From Podcast to Audiobook
7/1/2026 1:52 pm | Share to: 
We had D&D last night and the group was talking about The Adventure Zone, a D&D podcast by the McElroy brothers and their father. It's over ten years old now and still going, but I particularly enjoyed the starting story arc for the podcast as they began playing D&D together.
After that discussion, I decided I wanted to go back and listen to it, but I wanted to get it as an audiobook on my phone. Mostly because it means I can hit play and my phone will track where I am and I don't have to navigate to sequential episodes, etc. Sure, I could do this with a playlist in the podcast apps, but then it's a one-time thing. This way, I have the entire run stored in my archives in an easy way to listen when I decide I want to again in ten more years.
Get all the MP3s, stitch them together into a M4b file using ffmpeg, and boom - you're good. Right?
Not quite. Turns out it is a little more complicated.
Ffmpeg is one of those tools which secretly keeps the internet afloat. It powers countless video and audio based programs and websites as a universal and powerful tool.
First surprise, the initial processing actually took all night. I knew it would take a while, just not really how long it would be.
This initial processing took nearly 8 hours to complete. That yielded nearly a 6 gig audio file. That size isn't shocking, it's a run of 70 episodes with a run time of 90 hours. I should have realized it would be this big as I was just literally taking the downloaded files and putting them all into one file with no conversions. I just didn't really think about it.
One thing to do to shrink these files is to decrease the quality of the audio. Default for podcasts is usually 128kps as the audio quality, but for audio that is just talking you can go down to 96kps or even 64kps with almost no notable difference. So, I reencoded it this morning at 96kps, which took a few more hours, and that took it down to less than 4 gigs in size. Still large but more manageable.
However, then I get it onto my phone and I use an open source audiobook app called Voice. And, despite it being in the folder the app monitors, I can't see it in the app. Which only leads me to believe there is something wrong with the metadata.
Metadata is the term for various "invisible" things on a file. For mp3s this is things like "title" and "artist," etc. But also things like a setting that confirms that this is an audiobook file. And so I think I'm missing something there.
I began exploring various tools and realized the easiest option may already be up and ready for me: Audiobookshelf. I run a self-hosted instance of it for managing my audiobook collection. And I do this for the same reason Sony deleting movies from customers is news: If I purchase something, I want to own it. And to do that means I need to have it without DRM and on my own file systems so someone elsewhere can't up and delete it. Thus I use Audiobookshelf to handle that management for me, and enable me to download them from the server onto my phone.
Additionally, it turns out that it actually has functions to do re-encoding that will hopefully will fix the metadata issues for me. As I write this it is in the midst of re-encoding, we'll see how long it takes and if it works!
