michael roth

I think mp3 separated by chapter would be ideal for most! .m4b is the traditional “audiobook” format.

If you guys ever desired to put it on audible.com here is a link talk about how they break down there proprietary files/formats. https://audible.custhelp.com/app/answers/detail/a_id/5128/~/what-is-an-audible-format%2C-and-how-do-i-choose-the-one-that-best-suits-me%3F

Also an interesting YT vid on making audiobook files:  

user57868172  michael roth

I ordered from the link, was short and sweet. Worked well. I think.