Very cool, and nice work on this! I used to record wikipedia's articles in audio format to help those who had trouble reading, so I'm a huge fan of anything that makes public domain work more accessible.
As a rabid audiobook consumer, I do have a couple of suggestions.
An easy one - currently you only use the Onyx voice from OpenAI. I'd recommend that at the very least you match the gender of the voice to the gender of the author. I find this is pretty common with published audiobooks, and I find it helps bring out the tone of the author more.
A harder one - most great audiobook narrators change their voice depending on the character speaking. If you really wanted to go in depth here, parsing the text by character and matching them to a voice would go a long way in making these more listenable. It would be fairly straightforward (albeit more expensive) to parse these books with an LLM and ask it to add inline markdown for the right voice options for each speaking character.
Given a great narration in one language, have a model annotate the tone and emotion of the narrator for each sentence, and re-apply these emotions to the voice synthesis for a target language, on the translated version.
Narration/recitation is such an orthogonal axis to the story and literary style, and an integral part of the experience.
> I'd recommend that at the very least you match the gender of the voice to the gender of the author.
I prefer the voice to match the protagonist. Or better yet an audio play with the narrator voice plus a voice matched to each speaker.
This is the kind of bikeshedding that AI text-to-voice can make moot. We can all have it our own way. That's an argument for generating the voice just in time rather than as a batch. But as long as such tools aren't ubiquitous this batch is a great public service.
> an audio play with the narrator voice plus a voice matched to each speaker
Oh, please don't! I find this extremely disorienting! When I am listening to an audiobook, I am not listening to the voice. I am transported, envisioning another world, and changing voices often breaks the immersion by forcing me to re-calibrate to their cadence, tenor, accent, etc.
Totally fair. Solo dev is hard, and those priority choices are always a challenge. Remember that you have more context than anyone else suggesting things here - I'm sure that 3mo delay is for a reason. Great work so far!
One of the other comments mentioned matching voice to protagonist, which would fit your example for Harry Potter.
There are likely many factors that go into selecting the right voice here - my main point is the same voice shouldn't be used for all books. It's likely a simple heuristic is better than "male voice for all", though no approach will be perfect without the opinion of the author, which isn't available unfortunately.
Indeed, voice matching to book "by some magic metric" is the way to go.
My comment wasn't entirely clear, it was the "voice matched to author gender" part that prompted a response.
In the great scheme of thing any voice reading aloud is an advance for people that require or like to hear books read out, improvements can come on a per book basis.
The end goal is likely a mix of bespoke readings by gifted voive readers (Fry) and guided "selectable AI voice" readings that can do can do clear and correct pronunciation and pacing with the voice of Jamie Erl Jonas (totally not James Earl Jones), Skarlat Johnson, or that Chipmunk character.
Disagree, the narrator for Harry Potter has always been a male in my head. I don’t think people read the book in the tone of the author, more in the tone of the main protagonist.
The most common versions of the audiobooks are narrated by Jim Cook and Stephen Fry.
> I don’t think people read the book in the tone of the author
People certainly do in some instances, but an interesting thing about generated content going forward is folks will likely have the ability to choose on demand.
As a rabid audiobook consumer, I do have a couple of suggestions.
An easy one - currently you only use the Onyx voice from OpenAI. I'd recommend that at the very least you match the gender of the voice to the gender of the author. I find this is pretty common with published audiobooks, and I find it helps bring out the tone of the author more.
A harder one - most great audiobook narrators change their voice depending on the character speaking. If you really wanted to go in depth here, parsing the text by character and matching them to a voice would go a long way in making these more listenable. It would be fairly straightforward (albeit more expensive) to parse these books with an LLM and ask it to add inline markdown for the right voice options for each speaking character.