I'm looking for a good software I can use to turn nonfiction e-books into audiobooks. Doesn't have to accept pdf input, but that would be a convenient feature. Post inspired by Speechify, but I want to do it ethically. Free open source software, running on my own computer, not some datacenter in what used to be the Amazon. Clear speech quality is the most important metric to me beyond that, performance isn't much of an issue. I'd be happy with something I have to leave running in the background for a few days to get good results.

Fun fact: I tried looking for a community to put this question in dbzer0, because they love AI, and there wasn't one! I thought for sure they'd have some kind of general AI community where I could ask for a TTS recommendation, but no. It's literally just image generation over there. Thanks programming.dev.