The 4 Types of Podcasts

We recently conducted a workshop on engaging distance education students with podcasting, and there were several questions, and some confusion about the different types of podcasts.  Thankfully much of the hype around podcasting has died down and is now focused on Twitter, so there is an opportunity to take a good look at podcasting to uncover any potential benefits to teaching and learning.  Although marketing departments and techno-hypers like to throw around many different acronyms and terms for podcasting; about.com has a very long list of any potential combination of a “word+casting” that possibly exists.  We like to tell our clients there are essentially four types of podcasts.

1. Audio podcasts are (yes) audio only.  They are generally mp3 format (can also be AAC) and may be the most common type of podcast.  Audio podcasts (in mp3 format) are the most compatible with all computers and portable media devices.  Positive aspects of audio podcasts include their relatively small file size, usually less than 10MB depending on length, and that they are relatively easy to create.  A negative aspect of this type of podcast is that the content or message is limited to audio only.  However depending on the content, the audience, and the purpose that may be all that is necessary.
2. Video podcast is a term used for the online delivery of video content.  The term is used to distinguish between podcasts which most commonly contain audio files and those referring to the distribution of video.  However, the term Podcast has from its inception described the distribution of digital media files, including video and audio via RSS enclosures and hence the terms video podcast, vodcast or less commonly vidcast. are redundant. (wikipedia, July 7, 2009)  Video podasts are rapidly becoming a popular format for traditional media and television networks.  For example, the NBC and CBS Nightly News are just two of the video podcasts that have been created to “re-purpose” content, and most shows on PBS and NPR are available as either audio or video podcasts.

   Unlike an audio podcast, creating a video podcast is like any other video production project and requires more production and planning time to produce.  In regard to file size, downloading a video podcast requires a high bandwidth connection because they are large files (typically upwards of 100 MB each depending on the length).  The preferred format for video podcasts is typically .m4v or mp4 H.264, and they can be created and consumed by both Mac and Windows users.

3. Enhanced podcasts are a somewhat unique type of podcast that combine audio podcast with synced images, similar to a narrated slideshow.  They often contain multiple still images that change like a slideshow, and you can also add live URL links to Websites as well as chapter markers to skip around the podcast.  Technically, enhanced podcasts are audio files in .m4a format (also known as mp4 or AAC format), with a layer for embedding the synced images.  The enhanced podcast format has been adopted by Apple and Sony, and are essentially playable on any Mac or Windows computer that has iTunes installed.  Enhanced podcasts do not currently play in Windows Media Player.  A benefit of enhanced podcasts is that they present both visual and audio content, but the file size is nearly the same as a typical audio-only podcast, and exponentially smaller than a video podcast!  At the time of this blog post enhanced podcasts can really only be created on a Mac computer with Garageband (for now).
4. A Screencast is a digital recording of computer screen output, also known as a video screen capture, often containing audio narration. Although the term screencast dates from 2004, products such as Lotus ScreenCam were used as early as 1994. Early products produced large files and had limited editing features. More recent products support more compact file formats such as Adobe Flash, and mp4/H.264, and have more sophisticated editing features allowing changes in sequence, mouse movement, and audio. Just as a screenshot is a picture of a user’s screen, a screencast is essentially a movie of the changes over time that a user sees on his monitor (wikipedia, July 7, 2009).

Finally, it is important to note that you do NOT need an iPod to create or listen to podcasts! In fact a 2005 Bridge Ratings consumer survey found that over 80% of users simply listen to downloaded podcasts on their computer or laptop and the podcasts never make it to an iPod or other digital media device.