4 ms·

Show HN: M4b-tool – a tool to merge, split and chapterize audiobooks

48 points by sandreas 7y ago

em-bee 7y ago
this looks useful. i wonder how accurate it can detect chapters. i have been doing this work manually with audacity. and while the silence detector got me quite far, there always was some manual post processing to do because sometimes there were long silences within chapters or the chapter break was shorter than the others...
- sandreas 7y ago
  Chapter detection is one thing that I'm working on. The speech detection thing is promising, there is a log of work to do for this. Especially non-english languages are difficult. I'm also working on a online platform in my free time to share manually crafted chapter sets via api (like freedb), but I'm not sure that it will ever go online :-) I won't give it up either...
  - schemathings 7y ago
    I have sort of an opposite wish for the chapter detection feature. I'm a big fan of podcasts that tell a story per season or whatever you want to call it. Lot's of them have an intro ad for an indeterminate period of time and signal the beginning of the episode with an intro blurb usually voice over of 'welcome to ..' with some background music. I really don't mind listening to the ads the first time through but would love to save whole seasons without the leader ads as an M4b file - I've thought about writing this in the past, just haven't gotten to it. The ability to detect those points in a series of mp3s and bundle them up into an m4b would be super useful in my book.
    - sandreas 7y ago
      Nice idea... perhaps i will try to build this feature more generic and instead of only a chapter detection feature i will add a plugin interface, so that hooks could be defined for merge, split or chapter... But this is far far in the future ;)
crowbahr 7y ago
Very cool. This should integrate well into my ongoing audiobook hacking work. Building my own personalized shell scripts to interact with my library is fun!
- sandreas 7y ago
  Glad you like it. The batch mode together with the docker image and the --jobs parameter was a huge improvement to convert a bunch of audiobooks, even if there is much room for more.
aasasd 7y ago
I'm curious: what players do people use so that they feel the need to merge an audiobook into a single file? With VLC, the accuracy of my aim on the time bar would become nonexistent. Just two days ago I've finally whipped up a script to split books, and not by chapters but into 10-minute chunks.
- sandreas 7y ago
  Mmh perhaps a nice idea to extend m4b-tool to split it into fixed length chunks. Should be not too complex :-) I personally use iTunes with a good old ipod nano, but all Apple products support this type of file. But there are also many good Android apps, that support m4b. Even VLC supports chapters :-) I think the advantages are: - Smaller files than mp3 / better Quality per bitrate - Mp4 / m4a/ m4b is a more versatile format (more tags, chapter, a cover per chapter, etc.) Disadvantages: - Less common (less hardware player support - e.g. car audio) - Less software players support it But for my needs it is way better than having a bunch of mp3 files... Different strokes for different folks ;)
- dewey 7y ago
  I use Apple Books and it works well with chapters so I usually create the books with https://www.splasm.com/audiobookbuilder/ https://www.splasm.com/audiobookbuilder/
  - sandreas 7y ago
    Audiobookbuilder is nice, but commercial and only available on MacOS... Another open source alternative is Audiobook Binder (http://bluezbox.com/audiobookbinder.html http://bluezbox.com/audiobookbinder.html) - which is good and also comes with a command line utility, but it hat some GUI issues and is only available for MacOS. Another german project for Windows is http://www.audiobookcreator.de/ http://www.audiobookcreator.de/, which works, but it also did not fit my needs - i prefer auto command line merge instead of manual GUI interaction
schemathings 7y ago
Another poster cited "a cover per chapter, etc" as an advantage, but I don't see that capability in the linked tool (and I don't think it's part of the m4b format, which is a shame - the ability to change art per chapter or even more so, at points in the timeline, would really open some new uses e.g. saved lectures with slides).
- sandreas 7y ago
  There already is an issue for this on m4b-tool: https://github.com/sandreas/m4b-tool/issues/21 https://github.com/sandreas/m4b-tool/issues/21 In this issue there is a detailed description, how this can be achieved, but i did not manage to get it working with cover and audio (help wanted)

48 points by sandreas 7y ago

this looks useful. i wonder how accurate it can detect chapters. i have been doing this work manually with audacity. and while the silence detector got me quite far, there always was some manual post processing to do because sometimes there were long silences within chapters or the chapter break was shorter than the others...

sandreas 7y ago
Chapter detection is one thing that I'm working on. The speech detection thing is promising, there is a log of work to do for this. Especially non-english languages are difficult. I'm also working on a online platform in my free time to share manually crafted chapter sets via api (like freedb), but I'm not sure that it will ever go online :-) I won't give it up either...
- schemathings 7y ago
  I have sort of an opposite wish for the chapter detection feature. I'm a big fan of podcasts that tell a story per season or whatever you want to call it. Lot's of them have an intro ad for an indeterminate period of time and signal the beginning of the episode with an intro blurb usually voice over of 'welcome to ..' with some background music. I really don't mind listening to the ads the first time through but would love to save whole seasons without the leader ads as an M4b file - I've thought about writing this in the past, just haven't gotten to it. The ability to detect those points in a series of mp3s and bundle them up into an m4b would be super useful in my book.
  - sandreas 7y ago
    Nice idea... perhaps i will try to build this feature more generic and instead of only a chapter detection feature i will add a plugin interface, so that hooks could be defined for merge, split or chapter... But this is far far in the future ;)

crowbahr 7y ago

Very cool. This should integrate well into my ongoing audiobook hacking work. Building my own personalized shell scripts to interact with my library is fun!

sandreas 7y ago
Glad you like it. The batch mode together with the docker image and the --jobs parameter was a huge improvement to convert a bunch of audiobooks, even if there is much room for more.

aasasd 7y ago

I'm curious: what players do people use so that they feel the need to merge an audiobook into a single file? With VLC, the accuracy of my aim on the time bar would become nonexistent. Just two days ago I've finally whipped up a script to split books, and not by chapters but into 10-minute chunks.

sandreas 7y ago
Mmh perhaps a nice idea to extend m4b-tool to split it into fixed length chunks. Should be not too complex :-) I personally use iTunes with a good old ipod nano, but all Apple products support this type of file. But there are also many good Android apps, that support m4b. Even VLC supports chapters :-) I think the advantages are: - Smaller files than mp3 / better Quality per bitrate - Mp4 / m4a/ m4b is a more versatile format (more tags, chapter, a cover per chapter, etc.) Disadvantages: - Less common (less hardware player support - e.g. car audio) - Less software players support it But for my needs it is way better than having a bunch of mp3 files... Different strokes for different folks ;)
dewey 7y ago
I use Apple Books and it works well with chapters so I usually create the books with https://www.splasm.com/audiobookbuilder/ https://www.splasm.com/audiobookbuilder/
- sandreas 7y ago
  Audiobookbuilder is nice, but commercial and only available on MacOS... Another open source alternative is Audiobook Binder (http://bluezbox.com/audiobookbinder.html http://bluezbox.com/audiobookbinder.html) - which is good and also comes with a command line utility, but it hat some GUI issues and is only available for MacOS. Another german project for Windows is http://www.audiobookcreator.de/ http://www.audiobookcreator.de/, which works, but it also did not fit my needs - i prefer auto command line merge instead of manual GUI interaction

schemathings 7y ago

Another poster cited "a cover per chapter, etc" as an advantage, but I don't see that capability in the linked tool (and I don't think it's part of the m4b format, which is a shame - the ability to change art per chapter or even more so, at points in the timeline, would really open some new uses e.g. saved lectures with slides).

sandreas 7y ago
There already is an issue for this on m4b-tool: https://github.com/sandreas/m4b-tool/issues/21 https://github.com/sandreas/m4b-tool/issues/21 In this issue there is a detailed description, how this can be achieved, but i did not manage to get it working with cover and audio (help wanted)