The Audio-Insert Offset Problem

There are a number of features and applications that need to know where sounds are in the middle of MP3 files. For example:

  • Audio search finds words and phrases in audio files and keeps track of where they are.
  • Our own Clip feature likewise works on the basis of offsets by time.

These are great features, but they’re plaugued by another new development: they dynamic assembly of MP3 files to include promos, commercials, etc. The problem is that when MP3s are re-assembled with components of different lengths, any previously identified sections will now be earlier or later in the file than previously determined. In other words, if a show is reassembled and therefore made longer or shorter, the location of a clip or segment will move and the search engine or clip feature will return incorrect results.

I’ve been working on a solution to this problem, and although it isn’t perfect yet — and maybe never will be — I want to get it out there to see if others would be willing to support it. We need buy-in from those who assemble shows or insert spots, and we need buy-in from the audio search engines as well.

My idea is to place into an ID3 frame information that will allow search engines and clip processors to understand what has been inserted or removed from the file so that these tools can deliver consistent results. Some possibilities include:

  • ID3 “Event Timing Codes” (ETCO frames)
  • ID3 “Position Synchronisation” Frame (POSS frames)
  • A custom ID3 frame

I haven’t figured out how POSS frames work, so they may have no relevance whatsoever. But one way or another, my idea is to somehow put offset information into ID3 frames, which can then be updated when the position of components within an MP3 file are changed.

Podcast Academy 2: A Huge Success

We filled the hall with 160 ehnthusiastic students for Podcast Academy 2, at and co-produced by Boston University. Thanks to the support of an amazing team at BU, there are already many online resources:

Don’t forget: The next Podcast Academy (PA3) is just a few weeks away, June 15-16 at Yahoo! in Santa Clara.

The Future of Public Media

There’s an interesting discussion underway on the web site of the Association of Independents in Radio (AIR), hosted by Stephen Hill. Great questions/comments in particular by Barry Rueger of My most recent post to the discussion:

Barry’s questions and the implicit answers are right on target. I believe this is a classic case of Clay Christensen’s Innovator’s Dilemma in that the established players can only perceive the change from their own perspective. Stations and networks still (and may always) see the Internet as something that is happening to them or as a new opportunity to extend what they do today. Christensen suggests they can’t escape this perspective.

Listeners and viewers, on the other hand, aren’t limited to that perspective. They see public media as just one of the many types of content they can reach using their preferred access technology. It’s not so much “How can I hear my favorite program?” as much as it’s “What is there to hear on the Internet?” Substitute “on my iPod” or “on my TiVo” or anything else. The audience is picking the platform first and the content second.

The long-tail phenomenon means that listeners/viewers have access to content that is much more interesting to them than what can economically be delivered by ‘broadcast’ transmitters. The economics of media are shifting rapidly from the fat head (my term) to the long tail. The size of the audience is relatively constant, but there will be more choices and a smaller audience for each program. We can’t fight this; we must embrace it. Lower production budgets and profits are an unavoidable consequence. Success will come to those who recognize this and can find ways to produce and distribute programs at a much lower cost. The Citizen Journalism movement is the extreme end of this spectrum.