Injecting ads into a podcast at exact timestamps sounds easy until your sponsor read lands mid-sentence. This tool finds natural break points using word-level timestamps and semantic scoring, then stitches in your rolls cleanly. It also transcribes episodes and generates show notes - and that transcription is what powers the midroll engine.
My Gnothi Series creates ongoing educational series and podcasts: describe a subject, and it researches, writes, and narrates episodes on a schedule.
This post explains the midroll injection engine I built for podcast production: placing sponsor reads, intros, and outros at natural breaks in an episode.
The engine takes episode audio and recorded rolls, then places the rolls automatically:
This is what makes it not suck. If you say "every 20 minutes," it doesn't blindly cut at 20:00. It finds 20:00 plus or minus ~5 minutes, looking for the best break point based on sentence boundaries and context shifts. The transcription gives us word-level timestamps, and a semantic scoring model identifies where you've actually finished a thought. So your sponsor read doesn't land in the middle of "and that's why transformers use atten--THIS EPISODE IS BROUGHT TO YOU BY--tion mechanisms."
After a mid-roll, the tool replays a few seconds of audio from before the break. So listeners get re-oriented. You know that feeling when an ad ends and you've completely lost the thread? This fixes that.
Change your rolls and every affected episode gets flagged as "stale." Re-process them in bulk. Swap out a sponsor, re-roll everything, done.
The tool also transcribes your episode (via faster-whisper), then an LLM generates a title, teaser, and full description from the transcript. Paste those straight into your podcast host or website. No more staring at a blank description field for 20 minutes after you just spent an hour recording.
The transcription also feeds the midroll engine - word-level timestamps are what make the smart break-point detection possible.
The engine handles one part of podcast production. Gnothi Series handles the ongoing show: researching, writing, and narrating episodes about the subject you choose.
Choose a subject and a schedule. Gnothi researches, writes, and narrates an ongoing series you can follow in your podcast app.