting.com/ and type in the address, or URL, of where you uploaded your RSS file. In our example: http://video.conncoll.edu/podcast/podcast1.xml

When you press the VALIDATE button, it will test your RSS feed and tell you if it is going to work. If you get an error message then you have made a mistake in syntax, tags, etc. Check your RSS file in your text processor, one little error will render the file useless.
Once your podcast has been validated, you can provide the address of your RSS file to anyone who wants to subscribe to your podcast.
In our example it would be: http://video.conncoll.edu/podcast/podcast1.xml

For more information

The RSS 2.0 Specifications are at http://blogs.law.harvard.edu/tech/rss
Good primers on RSS are at
http://www.eevl.ac.uk/rss_primer/
http://searchenginewatch.com/sereport/article.php/2175271
http://www.rss-specifications.com/
http://www.w3schools.com/rss/default.asp

To create RSS files for podcasting, see
http://podcastingnews.com/articles/Understanding_RSS_Feeds.html
http://www.rss-specifications.com/rss-articles.htm

Here is a good introduciton to XML: http://webdesign.about.com/library/xml/bl_xmlclassindex.htm?terms=learn+xml

End-users can subscribe to the podcast with an application like iTunes. In iTunes, select Podcasts in the left menu, then go to Advanced>Subscribe to Podcast, and enter the above address. iTunes will download the latest audio files in the podcast. Older files in the feed or channel can be downloaded by pressing the Get button. Users can listen to the “podcasted” audio file later, when it is convenient, or move them to their iPod.

The podcast aggregator (iTunes) regularly checks to see if the podcast (RSS file) has changed. If new audio files are included in it, they will automatically be downloaded.

There is other podcast aggregator software, but iTunes is the most popular. If you try to subscribe to the podcast with a regular RSS reader, like NetNewsWire, you may not be able to hear the audio. There is RSS feed creation software, such as FeedForAll (PC and Mac), which allows users to easily create, edit and publish podcasts without knowing any RSS or xml. There are podcast hosts, here you just fill out a simple on-line form, upload your audio files, and your podcasts are created and published for you. Finally, there are podcast directories, where you can list your podcasts for others to find.
For a list of many of the above resources, see the links in Podcasting News and Podcasting Tools.

For a podcast of the first-ever Academic Symposium on Podcasting, held at Duke University on Sep. 27-28, 2005, in iTunes go to Advanced>Subscirbe to Podcast and enter: http://dukecast.oit.duke.edu/podcasts/rss/11

To see videos of the Symposium, in your web browser, go to
http://isis.duke.edu/events/podcasting/webcast.php

For links to iPods in education:
http://ipod.gcsu.edu/
http://www.duke.edu/ddi/ipodfye.html
http://www.addysg.org.uk/ipodined/news.php