So the actual problem that I'm trying to solve is to read books via TTS on my phone and also read the same book as text at the same place.
Every ebook reader I've tried that does this sucks in various ways; I'll name them just to save y'all the trouble of suggesting them unless they've improved dramatically in the last few months: Moon Reader + Pro, Voice Dream (AKA "Reader" (really?)), FBReader TTS, @Voice.
The other thing is that running TTS seems to take some noticeable battery/CPU.
So I thought why not do the TTS in advance, save it as an audio file, read it in Pocket Cast, and have an ebook program be synchronized to the position I'm at in the audio file? I mean, there are programs that sync an ebook with an Audible file, right? Same thing, right?
The thing is, AFAICT the only thing that does this is Kindle/Whispersync. I can't figure out how to take advantage of this; seems like I could provide my own audio file to go with Kindle books, but do the Kindle books need to be specially marked? Does the audio file?
Maybe there are other apps or combinations of apps that can do this?
I'm highly technical, and while I've not programmed against Android I've programmed in perhaps 20 languages over my life and I'm sure I can figure it out, so writing actual code is an an option, but I have no idea where to begin; any thoughts?