Add support for RSS feeds (fix dynamic audio files)

[kreativK]

This would make it possible to support services outside of Spotify like Apple Podcasts and Pocket Casts.

[kreativK]

Currently I see two ways of doing this:

1. Create specific fixes for all different podcast providers (at least the biggest ones) to trick them into serving all users the same audio.

2. Get two versions of the same episode with different dynamic ads and then use some sort of audio fingerprinting and compare them to distinguish the dynamic parts from the normal ones. Just not sure how feasible it would be. I guess it would take a lot of time if you had to wait for the extension to process the whole episode every time before it can start. Maybe you could start with like the first 10 minutes to make the episode playable faster and to remove dynamic ads in the beginning of the episode and then continue processing the rest in the background. I'm thinking it could continue processing the episode in chunks of 10 minutes to be able to add information as it's processed instead of having to wait for the whole episode to be processed. Segments from the server are only loaded in when the part of the episode it's located in is done processing and it's impossible create or submit segments until everything is finished. Parts that are detected as dynamic are marked with a local segment type that can be automatically skipped and they're used to position and create segments correctly.

The first alternative isn't very stable or optimal, right now I'm trying to go for the second alternative.

[slcn-dxd]

I investigated a similar problem and found that several German podcast providers make this relatively easy to handle. In their RSS feeds, they include MP3 URLs with an additional query parameter—typically a timestamp or unique identifier. For example:
https://traffic.megaphone.fm/EARLYSTUDIOSGMBH7215871780.mp3?updated=1767833249.

I discovered that downloading the same MP3 without this parameter consistently returns a version of the episode without any dynamically inserted ads. I observed this behavior with the providers megaphone.fm and julephosting.de.

It might be worthwhile to compile a list of podcast providers that use dynamic ad insertion and evaluate whether this behavior is common practice or merely an exception.

[kreativK]

From what I have seen, this is not common practice. The providers I have encountered uses unique signed url:s and there is (as far as I know) no way to obtain the original episodes this way.

This could still be useful for alternative 1, getting a list of podcast providers whose dynamic ads can be bypassed in one way or another to at least have some kind of support for RSS-feeds. I have completely abandoned alternative 2, it will most likely not work.

How did you download the mp3 without dynamic ads?

[slcn-dxd]

I just omitted the URL params in the download link which returned the episode without any ads.

For your second approach, would it be possible to obtain two versions of the same episode, generate an audio fingerprint in order to find all parts that are identical in both versions to find the time positions of the ads?

[kreativK]

I tried with your example but it didn't work, it just redirects to an episode with dynamic ads.

It's probably technically possible. For it to be feasible though you would have to fetch the mp3's with a range to not have to wait for the whole episodes to be fully fetched which could take minutes. But as far as I know you can't because, as previously mentioned, dynamic url:s can be signed and therefore can't be changed.

[kreativK]

Maybe something similar could be used as this.