Podcast

From Wikipedia, the free encyclopedia

Jump to: navigation, search

A podcast is a digital media file, or a related collection of such files, which is distributed over the Internet using syndication feeds for playback on portable media players and personal computers. The term, like "radio", can refer either to the content itself or to the method by which it is syndicated; the latter is also termed podcasting. The host or author of a podcast is often called a podcaster.

Contents

The term "podcast" is a portmanteau of the words "iPod" and "broadcast",[1] the Apple iPod being the brand of portable media player for which the first podcasting scripts were developed (see history of podcasting). These scripts allow podcasts to be automatically transferred to a mobile device after they are downloaded.[2]

Though podcasters' web sites may also offer direct download or streaming of their content, a podcast is distinguished from other digital media formats by its ability to be syndicated, subscribed to, and downloaded automatically when new content is added, using an aggregator or feed reader capable of reading feed formats such as RSS or Atom.

[edit] Trends and development

Main article: History of podcasting

The evolution and history of podcasting has revealed some noteworthy trends and developments that have arisen because of the nature, methods and terminology associated with podcasting.

[edit] Advocates and detractors

Some individuals have taken considerable effort to distinguish themselves as advocates or leaders in the realm of podcasting. In 2005, it was reported that Adam Curry had anonymously edited the podcasting entry on Wikipedia to remove credits from other people and to inflate his role in its creation.[3] The business model of Curry's podcasting network Podshow has since been criticised by many in the industry, and has been accused of exploitative practices in its dealings with independent podcasters.

[edit] Naming and intellectual property

The terms "Pod", "Podcast" and "Podcasting" have generated considerable friction between companies seeking to use the terms (or any of several variants) to distinguish their products and services.

For example, on February 5, 2005, Shae Spencer Management LLC of Fairport, New York filed a trademark application to register PODCAST for an 'online prerecorded radio program over the internet'.[4] On September 9, 2005, the United States Patent and Trademark Office rejected the application. The rejection notice cited Wikipedia's podcast entry as describing the history of the term.[5]

As of September 19, 2005, trademarks that capitalize on podcast include: Podcast Realty, GuidePod, PodGizmo, Pod-Casting, MyPod, Podvertiser, ePodcast, PodCabin, Podcaster, PodShop, PodKitchen, Podgram, GodPod and Podcast.[6]

On September 26, 2006, it was reported that Apple Computer started to crack down on businesses using the word 'pod' in product and company names. Apple sent a letter that week to Podcast Ready, which markets an application known as myPodder.[7] Lawyers for Apple contended that the term "pod" has been used by the public to refer to Apple's music player so extensively that it falls under Apple's trademark protection.[8] "POD."[9] On November 16, 2006, Apple Trademark Department returned a letter claiming Apple does not object to third party usage of "podcast" to refer to podcasting services and that Apple does not license the term.[10]

[edit] Variants

The concept of a podcast has evolved to such an extent that there are now several variants and niches in widespread use:

Autocast: Autocasting is an automated form of podcasting that allows bloggers and blog readers to generate audio versions of text blogs from RSS feeds. Autocasting software uses XML parsers, TTS (text-to-speech) engines, and audio conversion utilities to convert text blogs into audio files that can be placed on a blog for download, synchronized to a portable audio device, or played on a desktop computer.

Audioblog: Audioblogging is a variant on the blogging trend of online self-publishing, using audio to reach the audience instead of text used by traditional blogs. Audioblogs have similar form as blogs, using post-based entries cataloged by time and date. Autocasting is sometimes distinguished from Audioblogging because the latter does not necessarily originate from text-to-audio translation.

[edit] Mechanics

Podcasting is an automatic mechanism whereby multimedia computer files are transferred from a server to a client, which pulls down XML files containing the Internet addresses of the media files. In general, these files contain audio or video, but also could be images, text, PDF, or any file type.

The content provider begins by making a file (for example, an MP3 audio file) available on the Internet through some known Uniform Resource Identifier. This is usually done by posting the file on a webserver; however, BitTorrent trackers also have been used. The files may be available to the general public or may only be available to certain users.

An orange square with waves indicates that an RSS feed is present on a web page. Podcasts are often distributed through RSS.
An orange square with waves indicates that an RSS feed is present on a web page. Podcasts are often distributed through RSS.

The content provider then announces the existence of that file by referencing it in another file known as the feed. The feed is a list of the URLs by which episodes of the podcast may be accessed. This list is usually published in RSS format (although Atom can also be used), which provides other information, such as publish date, titles, and accompanying text descriptions of the series and each of its episodes. The feed may contain entries for all episodes in a series, but is typically limited to a short list of the most recent episodes, as is the case with many news feeds. Standard podcasts consist of a feed from one author. More recently, multiple authors have been able to contribute episodes to a single podcast feed using concepts such as social podcasting.

The content provider posts the feed on a webserver. The location at which the feed is posted is expected to be permanent. This location is known as the "feed URL" or "feed URI". The content provider makes this feed known to the intended audience.

A podcast specific aggregator is usually an always-on program which starts when the computer is started and runs in the background. It works exactly like any aggregator which checks each feed at a specified interval, such as every two hours. If the feed data has substantively changed from when it was previously checked (or if the feed was just added to the application's list), the program determines the location of the most recent item and automatically downloads it. The downloaded episodes can then be played, replayed, or archived as with any other computer file. Many applications also automatically transfer the newly downloaded episodes available to a user's portable media player, which is connected to the PC running the aggregator, perhaps via a USB cable.

The publish/subscribe model of podcasting is a version of push technology, in that the information provider chooses which files to offer in a feed and the subscriber chooses among available feed channels. While the user is not "pulling" individual files from the Web, there is a strong "pull" aspect in that the receiver is free to subscribe to (or unsubscribe from) a vast array of channels. Earlier Internet "push" services (e.g., PointCast) allowed a much more limited selection of content.

In March 2006 it was reported that 80% of podcast "episodes" are "consumed" on the PC onto which they are downloaded, i.e. they are never actually transferred to a portable player, or are deleted from the PC without being listened to.[11] 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 from an RSS feed before deciding to subscribe. For most broadband users, bandwidth is generally not a major consideration.

[edit] Other uses

Main article: Uses of podcasting

Podcasting's initial appeal was to allow individuals to distribute their own radio-style shows, but the system quickly became used in a wide variety of other ways, including distribution of school lessons, Church sermons,[12] official and unofficial audio tours of museums, conference meeting alerts and updates, and by police departments to distribute public safety messages.

[edit] See also

[edit] Syndication protocols

[edit] References

  1. ^ http://www.oup.com/elt/catalogue/teachersites/oald7/wotm/wotm_archive/podcast?cc=global
  2. ^ http://radio.weblogs.com/0001014/2003/10/12.html#a4604
  3. ^ Adam Curry Caught in Sticky Wiki from http://www.cadenhead.org/
  4. ^ PTO Letters of Protest: The "PODCAST" Paradigm from http://thettablog.blogspot.com/
  5. ^ Podcast trademark rejection cites Wikipedia from http://www.niallkennedy.com/
  6. ^ Podcast Trademark Gold Rush from http://www.podcastingnews.com/
  7. ^ http://www.podcastready.com/info.php?section=8&page=41
  8. ^ Apple cracks down on use of the word 'pod'
  9. ^ Podcast Trademark Controversy [Updated]
  10. ^ Apple letter from flickr
  11. ^ Dixon, Colin; Greeson, Michael. "Recasting the Concept of Podcasting: Part I." TDG Research. March 23, 2006. Accessed October 8, 2006.
  12. ^ http://www.map100.com/mapinteresting.php/podcasts-increasing-in-popularity/

[edit] External links

Wikibooks
Wikibooks has a book on the topic of
Look up podcast in Wiktionary, the free dictionary.
v • d • e
Podcasting
Types Audio podcasts · Blogcasting · Podcasting companies · Mobilecast · Video podcasts
Related articles Aggregator · Atom · History of podcasting · MP3 · Push technology · RSS · Social podcasting · Uses of podcasting

Retrieved from "http://en.wikipedia.org/wiki/Podcast"
Personal tools