David Penrose, in his article EDcasting asks “Whatever happened to SMIL?”. He suggests that SMIL could be renamed to something like “EDcasting”. In this article, I suggest that rather than being a competing “casting”, podcasts could be delivering richer experiences through the delivery of SMIL files rather than a simple MP3 or QuickTime file.
From the W3C page:
The Synchronized Multimedia Integration Language (SMIL, pronounced “smile”) enables simple authoring of interactive audiovisual presentations. SMIL is typically used for “rich media”/multimedia presentations which integrate streaming audio and video with images, text or any other media type.
So, David raises a good question. With the current Podcasting craze, where does SMIL fit in?
You’ve probably used SMIL even if you didn’t know it. Streaming audio/video that uses Real Player is using SMIL. For example, the Real Audio stream for the EMU album We Are His People uses SMIL to sequence five samples. Using the forward button in Real Player jumps to the next track. The SMIL file also tells the player to show a graphic and link that graphic to a web-page. The ABC Broadband news is another example of SMIL in use. The Streaming Media Tutorial on this site, explains how to create a simple SMIL file and provides links for learning more advanced techniques.
SMIL provides the ability to combine multiple multimedia sources into a single navigable file. From the RealSystem Production Guide (Chapter 6) some features of SMIL:
- clips can be of various file formats, and don’t need to be merged into one file
- clips can be located in various places (not necessarily on the same server)
- SMIL provides the ability to easily control the timeline of your presentation
- you can stream clips in multiple languages, and
- easily include ads in presentations
SMIL is a web standard just like HTML, XHTML and CSS.
So back to Podcasting. Podcasting seems to be generally about delivering an MP3 file via RSS 2.0. However, the RSS 2.0 specification doesn’t specify that the file must be an MP3 file. It just needs to be of a standard MIME type. Some have found that iTunes 4.9 gets this right and will also deal with QuickTime video in podcast feeds. So, SMIL should be a valid file format for delivery in a podcast – but I suspect that iTunes or Odeo may not know what to do with a SMIL file yet (iTunes’ podcast feature supports m4a, mp3, mov, mp4, and pdf source).
So… what’s my point… well, there’s a lot of background above, but the reason I write is this: HOW TO make Enhanced Podcasts from MAKE Magazine. This article describes the extra features that Apple allows podcasters to add to their podcasts for a more multimedia experience. Bascially, what Apple have done is taken the idea of SMIL (a XML file that creates a timed presentation from multiple files) and gone one step further to compile this file into a single MPEG file. Now this single file, when podcast, delivers chapter marked audio, images and links.
Why is this bad? Well, after all the work of groups like The Web Standards Project to get web designers using web standards and the major browser manufacturers supporting them correctly, along comes Apple promoting enhanced podcasts that only work in iTunes or on an Apple iPod, that require special tools and that seem to ignore the available SMIL standard.
We have looked at other formats and have started generating m3u’s in addition to rss podcast feeds. The trick with non-rss enclosure feed formats is that they have the default standard of streaming not downloading the media.
That said, we are planning on adding smil in addtion to atom, rss 2, rss 1, opml, oml, pcast, m3u, smil, xspf, and asx. So far we aren’t parsing all of those formats.
When people start publishing podcasts in those formats we will look at importing and supporting them.