For something that looks roughly the same wherever it’s played, video sure comes in a lot of formats. Online videos, including YouTube’s, are often Flash (FLV or F4V) files, while DVDs contain the Video_TS structure, TiVo shows get wrapped in their own proprietary MPEG-2 format, your camcorder captures clips in AVCHD–and the list keeps going. You shouldn’t need to know any of this to play and watch video, which is where Popcorn steps in. Roxio’s software imports these and other formats and compresses them for use on an AppleTV, iPhone, PS3, YouTube, DVD, and more. While it occasionally stumbles, the app comes in handy more often than it disappoints.

Popcorn imports video, processes it, and exports it using an easy-to-grok routine. Start by dragging in source files, such as downloaded QuickTime clips, home movies from a camera, or even a homemade DVD that lacks copy protection. You’ll be able to make simple edits to the video as needed, then pick from a dozen customizable output formats.

Useful presets for almost every major hardware device–and certainly all of Apple’s toys–made us feel like we could avoid the arcane world of manual video compression, which can bury you in resolution, frame rates, bit rates, codecs, and more. But advanced users can choose to modify everything further, plunging into those details for more precise control of Popcorn’s output.

Popcorn 4 tastes better when you compile Auto-Tune the News videos from YouTube.

You’re most likely to export everything to a DVD or iTunes, and Popcorn handles either task well. It’ll recompress a dual-layer DVD video into a smaller, single-layer disc or compile your footage into a movie DVD. Popcorn also includes thoughtful features that let you preview how everything will look before you commit, and you can export on a schedule when your Mac is unused. We really appreciate the ability to queue up several videos at once and let those jobs run while our machine is unattended.

Popcorn can even import Flash video from a web browser, and we captured clips from YouTube and other video sites online. But Hulu, Crackle, and other commercial video sites never worked right, and we couldn’t get Popcorn to recognize most commercial TV and movies on YouTube (Auto-Tune the News worked fine, for example, but MacGyver didn’t). Online-show capture could have been a killer feature, but instead DRM (digital rights management) copy-protection schemes keep some of these kernels from cooking.

As far as movies go, Popcorn can read from unprotected DVDs, such as discs you make in iDVD. But nearly every store-bought disc comes wrapped in DRM. It’s up to you to find software to first unlock the movies you purchase, and that often means frequenting the shadier parts of the Internet. The hits keep coming: If you bought a movie from iTunes, DRM prevents Popcorn from reading it, and online DRM frequently blocks shows from streaming websites–which, in a word, sucks.

On the home front, Popcorn can transfer and process video to and from a networked TiVo Series 2 or later, but similar DRM rules kept us from using our shows how we wanted. Even if you have HD TiVo recordings, Popcorn only exports at a 480×360 resolution in order to keep the TiVo and network gods satisfied. Some content providers won’t let you transfer shows at all, including HBO. And yes, we’re aware that the software doesn’t cause these problems directly. But whether you put the blame on Apple, HBO, TiVo, Roxio, or elsewhere, these limitations prevent Popcorn from realizing its full potential.