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Topic: How many chapters are allowed in M4B files? (Read 3843 times) previous topic - next topic
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How many chapters are allowed in M4B files?

Hi,

I encountered that some m4b files can only have max 255 chapters.

Not 100% sure, but I had old m4b files which used to have more than 255 chapters, like, say >300.

After changing some tags in the properties dialogue, those files show 255 chapters only,
and the length is summed up for the "rest" of the chapters.

Plese see screenshots.

Is there a setting to max out the number of chapters?

Re: How many chapters are allowed in M4B files?

Reply #1 –
I hope, this has not answered 100 times, but my search in the forums did not return any useful hits.

Re: How many chapters are allowed in M4B files?

Reply #2 –
If shown chapter count changed with editing of tags, you have found a bug. If you can send me a sample file with >300 chapters where chapter information get lost on retag, it would be most helpful.
Microsoft Windows: We can't script here, this is bat country.

Re: How many chapters are allowed in M4B files?

Reply #3 –
Quote from: Peter on
If shown chapter count changed with editing of tags, you have found a bug. If you can send me a sample file with >300 chapters where chapter information get lost on retag, it would be most helpful.
I sent you a PM. Hopefully it helps!

Re: How many chapters are allowed in M4B files?

Reply #4 –
Fixed in today's build, thanks for the details.

Chapters not actually gone from files - out of two chapter records available, one that supports only up to 255 was preferred.
Microsoft Windows: We can't script here, this is bat country.

Re: How many chapters are allowed in M4B files?

Reply #5 –
Seems to work here too :-)
Thank you very much!
Case closed.

Re: How many chapters are allowed in M4B files?

Reply #6 –
...on the other hand....

Now its not possible to change the TITLE-Tag anymore.

Any changes are reverted back to "001", "002", "003", "004".... until last chapter

Re: How many chapters are allowed in M4B files?

Reply #7 –
Added a short video/animated gif to visualize the new introduced bug.

 

Re: How many chapters are allowed in M4B files?

Reply #8 –
Known problem.

Long explanation coming up:

There are two standards for MP4 chapters that foobar2000 supports:

  • chpl
Easy to manipulate, but only up to 255 chapters.
  • QT chapter track
Can store virtually any number of chapters, but have to remux whole file to alter chapter list or chapter titles.

foobar2000 can only edit chpl chapters, with the ugly 255 entry limit. If your file has QT chapters, foobar2000 currently has no power to alter their contents. When retagging such files, chpl record is written with new titles but not actually read back when file has QT chapters with >255 records. I'll investigate making this more elegant.

For now, I recommend remuxing your file to Matroska, which will fix all of these issues. Use either mkvtoolnix or ffmpeg -i file.m4b -c copy out.mka
Microsoft Windows: We can't script here, this is bat country.

Re: How many chapters are allowed in M4B files?

Reply #10 –
I tested with preview 2024-08-14 and its not possible to successfully change title tags for files with only 167 chapters.

Same result as in the video above. Any changes are reverted back or overwritten to "001", "002", "003", "004".... until last chapter

I could reproduce this:
-my testing with only 1 tag did succeed. (tag was updated)
-my testing with only 15 tags succeeded too. (tags were updated)
-but as I selected all chapters via CTRL+A and changed all 167 title tags to "test" at once, the restult was "001", "002", "003", "004"....

I assume, this is not the expected behaviour.

Re: How many chapters are allowed in M4B files?

Reply #11 –
*bump*
behaviour of f2k v2.2 preview 2024-09-02 seems odd to me, when changing a m4b file with only 7 tracks.

I don't expect f2k to replace all my title tag changes with a generic "Kapitel" tag.

I made another "video" with a fresh install in DUI (simple playlist + tabs)

single editings of title tag seems to work (if not changeing all to the same tag)  but if I change them all at once, my changes are replaced by "Kapitel".