When Apple Computer Inc. introduced the iPod four years ago today, users and critics noticed something odd about the device: As an MP3 player, the iPod looked a tad over-equipped.

Why did Apple bother to put in a high-resolution display if that screen would show only song titles? Why include a complex operating system just to cue up MP3s? For that matter, why give an ostensibly music-only device a name as vaguely omnipotent-sounding as "iPod"?

Those were the right questions to ask. Since its introduction, the iPod has acquired a range of capabilities beyond music playback. It can store your address book, track your appointments, carry text notes, display your photo albums and slideshows, and collect podcast audio downloads -- and now it can play video, too.

Apple's latest iPod variation, announced Oct. 12, adds a bigger screen to play digital clips purchased off the company's iTunes Music Store, downloaded from the Web or converted from your own video collection.

But unlike other attempts at putting digital video in a pocket-size device, this iPod remains a music-first device, one that's actually smaller than its predecessor. A $299, 30-gigabyte model (27.8 GB actual capacity) is just under 1/2 inch thick; a $399 60-gig model (55.6 GB actual capacity) is slightly thicker.

Its color screen spans a mere 21/2 inches from corner to corner, but from a typical corneas-to-pixels distance of about a foot, it's surprisingly viewable. Although it's smaller than the screens on bulkier competitors such as Creative's and Samsung's Portable Media Centers and Sony's PlayStation Portable, the iPod's screen is also bigger than the screens on some handheld TVs and most video-capable cell phones.

For occasional viewing in trains, planes, buses and waiting rooms, that seems good enough. The rest of the time, this iPod is the same as it ever was: a simple and elegant machine to play music (both purchases from Apple's iTunes store and songs copied from CDs, but not downloads from most other online stores) and store other data, from photos to your phone book.

This iteration of the iPod does surrender some battery life for its newfound video capability. The 30-gigabyte model could sustain only about two hours and 15 minutes of video playback and 13 hours of music listening. A 60-gig version, meanwhile, allowed just over four hours of video watching; Apple estimates its music-only battery life as 20 hours.

The battery is locked inside the iPod's case; when it wears out, which should take a few years of sustained use, you'll need to pay Apple or another firm for battery-replacement service instead of just popping in a new one yourself. A lesser subject of some complaints, the lack of a "gapless playback" option to eliminate distracting pauses between tracks in opera and classical performances, lives on as well.

The new model also shares quirks with its smaller sibling, the iPod Nano. Because it doesn't ship with a power adapter, it can be recharged only by plugging it into a computer with the included USB cable, a process that took about three hours. It doesn't allow file transfers via FireWire, which limits owners of older Macs and PCs to unbearably slow synchronization sessions over their machines' low-speed USB 1.1 ports. And without the remote-control jack of older iPods, many accessories can't plug into this new model.

But while the iPod's hardware makes watching videos on the go a realistic option, the iTunes software and store needed to get that content into an iPod don't always make it cost-effective or convenient.

The video downloads for sale consist of music videos, six short movies from Pixar Animation Studios, and episodes of five TV shows from ABC and the Disney Channel. Each sells for $1.99 and can be played on up to five computers at once and an unlimited number of iPods -- but can't be streamed over a home network or copied to DVD for viewing on a TV. (You can't even copy a music video's soundtrack to an audio CD.)

These downloads appear terrific on an iPod's screen, but on a computer monitor, the limits of their 320-by-240-pixel resolution become embarrassingly obvious.

The TV shows are the most interesting part of the equation. The programs ("Lost," "Desperate Housewives," "Night Stalker," "The Suite Life of Zack and Cody" and "That's So Raven") appear the day after they air, commercial-free. This is the first time major network shows have been made available as paid downloads -- which should be a subject of lasting shame for the network executives who took so long to discover that you can, like, sell things online.

It would be financially foolish to watch every episode of a show on iTunes, but this offers an easy way to catch up on ones you missed -- that is, given sufficient time and bandwidth: One episode of "Lost" took about 25 minutes to download over a DSL connection.

Even then, you should consider the premium you pay for convenience. Where iTunes music downloads sound almost as good as a CD, iTunes videos look dramatically worse than a DVD. And they don't offer the escape from Apple's copying restrictions available to music buyers, who can burn their downloads to audio CD, then copy them to their computers in a format of their choice.

These limits may be fine for the free video podcasts offered through iTunes, but they're much less palatable in something marketed and sold as your lasting property.

Getting other video files on an iPod, whether downloaded off other sites or made in such programs as Apple's iMovie, is unacceptably complicated. Instead of simply dragging a clip into iTunes to have it converted and copied automatically, you must adjust esoteric file-export settings in iMovie, buy a copy of Apple's $30 QuickTime Pro, or mix and match random freeware programs to make your video clip iPod-ready.

This level of complexity is standard procedure in much of computing, but it's not what Apple sells. That, and the selection of video downloads sold at iTunes, needs to improve in a hurry, or the "video" iPod will remain just a great way to listen to music on the go -- not that Apple would necessarily be upset with such an outcome.

Living with technology, or trying to? E-mail Rob Pegoraro at rob@twp.com. To watch a video podcast about this new iPod, visit www.washingtonpost.com/podcasts.

Apple offers music videos, animated shorts and five TV shows to download for its new iPod.