The jd3lib Blog

Wednesday, August 24, 2005

Enhanced MP3 Podcasts (Proposal)

This is a proposal for a "new" Podcasting file format. It's basicly an MP3 file with the same features as enhanced m4a podcasts introduced with Itunes but because it's mp3 it's playable on every Mp3 player. No need for two different files in the feed, one file format does it all. The advantage of this proposed new format is that the files will be playable on each and every MP3 Player out there. The file format is open and completely platform independent, no need for M4A itunes or a certain Chaptertool. M4A is a good new file format and this proposal doesn't want to fight this. M4A i the next generation but for now the Digital Audio Player marked has only one common divisor and that is MP3 no format is wider spread. So just as FM Radio and NTSC/PAL TV, MP3 is the format of choice if you want to get to the masses. Of course the market share of the IPod is high but the marketshare of players capable to play MP3 is higher then players capable of playing M4A simply because the IPod can play MP3 too. So here is the proposal, feel free to comment on it, tell me what you think development could start as a sourceforge project, writing a Java MP3 Enhancer Tool and a Tech Demo Player.

Proposal 1

  • Standard MP3 File with ID3v2 Tag
  • ID3v2 Tags used
    • TCOP for copyright information
    • TPUB for Publisher information
    • TCON for Content type/Genre set to "Podcast"
    • WOAF for the original URL to the file
    • WPUB for the feed URL
    • SYLT used for the Exact Chapter positions and markers to the APIC
    • unlimited numer of APIC frames for Pictures

Proposal 2

  • Standard MP3 File with ID3v2 Tag
  • ID3v2 Tags used
    • TCON for Content type/Genre set to "Podcast"
    • XPST for Podcast Payload
      The Podcast payload can be pretty much everything one can imagine I would propose a ziped file containing the following
      • an XML file with the markers and pointers to the images similar to the XML file created by the Chaptertool
      • the images as the original files

Proposal 1 vs. Proposal 2

The first proposed enhancement is using the already existing ID3v2 Tag specifications like APIC and SYLT the advantage here is that Generic MP3 Players not prepared for Podcasting might be able to parse parts of the Data leading to an enhanced experience eventhough there is no dedicated support for enhanced MP3s. The second propsal allowes to create enhanced mp3s fast an easy from a programmers fewpoint proposal two is way easier to implement and also to extend.


At 13/10/05 11:54, Anonymous Anonymous said...

Hi there have you started on this project, cause if you can pull this off, this can change everything. No longer will you need to play enhanced podcasts on ipods only.

But the question is, can a project like this really be possible to create?

Please let me what is your progress, or what you need to create such a project.


Marnny, England, UK

At 16/9/06 12:31, Anonymous Anonymous said...

There is a proposal for chapters in ID3v2 for mp3 etc at:

This is new extension and very flexible, but there's not much support for it yet. There is some software to create and read the new proposal at:

It usefully supports importing and exporting Apple's ChapterTool XML format.

The BBC are making an experimental enhanced mp3 (a copy of the Chris Moyles enhanced podcast that's in Apple's format) at:

Just need more players, creation tools and content for it to take off I suppose... :-/


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