How does an iPhone know which mp3s are podcasts?

Question

I recently got an iPhone, and quickly found I would rather use the Zune software instead of iTunes. So I turned on the manual syncing, and I can just drag the mp3 files I want over to the iPhone in iTunes. The problem is that some podcast mp3s show up in the podcast section and some do not. It wouldn't really matter except that only podcasts save their play position.

So the question is: how does an iPhone know which mp3s are podcasts? I assume it's a certain field in the ID3 tag, but I don't know which.

Edit: I found a solution for me. I had iTunes watch my Zune podcast folder. So when I launch iTunes, it seems to figure out all those files are podcasts. I can drag them over to the iPhone and they work as intended.

Answer 1

This is now easily solvable in iTunes9. If you right click on a file and click 'Get Info' you can change the file to a podcast under the options tab.

Answer 2

I think that the way that iTunes separates out podcasts in the Library has to do with how podcasts are synced. Podcast are handled differently than Mp3s.

I just dug into the iTunes Music Library.xml and saw that on podcasts, the following elements appear under podcasts

<key>Podcast</key><true/>

So it has to to with the fact that iTunes flags podcasts as such, and know to handle them differently.

UPDATE: Also, its more than just that key-value pair on the podcast entry, because if you add that key-value pair to any song, it gets removed by iTunes when you close it

UPDATE 2: I also found the entry specifying the Podcast "playlist"

    <dict>
        <key>Name</key><string>Podcasts</string>
        <key>Playlist ID</key><integer>11896</integer>
        <key>Playlist Persistent ID</key><string>6D71FCACB79A978D</string>
        <key>Distinguished Kind</key><integer>10</integer>
        <key>Podcasts</key><true/>
        <key>All Items</key><true/>
        <key>Playlist Items</key>
        <array>
            <dict>
                <key>Track ID</key><integer>7194</integer>
            </dict>
            <dict>
                <key>Track ID</key><integer>7192</integer>
            </dict>
            <dict>
                <key>Track ID</key><integer>7190</integer>
            </dict>
        </array>
    </dict>

Long story short, iTunes is doing a lot of work in the background!!

Answer 3

There is a handy free Applescript from Doug's Scripts that will re-add the selected tracks as podcasts.

Re-Add Selected Tracks as Podcast v1.2

Answer 4

A quick look through my iTunes library shows that most Podcasts have the ID3 genre attribute set to... "Podcast"

Answer 5

You can also click the "remember playback position" check box for the appropriate tracks. See this article from LifeHacker.com

Answer 6

For MP3s at least, it isn't just one ID3 tag -- it's several -- but I have managed to convince iTunes that an MP3 is a podcast strictly by manipulating the ID3 tags. (I copied all the tags from an iTunes-downloaded podcast using MP3Tag, tweaked a couple of them to prevent the new file from colliding with the old one, and did a manual add-file-to-library in iTunes, after which the MP3 appeared in the podcast list alongside the original 'cast I pulled the tags from.)

Unfortunately I haven't had time to figure it out well enough to take arbitrary MP3s and tag them as podcasts from scratch. But it does seem to be possible, if far more arcane than it needs to be.