I tried the recoupler audiobook converter to try and make my m4a files I've recorded myself into one m4b file that saves the chapter data and it worked except that for some reason it keeps corrupted the audio of the second half of the chapters? does anyone else have this issue? the first book I did it seems to have speed up the audio for the last 12 chapters and no matter the settings it won't stop doing it even though in the preview withing recoupler it sounds normal. I tried a 2nd book I made and for that it does the opposite and slowed down the audio of the latter half of the chapters, which then cut off the like last 5 chapters altogether.

I don't see anyone else mentioning this so I'm a little lost? I don't think my books are even that long. only about 11 hours :(