How to programatically combine two aac files into one?

Question

I'm looking for a cat for aac music files (the stuff iTunes uses).

Use Case: My father in law will not touch computers except for audiobooks he downloads to his iPod. I have taught him some iTunes (Windows) basics, but his library is a mess. It turns out, that iTunes is optimized for listening to podcasts and random songs from your library, not for audiobooks.

I would like to write a script (preferably python, but comfortable with other stuff too) to import his audiobook cds in a sane fashion, combining the tracks of each cd into a bookmarkable aac file (.m4b?) and then adding that to iTunes so it shows up in the audiobooks section.

I have figured out how to talk to iTunes (there is a COM interface in Windows, look for the iTunes SDK). Using that interface, I can use iTunes to rip the CD to aac format. It's the actual concatenation of the aac files I'm having trouble with. Can't find the right stuff on the net...

Answer 1

I haven't seen an aac codec library for python, but you could use wav files as an intermediary format.

You can pull the tracks off the cd as wav files, and then use the wave module to concatenate them into one large file, which could then be converted by itunes to aac. This may increase your processing time considerably because of the size of the data, but it would be fairly easy, and you don't need any external libraries.

Answer 2

The most powerful Python audio manipulation module out there seems to be Python Audio Tools. The download comes with CLI tools that would probably do everything you'd want to do, even ripping, so you can even get by with shell scripting the whole thing. The module itself is also pretty powerful and has a handy set of functions to manipulate audio files. If you want to stick with writing everything in python, you can possibly learn enough to do what you want to do after studying their CLI source code. Specifically they have a tool that just does audio file cat in any codec. (They do depend on FAAC/FAAD2 for AAC support, but that'd be true for every library you'll find)

Answer 3

Not programming related (well, kinda.)

iTunes already has functionality to rip as a single track (e.g. an audiobook.) Check this out: http://www.ehow.com/how_2108906_merge-cd-single-track-itunes.html

That fixes your immediate problem, but I guess people can keep discussing how to do it programatically.

Answer 4

I created a freeware program called "Chapter and Verse" to concatenate m4a (AAC) files into a single m4b audiobook file with chapter marks and metadata.

If you have already ripped the CD's to AAC using itunes (which you say you have) then the rest is easy with my software. I wrote it for this exact reason and scenario. You can download it from www.lodensoftware.com

After trying to work with SlideShow Assembler, the QT SDK and a bunch of other command line tools, I ended up building my own application based on the publicly available MP4v2 library. The concatenating of files and adding of chapters is done using the MP4v2 library.

There are quite a few nuances in building an audiobook properly formatted for the iPod. The information is hard to find. Working with Apple documentation and open libraries has its own challenges as well.

Best of Luck.