For this feature we're looking at the Xbox 360 as an HD DVD player, not as a gaming machine.

Microsoft's $400 Xbox 360 game console comes with a built-in DVD drive. For an additional $200, Microsoft offers the external HD DVD Player to hook up to the console. This $600 combination is a bargain-priced starting point for Xbox 360 owners who want to begin watching high-def movies; however, the combo has some significant drawbacks.

The HD DVD Player is easy enough to set up: You connect it to the Xbox via a USB 2.0 cable, and then install the included Xbox drivers. At the back of the Xbox unit, you'll find two USB ports, for attaching additional Xbox peripherals such as the Wi-Fi adapter or the Xbox Live Vision Camera. The Xbox's on-screen display for viewing disc playback information looks elegant; and the unit's response time when navigating a disc was better than that of the stand-alone players.

Using the two-device combo is a kludgy way to play movies, though. The elongated, Windows Media Center-like remote that comes with the HD DVD Player has an eject button, which controls the Xbox's DVD drive tray, but not the HD DVD Player's tray. To open the HD DVD Player itself, you must manually press the button on its front.

Video output quality is another big flaw that detracts from the device's merit as a home theater player. All of the stand-alone high-definition video players we've tested can attach to your television and amplifier via an HDMI connection, which lets you watch hi-def movies at their fullest quality. The Xbox doesn't offer anything better than analog component video, which produces a decent, but not stellar high-definition image.

In our tests, this omission of HDMI impacted image quality, as seen on the 50-inch Pioneer Elite PRO-FHD1 televisions we used for testing. High-definition and standard-definition images on the Xbox showed a softness and lack of depth and detail when compared to images the other players output via HDMI.

Viewed over component video -- a $40 extra-cost option for the Xbox 360 core system, but included with the hard drive-enabled model I tested -- the Xbox's HD DVD output is limited to 1080i (it can display 1080p, but only via a VGA connection). Occasionally, the Xbox's output would slap us in the face with an ugly interlacing artifact. A brick wall in chapter 7 of Mission: Impossible 3, for example, looked especially annoying, vibrating in a way that brick walls most certainly shouldn't.

Video output was badly overscanned, meaning that movies were slightly cut off at the sides of the screen. And when I popped in a wide-screen standard-definition DVD, the image looked squeezed

The Xbox is also lacking in its audio support. Microsoft says the player can decode a variety of audio formats - -Linear PCM, Dolby TrueHD, DTS-HD Master Audio, DTS-HD High Resolution, DTS Digital Surround, Dolby Digital 5.1, Dolby Digital Plus--and it outputs audio only as Dolby Digital or PCM.

Based on our tests, if you don't already own an Xbox, you have no earthly reason to buy these two boxes just for next-generation video playback. A standalone HD DVD player (such as the inexpensive $500 Toshiba HD-A2 ) will give you better picture and sound, without the hassle of running two gadgets to do the job of one.