The Matrox MXO addresses many tasks Mac editors working in DV, HDV, and DVCPRO HD (VariCam) need to accomplish. The key challenge facing those of us working with these formats isn't getting the material into our NLEs, because every major NLE supports FireWire ingest. The challenge has been getting the video out in a format our clients want.

Click To Enlarge The MXO has a small footprint and no fan, so it fits comfortably on most any desktop. Matrox supplies all the necessary cables, but the runs are short. You'll need to fashion your own harness if you want the MXO in a rack or the machine room.

DV, HDV, and DVCPRO HD are great acquisition formats, but few clients want masters delivered to them in those formats. For many of us, it's still Digital Betacam for standard definition and HDCAM or D5 HD for high-definition deliverables.

The MXO takes the DVI output of a PowerBook, G5, MacBook Pro, or Mac Pro and converts it to 601 video via SDI, component analog, S-Video or composite SD, or HD SDI. When used in conjunction with Final Cut Pro, that output can be frame-accurately output to videotape. Other QuickTime-aware applications such as Adobe After Effects can also access the MXO.

First impressions

Out of the box, the MXO looks like myriad other cheese-grater-styled pieces of gear inspired by the Macintosh G5/Mac Pro aesthetic. The blue LED positioned behind the grill indicator is another tip of the hat to twenty-first century industrial design. It's a compact box, less than 2 inches high and a few inches square, that sits comfortably between the Mac and its display. The DVI output of the Mac is fed to the DVI input of the MXO, which passes the signal through to feed the Mac's second monitor.

Communication between the Mac and the MXO is handled via USB. All the cables required between the Mac and the MXO are included in a single harness. On the back of the MXO are five BNC connectorsNfour for output (SDI and Y, Pb, Pr) and an input for external genlock. Composite and S-Video output share the Y, Pb, Pr jacks. The analog video output preferences are set through an MXO control panel available in the Mac OS X System Preferences pane. The MXO embeds as many as eight channels of audio in the SDI outputs. It also features a pair of RCA audio outputs for analog audio. I'd prefer XLR outputs, but I understand the logic behind Matrox's decision to go RCA. It keeps the MXO's footprint to a minimum, and most professionals opt for SDI-embedded audio for mastering.

Installing the MXO software took less than a minuteNa relief to those who have become accustomed to the interminable installs that plague much modern software. The installer loads several Easy Setups for Final Cut Pro and an intuitive control panel available through the Mac OS X System Preferences pane.

Using the MXO

Getting the MXO to feed my studio monitors was as easy as connecting the cables and selecting the proper pulldown menu in Final Cut Pro. Since the MXO can be bypassed via software, there's no need to disconnect it when it's not needed.

Throughout the editing process, the MXO proved itself a useful, high-quality, HD to SD down-converter. To set it up for down-conversion, choose one of three aspect ratio options for SD display (letterbox, anamorphic, or center cut) and a video signal format (composite, S-Video, or component).

Without a doubt, my favorite feature of the MXO is its ability to output full-screen, center-cut, standard-definition images in real time to an NTSC monitor while editing in HD. My standard setup in Final Cut Pro uses a 23-inch display for full-screen HD. Adding the MXO allowed me to see what my sequence would look like in full-screen 4:3 while cutting, and I found it more useful than I anticipated when working with 16:9 material.

Most of the HD material I work with is shot 4:3 protected. I prefer letterboxing to eliminate the need to protect for 4:3, but I don't write the checks. Most clients still prefer a full-screen 4:3 image, so 4:3 center cut it is. Over the course of long shooting days, a few shots, especially when shooting for documentaries and magazine formats, end up outside of 4:3 safety. Having a 4:3 monitor running in sync with the HD display throughout the offline editing process eliminated framing surprises in the final output.

Minding manners, keeping cool

The MXO is a well-behaved peripheral. When the Mac goes to sleep, it goes to sleep. When the Mac wakes, it wakes. Matrox advises users to monitor the MXO's temperature periodically. The device will automatically shut down when it exceeds the recommended operating temperature of 158 degrees Fahrenheit. When I kept the front of the MXO unobstructed, the operating temperature never crept above 130 degrees.

Outputting to tape with the MXO was straightforward. For RS-422 deck control, you'll need either a KeySpan USA-28X USB Twin Serial adapter or an Addenda RS-USB/4 Rosetta Stone adapter. I tested with the KeySpan model attached to a MacBook Pro. It performed steadily and allowed frame accurate inserts with Final Cut Pro's Edit to Tape feature to Sony Betacam and DVCAM decks through their analog and SDI video inputs.

The MXO features external genlock capabilities and also allows automatic black level adjustments when outputting in NTSC, so an editor can work with blacks at 0 IRE throughout the post process and have the MXO adjust to 7.5 IRE if necessary on output.

The MXO outputs NTSC 29.97 fps interlaced, PAL 25 fps interlaced, 1080i at 29.97 or 25 fps, or 1280 x 720p at 59.94 fps. 1080p output is not supported in this release.

A note on color space

Initially the MXO's reliance on the DVI output to generate YUV output gave me pause. I assumed that the DVI signal would have to be converted from RGB to YUV by the MXO for output. Since the signal already had been converted by the Mac's graphics card from YUV to RGB, this could theoretically lead to significant color shifts. Dedicated video capture and output cards such as the Decklink and Kona cards don't contend with that issue as they work exclusively in the YUV space.

Matrox engineers have skillfully avoided color space conversions by tapping into the Mac's graphics card before the YUV signal is converted to RGB, so the MXO performs similarly to a dedicated video card. It should be noted that the first few MXOs shipped could show a significant color space shift when attached to a Mac equipped with an ATI graphics card. Those MXOs did not access the YUV data correctly, forcing an RGB to YUV conversion of the DVI output. Matrox has since released a firmware update that fixes this problem. Current owners of early MXOs are advised to download the latest firmware update from the Matrox support site: www.matrox.com/video/support/.

Additional capabilities

The MXO can be used in presentation mode to display the output of the secondary monitor to an NTSC or HD monitor. This can be useful for PowerPoint and Keynote presentations. It's also handy for recording the output of the Mac desktop to videotape. When used for that purpose, the MXO can also feed the Mac's audio output to the recording device via stereo RCA (unbalanced) outputs.

Click To Enlarge The MXO allows the editor to switch among viewing modes instantaneously. Scrubbing/pausing delay settings minimize interlace flicker when paused. Other tabs include settings for external genlock, for temperature monitoring, and for using the MXO to output the Mac desktop in NTSC, PAL, 1280 at 720p (59.94 fps), or 1920 at 1080i.

The audio output of the MacBook Pro was unusable in the previously described config-uration due to the internal grounding configuration of the MacBook Pro, which is a documented Apple issue. Matrox is aware of the situation and will provide an outboard filter that corrects this issue, at no charge, to customers who need a solution. This issue has no effect on the audio embedded in the SDI signal when using the MXO for mastering to tape, so the vast majority of MXO users will never encounter the problem.

It was impossible to get the MXO to work as a preview device with After Effects 7 on my MacBook Pro running Mac OS X 10.4.7. Although I could select the MXO as a preview device within After Effects, the app-lication would never engage it for previews. This is because After Effects runs in Rosetta. The MXO drivers don't run in Rosetta. After Effects previews through the MXO will not be possible on Intel-based Macs until Matrox releases updated drivers that work in Rosetta, or until Adobe releases a Universal version of After Effects.

Conclusions

Overall my experience with the MXO was extremely positive. Real-time down-conversion of HD sequences from my notebook Mac while editing came in handy at client screenings. The MXO's portability allowed me to set up a mobile HD editing system quite easily. In the studio it was easy to forget about the MXO. I plugged it in, installed the software, and five minutes later I was editing. It was completely transparent during editing and made easy work of making high SD versions of my HD sequences. But for the Rosetta issues with After Effects and the annoying audio monitoring flaw when used in presentation mode, the MXO would have garnered an Award of Excellence. It's that good.