+### Upgrading within ikiwiki: from simple to fancy
+
+#### My test podcast
+
+For this test, I chose a podcast that tries to work around ikiwiki's
+current limitations by issuing two separate `inline`s:
+
+* One with `feedonly=yes` that includes `.mdwn`, `.pdf`, and `.mp3`
+* One with `feeds=no` that includes only `.mdwn` (and makes a trail)
+
+This has the following effects:
+
+* Browser: sees just the articles (each of which has a manually
+ created link to its corresponding media file)
+* Feedreader: sees all the articles and media in one flat stream
+* Podcatcher: sees just the media (sans articles)
+
+I want instead to write one `inline` with these effects:
+
+* Browser: sees just the articles (each of which automatically links
+ to its enclosure)
+* Feedreader: sees just the articles (each of which specifies its
+ enclosure)
+* Podcatcher: sees just the enclosures (each of which has an enclosing
+ article, rendered as the media's "description")
+
+#### Upgrade steps
+
+7. Set up a non-production copy of the podcast.
+ 7. Visually diff RSS and Atom feeds against production.
+ 7. Subscribe to the copy (both feeds) in `r2e`, iTunes, Downcast.
+7. Apply fancypodcast patch to the installed ikiwiki:
+ 7. `cd ~/Documents/trees/ikiwiki && git checkout fancypodcast`
+ 7. `git diff --no-prefix master > ~/Documents/trees/localpatches/www/ikiwiki/fancypodcast.diff`
+ 7. `cd ~/Documents/trees/pkgsrc-current/www/ikiwiki && make deinstall && make install clean`
+7. Verify that simple podcasts are unaffected:
+ 7. Rerun `ikiwiki --setup`.
+ 7. `diff -uB simple-before.rss simple-after.rss`
+ * A few new elements and attributes, as expected.
+ 7. `diff -uB simple-before.atom simple-after.atom`
+ * No change.
+7. Remove the feed-only `inline` and enable feeds on the remaining one.
+7. Convert articles' manual download links to `\[[!meta enclosure=""]]`.
+7. I want existing and future podcatchers to get my new fancy
+ episodes, and I know my podcast isn't in any planets, so I'm
+ going to skip [[tips/howto avoid flooding aggregators]].
+7. Rerun `ikiwiki --setup`.
+7. Verify browser shows the same stuff.
+7. `diff -uB simple-after.rss fancy-after.rss # and atom`
+ * MP3s and PDFs are no longer naked enclosures, but belong to
+ articles as they should.
+ * Articles have updated modification times, as they should.
+7. `r2e run` (both RSS and Atom)
+ * Nothing new with the default `trust-guid = True` (otherwise
+ would expect updated articles).
+7. iTunes "Update Podcast" (both RSS and Atom)
+ * Added one episode per article, with article text as the episode
+ description.
+ * Kept old naked-enclosure episodes around.
+7. Downcast refresh (RSS):
+ * Added one episode per article, with article text as the episode
+ description.
+ * Kept old naked-enclosure episodes around.
+7. Downcast refresh (Atom):
+ * Added one episode per article, with no episode description
+ (expected, see feature table).
+ * Kept old naked-enclosure episodes around.
+
+Different tradeoffs are possible. These seem okay to me.
+
+### Importing into ikiwiki: fancy (from another CMS)
+
+#### My test podcast
+
+For this test, I chose a podcast currently being published with
+Textpattern and tru_podcast, because I'd strongly prefer to publish
+it with ikiwiki instead.
+
+#### Upgrade steps
+
+7. Set up a non-production copy of the podcast.
+ 7. Visually diff RSS and Atom feeds against production.
+ 7. Subscribe to the copy (both feeds) in `r2e`, iTunes, Downcast.
+7. With a fancypodcast-enabled ikiwiki installed:
+ 7. Copy content from Textpattern to ikiwiki:
+ 7. Match article paths to preserve `/YYYY/MM/DD/post-title` permalinks.
+ 7. Match enclosure paths (or redirect) to preserve Textpattern's URLs.
+ 7. Match titles, post dates, and guids with `\[[!meta]]`.
+ 7. Match feed paths with permanent redirects from `/atom/` to
+ `/index.atom` (and same for RSS).
+ 7. `\[[!inline]]` the articles.
+ 7. Rerun `ikiwiki --setup`.
+7. Stop Textpattern, start ikiwiki.
+7. Verify that podcatchers see the feeds and don't redownload anything.
+7. Naively add two new blog posts, one with an enclosure.
+7. Verify that podcatchers download the new enclosures.
+
+-----
+
+## Future improvements
+
+### iTunes fancy podcasting
+
+* [iTunes-specific tags](https://www.apple.com/itunes/podcasts/specs.html)
+ appear to be RSS-only
+ * If they work in Atom, teach `inline` to optionally iTunesify RSS/Atom.
+ * Else, add `itunes` as a third kind of feed (RSS plus more stuff).
+* Notable tags for feeds:
+ * `itunes:subtitle`
+ * `itunes:author`
+ * `itunes:summary` (same as `description`)
+ * `itunes:owner` (includes `itunes:name` and `itunes:email`)
+ * `itunes:image href=''`
+ * `itunes:publisher`
+ * `itunes:category text=''` (can contain subcategories)
+ * `itunes:keywords`
+* Notable tags for entries:
+ * `itunes:duration`
+ * [[!cpan Audio::TagLib]] might be fastest, if present and applicable
+ * [ffprobe](http://ffmpeg.org/ffprobe.html) is reasonably fast
+ * [mediainfo](http://mediainfo.sourceforge.net/) is way slower
+ * Cache computed durations as pagestate
+
+### Fancy podcast aggregating
+
+* Write tests comparing a fancy podcast (HTML and feeds) against
+ the same podcast aggregated and republished, then make them pass
+ via changes to `aggregatepost.impl` and [[plugins/aggregate]].
+
+### Other ideas
+
+* Don't render template text (e.g., "Use this template to insert a
+ note into a page") in feeds.
+* Optionally specify the enclosure's:
+ * MIME type, in case `File::MimeInfo` guesses wrong.
+ * Duration, in case `ffprobe` guesses wrong.
+* Optionally specify enclosures outside the wiki:
+ * Some people don't want to store big unchanging files in the VCS.
+ * Other people like [podcasting found media](http://huffduffer.com/about).
+ * We'd have to download the file just to compute some metadata
+ about it, and then somehow not frequently re-download it.
+* Configurably generate additional subscription links (such as
+ iTunes) alongside the RSS/Atom ones in [[plugins/inline]].