Podcast Producer (or, specifically, the “podcast capture” application) gives you a simple “good,” “better,” “best” set of options for selecting compression codecs.
If you’re on a machine with Apple Intermediate Codec installed (IE, any machine with iLife), the “best” preset will use AIC. That’s great in terms of CPU overhead, but not so great in terms of harddisk space.
Ideally, if you’re recording off a screen capture device, you want to record device native (say, 1024×768) with light H.264 compression. Luckily, there are a couple ways to modify the presets that podcast producer uses.
If you poke into the Podcast Capture plist:
/Library/Preferences/com.apple.PodcastProducerCompressionSettings.plist
you’ll find the settings living there. Three for screen, three for audio and three for video. Unfortunately, if you go changing that file willy-nilly, you’ll find your changes quickly reverted. The secret? Add:
<key>custom</key>
<true/>
your changes will stick.
That plist doens’t give you a ton of control over the size of the video. To adjust that, you can go one step up the chain and modify:
/System/Library/Frameworks/QTKit.framework/Versions/A/Resources/compressionPresets.plist
Within “PodcastProducerCompressionSettings.plist” you’ll see references to things like “QTCompressionOptionsPrivateH264Video” – that just points to entries within compressionPresets.plist.
You can look at the entries already in there to understand how the ‘sizeMode’ key relates to setting the width, etc. It may be possible to set that in the PodcastProducerCompressionSettings plist, but I haven’t had success.