Why a podcast ad cannot be blocked
A browser ad blocker works because the ad arrives separately from the page, so it can be dropped on the way in. A podcast ad does not arrive separately. By the time the MP3 reaches you the sponsor read is part of the recording, the same waveform as the host’s voice, often recorded by the host in the same breath. There is nothing to block. The only way to get rid of it is to find where it starts, find where it ends, and cut that stretch out of the file.
That is the whole of what Feedcast does, and it is why it runs on a Mac rather than on your phone: transcribing and re-encoding an hour of audio is real work, and it has to happen before your player ever sees the episode.
Finding where the ad is
Feedcast looks in several places, and every one of them adds the breaks it finds.
- The show’s own chapters. Plenty of podcasts ship chapters and politely name one of them Sponsor, Ad or Werbung. Feedcast reads the chapters in the file or in the episode description and takes the ones whose title marks an ad.
- The transcript. Every episode is transcribed on your Mac. The text, never the audio, then goes to Feedcast’s server, where a language model writes the chapters and marks each sponsor read with its start and end. This is the step that works on any show, large or small.
- The publisher’s transcript. When a show publishes its own transcript, Feedcast compares it with your download. Ads stitched into the file at download time are not in the publisher’s text, so they stand out.
- Reads it has cut before. Feedcast remembers the sponsor reads it removed and finds the same read again when it comes back, in a later episode or in another show. Switch a read off in one show and it stays off everywhere.
- Your own filters. A feed can name chapter titles to cut wherever they turn up, like Intro or Trailer.
For a YouTube episode, which the direct download can import, Feedcast asks the SponsorBlock database first. Its timestamps are submitted and voted on by people who already watched the video, so they are exact to the second, and the video’s own chapters are only used when SponsorBlock has nothing.
Chapters and SponsorBlock are exact. The transcript is a judgement about spoken language, and host reads that blend into the conversation are the hardest case, which is why every cut is shown to you rather than applied silently.
Choosing what counts as an ad
In podcast episodes, what comes out is the sponsor read itself. SponsorBlock labels more than that, so for YouTube episodes Feedcast keeps nine categories, each switched on or off on its own. Five are on when you install it:
- Sponsor and Unpaid/Self Promotion, the paid read and the plug for the host’s own thing.
- Interaction Reminder, the “like, subscribe and leave us a review”.
- Intermission/Intro, the theme music at the top.
- Endcards/Credits, the sign-off after the episode is over.
Four more wait until you ask for them: Hook/Greetings for the warm-up, and Preview/Recap, Tangents/Jokes and Non-Music Section for when you want only the substance.
Cutting the file
The breaks are removed and the rest is joined back together, so a 32 minute episode with 5 minutes of ads becomes a 27 minute episode. It is a real cut, not a skip instruction your player has to honour, which is why it survives the trip into Apple Podcasts, Overcast or anything else. In audio episodes each cut lands in the nearest pause, so it never clips a word, and you can mark it with a short fade or a sound of your choice, or leave it seamless.
Chapter marks are repaired in the same pass. A chapter that sat inside an ad is dropped, every chapter after a cut moves back by the length of what was taken out, and when a topic carries on after the break, the two halves become one chapter again. The show notes and the new episode notification then say what happened, for example: Feedcast removed 2 ads (3:03) at 1:50 and 24:10.
Your download is never lost. Feedcast keeps the original for as long as you keep the episode, while storing only what it cut out, so it takes almost no extra space. Switch a cut off in Review Ads and the episode is rebuilt from the original in about a second.
Doing it again, unattended
Sponsor removal is worth having once and worth nothing unless it keeps happening. Feedcast sits in the menu bar, checks your shows on a schedule, and runs the whole pipeline on each new episode as it lands: download, transcribe, find, cut, repair the chapters, publish to your feed. The notification arrives once the clean episode is ready in your podcast app. Most weeks you never open Feedcast.
For YouTube sources there is a second pass. Segments are often submitted to SponsorBlock in the hours after a video goes up, so Feedcast keeps checking a recent episode for a while and cleans it again if better data arrives.
More than removed ads
The same pass shortens long pauses, evens out the volume, gives the episode chapters it never had and a transcript you can search. Read about transcripts and chapters, or see how the cleaned episode reaches your phone through a private podcast feed. Still deciding? Compare every way to skip podcast ads.