You can use git-annex as a podcatcher, to download podcast contents. No additional software is required, but your git-annex must be built with the Feeds feature (run git annex version to check).

All you need to do is put something like this in a cron job:

cd somerepo && git annex importfeed http://url/to/podcast http://other/podcast/url

This downloads the urls, and parses them as RSS, Atom, or RDF feeds. All enclosures are downloaded and added to the repository, the same as if you had manually run git annex addurl on each of them.

git-annex will avoid downloading a file from a feed if its url has already been stored in the repository before. So once a file is downloaded, you can move it around, delete it, git annex drop its content, etc, and it will not be downloaded again by repeated runs of git annex importfeed. Just how a podcatcher should behave. (git-annex versions since 2015 also tracks the podcast guid values, as metadata, to help avoid duplication if the media file url changes; use git annex metadata ... to inspect.)

templates

To control the filenames used for items downloaded from a feed, there's a --template option. The default is --template='${feedtitle}/${itemtitle}${extension}'

Other available template variables:
feedauthor, itemauthor, itemsummary, itemdescription, itemrights, itemid, itempubdate, author, title.

catching up

To catch up on a feed without downloading its contents, use git annex importfeed --relaxed, and delete the symlinks it creates. Next time you run git annex addurl it will only fetch any new items.

fast mode

To add a feed without downloading its contents right now, use git annex importfeed --fast. Then you can use git annex get as usual to download the content of an item.

storing the podcast list in git

You can check the list of podcast urls into git right next to the files it downloads. Just make a file named feeds and add one podcast url per line.

Then you can run git-annex on all the feeds:

xargs git-annex importfeed < feeds

recreating lost episodes

If for some reason git-annex refuses to download files you are certain are in the podcast, it is quite possible it is because they have already been downloaded. In any case, you can use --force to redownload them:

git-annex importfeed --force http://example.com/feed

distributed podcatching

A nice benefit of using git-annex as a podcatcher is that you can run git annex importfeed on the same url in different clones of a repository, and git annex sync will sync it all up.

centralized podcatching

You can also have a designated machine which always fetches all podcstas to local disk and stores them. That way, you can archive podcasts with time-delayed deletion of upstream content. You can also work around slow downloads upstream by podcatching to a server with ample bandwidth or work around a slow local Internet connection by podcatching to your home server and transferring to your laptop on demand.

youtube channels

You can also use git annex importfeed on youtube channels. It will use youtube-dl to automatically download the videos.

To download a youtube channel, you need to find the feed associated with that channel, and pass it to git annex importfeed. There does not seem to be an easy link anywhere to get the feed, but you can construct its url manually. For a channel url like "https://www.youtube.com/channel/$foo", the feed is "https://www.youtube.com/feeds/videos.xml?channel_id=$foo"

metadata

As well as storing the urls for items imported from a feed, git-annex can store additional metadata, like the author, and itemdescription. This can then be looked up later, used in metadata driven views, etc.

To make all available metadata from the feed be stored: git config annex.genmetadata true