Tagging Variable-Length MP3 Intros

We used to have an awesome excerpt/clip feature that I implemented after experimenting and discussing with Jon Udell. But when The Conversations Network started using an automated show-assembly system, we had to disable it. The reason was that our programs began to include intros that could change on a daily basis, and any reference to a specific time in an audio file might be be invalidated whenever the content of an intro was updated. As I proposed in 2006, I’ve now added the ID3 “ETCO” frame to the ID3 headers of all programs on The Conversations Network.

I hope to eventually reincarnate the clip/excerpt feature. In the meantime, I want to let people know it’s there, in case they want to use it or — wouldn’t it be great — adopt it as a standard way of documenting where the body of a program begins. Someone could even develop or enhance a Flash player that skipped all intros! I also hope it will be adopted by others such as SlideShare.net so that we can produce synchronized audio/slide presentations that support our variable-length audio-program intros.

For those who want to read our ETCO frames or write their own, the official syntax I’m using is as follows:

"ETCO"       Header for "Event Timing Codes"
$02          Absolute time, 32 bit sized, using milliseconds as unit
$03          Type of Event (mainpart start)
<32-bit int> Offset in milliseconds as a 32-bit 'synchsafe' integer

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