RSS Feeds
Podcasting is a process where digital multimedia files are
downloaded from the Internet. A "subscription"
automates the download process, utilizing XML files containing
the Internet addresses of the media files. Most podcasts
are audio or video files, but they can also be images, text, PDF,
or any file type.
Podcasters make files (for example, MP3 audio) available
on the Internet by uploading their content to a Web server,
which gives that file a Web address (URL). Podcasters then
promote their podcasts, making them available on a subscription
basis using another file called a "feed." The feed is a list of the
URLs for each episode of the podcast series. RSS is the
most common format (although ATOM is also used). The RSS
feed also
provides descriptions and other information about the podcast
series and each episode.
The feed may contain entries for all episodes in a series,
but it is typically limited to a short list of the most recent
episodes. Standard podcasts consist of a feed from one author.
The podcaster posts the feed on a Web server. The location
(Web address, URL) at which the feed is posted should not change. This location is
known as the "feed URL." Podcasters promote podcasts by
making this feed available to the intended audience.
A "podcatcher" (podcast specific aggregator) is usually an
always-on program which starts when the computer is booted-up and
runs in the background. It works exactly like any aggregator
which checks RSS feeds at a specified interval, such as every
two hours. If the feed data has substantially changed from when
it was previously checked (or if the feed was just added to the
application's list), the podcatcher/aggregator software determines the location of the
most recent item and automatically downloads it.
The downloaded episodes can then be played, replayed, or
saved like any other computer file. Some podcatching software also
automatically transfers the newly downloaded episodes
to a user's portable media player, which can be connected to the
computer via a USB cable or Firewire.
The publish/subscribe model of podcasting is a version of push
technology in that the information provider chooses files
to offer in a feed and the subscriber chooses among available
feed channels. The user is not "pulling" individual files
(manually downloading) from the Web. The media is being
"pushed" via an automated download. The user is free to
subscribe to (or unsubscribe from) a vast array of channels.
In March 2006 it was reported that 80% of podcast episodes are
"consumed" on the PC onto which they are downloaded p
they
are never actually transferred to a portable player or are
deleted from the PC without being listened to.
To conserve bandwidth, users may opt to search for content
using an online podcast directory. Some directories allow people
to listen online and become familiar with the content provided
by RSS feed before deciding to subscribe. This saves bandwidth
because nothing is automatically downloaded - users just select
individual files that are of immediate interest. For most
broadband users, bandwidth is generally not a major
consideration. Automated downloads are becoming very
popular.
RSS is a family of Web feed formats used to publish
frequently updated content such as blog entries, news headlines,
or podcasts. An RSS document, which is called a "feed", "web
feed", or "channel", contains either a summary of content from
an associated web site or the full text. RSS makes it possible
for people to keep up with their favorite web sites in an
automated manner that's easier than checking them manually.
RSS content can be read using software
called an "RSS reader", "feed reader" or an "aggregator". The
user subscribes to a feed by entering the feed's link into the
reader or by clicking an RSS icon in a browser that
initiates the subscription process. The reader software checks the user's
subscribed feeds regularly for new content, downloading any
updates that it finds.
The initials "RSS" are used to refer to the following
formats:
- Really Simple Syndication
(RSS 2.0)
- RDF Site Summary (RSS 1.0 and
RSS 0.90)
- Rich Site Summary (RSS 0.91)
RSS formats are specified using XML, a generic specification
for the creation of data formats.
The
following is the source code for an XML file.
Those items in
navy blue are Optional iTunes Friendly tags.
<?xml version="1.0" encoding="UTF-8"?>
<rss xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd"
version="2.0">
<channel>
<title>Title of Your Podcast Series</title>
<description>Use a short text description of your podcast
series. Be sure to use appropriate keywords and terms that
will help people find your podcasts.</description>
<link>http://www.yourURL.com</link>
<language>en-us</language>
<copyright>Copyright 2008</copyright>
<lastBuildDate>Sat, 12 Jan 2008 11:30:00 -0500</lastBuildDate>
<pubDate>Sat, 12 Jan 2008 11:30:00 -0500</pubDate>
<docs>http://blogs.law.harvard.edu/tech/rss</docs>
<webMaster>email@webpage.com</webMaster>
<itunes:author>email@webpage.com</itunes:author>
<itunes:subtitle></itunes:subtitle>
<itunes:summary></itunes:summary>
<itunes:owner>
<itunes:name>your
name</itunes:name>
<itunes:email>email@webpage.com</itunes:email>
</itunes:owner>
<itunes:explicit>No</itunes:explicit>
<itunes:image href="http://URLofyourimage.jpg"/>
<itunes:category
text="choose category">
<itunes:category
text="choose catagory"/>
</itunes:category>
<item>
<title>Title of the podcast episode within your series</title>
<link>http://www.yourURL.com</link>
<guid>http://yourpodcastweb.com/mediaURL.mp3</guid>
<description> Short description, using appropriate keywords, to
tell people what this episode is about. Include the URL
for your podcast's homepage too. This is also a good place
to post notes and specific
links referenced during the podcast.</description>
<enclosure url="http://yourpodcastweb.com/mediaURL.mp3"
length="10531000 type="audio/mpeg"/>
<category>Podcasts</category>
<pubDate>Mon, 14 Jan 2008 11:30:00 -0500</pubDate>
<itunes:author>email@website.com</itunes:author>
<itunes:explicit></itunes:subtitle>
<itunes:summary>same as explicit above</itunes:summary>
<itunes:duration></itunes:duration>
<itunes:keywords></itunes:keywords>
</item>
</channel>
</rss>
XML Tags for RSS Feeds
Let's review this set of codes which begins with:
<?xml version="1.0" encoding="UTF-8"?>
<rss
xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd"
version="2.0">
Copy and paste this first 2
tag lines
exactly as they are - there is no need to edit them and any changes
will undermine the standard we are working with.
Next comes the "Channel"
and within that an "Item" or "Items." The Channel and the Item
require a Title, Description and a Link. With the Item
requiring the "Enclosure." For All items in
red please see this useful
iTunes
Tutorial
The Channel section starts with <channel>
Notice how these codes
(called "tags") are paired. First you have
<channel>. Near the end of
the file (after your last Item) you will have </channel>. Be
sure to follow this format exactly.
<title>Title of Your Podcast Series</title>
As you would expect,
this is the title. The <title> &
</title> Mark the begining and
end of your title respectively. In the middle you
put the title for your podCasts, typically this is also the
Title for your website.
<description>Use a short text description of your podcast
series. Be sure to use appropriate keywords and terms that
will help people find your podcasts</description>
Between the tags <description> and </description>, insert a
detailed description for all your podcasts. The detailed
descriptions of specific podcasts will be inserted later, in the
Item section.
<link>http://www.yourURL.com</link>
This is link (URL) to your
main site.
Up to now the first three categories were mandatory, the next
few are optional but highly recommended as they give some
additional information to the aggregators out there.
<language>en-us</language>
If you are in the US and
podCasting in English, use this example. Check this link
other language options.
<copyright>Copyright 2008</copyright>
Use the current year's date.
<lastBuildDate>Sat, 12 Jan 2008 11:30:00 -0500</lastBuildDate>
<pubDate>Sat, 12 Jan 2008 11:30:00 -0500</pubDate>
Insert the date and time of
the last change to your podcasts between these tags. The
"-0500" refers to GMT time. Be sure to use the following
formats for days and months:
Days
Mon
Tue Wed Thu Fri Sat Sun
Months
Jan Feb Mar Apr May Jun Jul
Aug Sep Oct Nov Dec
The next tag documents the source used to create an RSS feed.
Copy and paste our example.
<docs>http://blogs.law.harvard.edu/tech/rss</docs>
The last bit of information relating to the Channel is
the email address of the person responsible for the technical
aspects of the feed and podcast.
<webMaster>email@webpage.com</webMaster>
Note that the dates relating to when series are updated
or published will change, but the rest of the information in
the "Channel" section will probably remain the same.
The episodes in a podcast series are called "Items".
The newest item goes on the top of the "Items" listing. Start by inserting the title of your episode between the <item>
and </item> tags.
<title>Title of the podcast episode within your
series</title>
With iTunes this title will replace
the title in your ID3 tags. And will scroll across the screen
when being played on an iPod.
<link>http://www.yourURL.com</link>
This is the link for the
"homepage" or blog that hosts and
supports your podcast series. This is not the link to the media
file for an "Item" or episode. This is a Web or blog page you create and maintain
to supplement and host
your episodes. Use this page to post notes, resources, and
links to support your podcasts.
<guid>http://yourpodcastweb.com/mediaURL.mp3</guid>
This tag is required to have
a feed, validated using a validator service like
feedvalidator.org.
You can use the URL for the episode featured in this item
section.
<description> Short description, using appropriate
keywords, tell people what this episode is about.
Include the URL for your podcast's homepage too. This is
a good place to post
notes and any links referenced during the podcast.</description>
Next comes an important part,
the enclosure category is
unique and note that it DOES NOT have a pair of "<enclosure>"
and "</enclosure>" at the beginning and end. There are 3 parts
to the enclosure category.
<enclosure url="http://yourpodcastweb.com/mediaURL.mp3"
length="10531000 type="audio/mpeg"/>
- "url=" File location,
this is the same as that for <link> directly above except with
placed with " ".
- "length=" size of your
media file in bytes.
- type="audio/mpeg" the
format you use, this example is for audio format, just copy
and paste this.
The " " marks are very
important. The first two parts change for each item you add.
The "type" item will not change for audio and mpeg
video files..
For other media file
formats, use the
following templates for the enclosure tag depending on the format of the video:
.MOV
<enclosure url="http://yourpodcastweb.com/mediaURL.mov"
length="1182000" type="video/quicktime" />
.WMV
<enclosure url="http://yourpodcastweb.com/mediaURL.wmv"
length="5381000" type="video/wmv" />
.MP4
<enclosure url="http://yourpodcastweb.com/mediaURL.mp4"
length="63842000" type="video/mp4" />
PDF
Podcasts can even distribute .pdf documents (printable, downloadable documents)
For an example, please see
Mr. B's Beginning Algebra Web
and his
Algebra Connections
newsletters in the Breitlinks Podcasts section of this Web.
the
enclosure tags for these documents is:
<enclosure url="http://yourpodcastweb.com/filename.pdf"
length="255457" type="application/pdf" />
Next is the category tag - for podcasts, just enter:
<category>Podcasts</category>
The last non-iTunes
category in an "Item" is the publication date. Again the time
calculation will be the same as in the "Channel" section above.
<pubDate>Sat, 12 Jan 2008 11:30:00 -0500</pubDate>
Now, we need to indicate the end of this item, use an
"item" closing tag like this:
</item>
Repeat this item section for each episode (item) in your series
(channel). When you are done, you also need to indicate
the end of your series (channel) information by using a "channel
closing tag like this:
</channel>
Finally, we need to indicate that the XML file we have
created is done with one last closing tag:
</rss>
This is everything you need to create your own .XML file -
you can copy and paste the example above into notepad, enter
your data, and save as an .XML file. Here's a link to an
example online that you can right click and "save linked file as" to your
desktop and then you can edit it with a text editor.
http://www.breitlinks.com/feed.xml
Make sure you keep the .xml extension on the file when you save
it (not .txt). This demo
feed DOES NOT include iTunes tags.
Once completed, you can upload your .xml file to your website.
Then, check it to make sure it is valid and can be read by the
aggregators out there. Here are 2 free validating
services:
From there enter your RSS feed to be validated. Be sure
you leave in the "http://" (hint: make sure you don't
double it up as there is already a "http://" inserted when you
arrive at the validator.
If everything is "good to go", it comes back with:
"Congratulations -- the RSS feed validates!"
Now you are ready to add your podcast to the different
directories out there by submitting the URL to your validated
feed - good luck and have fun with your podcasts!
There are additional tags to add to your RSS feed in addition
to the RSS information to make your feed "iTunes friendly." You do not need
to add these takes if you are not going to post your RSS feed at
iTunes. Teacher-created podcasts do not have to be listed
at iTunes.
Keeping this information always up-to-date can be a
challenge. Rather than try to recreate iTunes extensive
resources here, it will be easier for you to just click over to iTune's
detailed and well-documented resource page,
Technical Details: Submissions and
Feedback Processes
Review the details for iTunes submissions if you would like
to add your RSS feed there - be sure it is "iTunes friendly."
If you are not going to post your podcast at iTunes, then there
is no need to add these extra tags.
Maintaining a CURRENT PODCAST Link
Many podcasters maintain a special link to their "current"
podcast. The idea is to always have a static link that
does not change and always point to the latest episode in your
podcast series.
This is created by always uploading 2 copies of the current
podcast.
- One has a unique name for the RSS feed. For example,
this one might be: yourweb.com/podcasts/12-27-07.MP3
- The other always has the same name and is overwritten over
the last current podcast.
This one might be named: yourweb.com/podcasts/currentpodcast.MP3
and this is the one that would be linked to from an icon or
text-based "Current Podcast" link.
This allows people to access your series
like any other podcast with a feed, yet also lets people link
to, bookmark, email, or check a static URL that will always feature the
latest podcast you have to offer.
More Resources About RSS Feeds
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