How to convert series of MP3 to a M4B in a batch

To concatenate the MP3s to an M4B, you could use ffmpeg. Download a recent version, then run:

ffmpeg -i "concat:input0.mp3|input1.mp3|input2.mp3" -c:a libfdk_aac -b:a 64k -f mp4 output.m4b

Your ffmpeg might not have fdk_aac enabled; if that's the case, you can try using

• -c:a libfaac (high quality)
• -c:a aac -strict experimental (decent quality, but use higher bitrates)
• -c:a libvo_aacenc (rather bad quality)

See the AAC encoding guide for more info.

If you want to use neroAacEnc instead, you could use:

ffmpeg -i "concat:input0.mp3|input1.mp3|input2.mp3" -f wav - | neroAacEnc -if - -ignorelength -q 0.3 output.m4b

Neither of these will add chapter metadata, I'm afraid.

If you're a Mac user, try Audiobook Binder http://bluezbox.com/audiobookbinder.html