How to identify CTOC (Table of Contents) chaps from mp3

[eduo]

Hello!

When dumping the tags for a chapterized mp3, the resulting table doesn't seem to distinguish betwen entries that are part of a table of contents and parts that are not.

Is this by design or pending for development?

https://web.archive.org/web/20180730050242/http://id3.org/id3v2-chapters-1.0

[sandreas]

Thanks for pointing this out.

Is this by design or pending for development?

I read the chapter frame adendum specs (some time ago), but I did not notice, that there is a difference, that might be important. Inatldotnet while reading the metadata, there seems to be no possibility to distinguish:

ATL/Entities/ChapterInfo.cs

Maybe this is worth submitting an issue on atldotnet - I'm going to talk to @Zeugma440 about this.

May I ask, what you would need this for? I would love to have a real world use case to better understand this problem.

[eduo]

Hi!

The original chapter marker specification was originally designed for audiobooks. It didn't cover only proper chapters but also the audiobook equivalent of accompanying images and footnotes. It separated between one or the other by using the CTOC frames. Strictly speaking the table of contents could even contain multiple levels of depth to identify chapters and sub-chapters.

It is also used in this way in podcasts. A podcast may have four sections along an hour, but during those many images or links may be shown to support the audio. In Audiobooks it is used to show accompanying illustrations to the narration (unrelated to chapters themselves).

You can see in this screenshot a sample podcast file containing many entries that are not strictly in the TOC, as they are mostly logos and screenshots of companies and software being discussed (the checkbox column with the hamburger icon is the TOC one in this editor):

[sandreas]

Thanks for providing so much information. I don't think that this is already supported... Could you provide a sample file or link to this podcast? This would probably be enough to reproduce the issue. And the name of the software you are using in the screenshot would also be very helpful.

[eduo]

Gladly. Although the software itself might not be very useful. I use both "Forecast" and "Chapters", both of which are for Mac (mainly because Forecast intakes markers from audacity or logic pro, where I add them as I edit, and pre-fills those chapters placeholders for me).

A good mp3 to test this might be this episode (direct mp3 link)

It contains 8 chapters "proper" plus many links and artwork that popups up for the specified duration, with the link and link text specified.

[sandreas]

Awesome, thanks for providing these. I'll see what I can do here.