Long ago, in a land far, far away…actually, just a few years ago, probably in your own home or office you could most likely find yourself sitting in front of a tiny 14" monitor which would pale in comparison to your smallest 20" TV. Unfortunately the prices of computer monitors, at least a few years ago, kept most 17" and larger displays out of the hands of the mainstream consumer, although most enthusiasts had dreams of the $600 17" wonders.

Times do change, and currently, owning a 17" monitor isn’t that big of a deal anymore. Monitor prices have dropped tremendously, and what used to cost anywhere between $600 and $900 can now be had for under $400. If quality isn’t your top concern, a 17" monitor can become your new best friend for a little over $200, while it may not be the best looking friend you’ve had it’ll get the job done.

However, during the time when 14" monitors were the most affordable monitors out there, a few companies decided to take advantage of something that has quietly become a household necessity these days, the television. Companies like ATI began offering TV output ports directly on their video cards, which meant that at a sacrifice in visual quality, you could make use of a much larger screen for your computer. Since those days, the quality of TV output on video cards has improved dramatically, however more importantly, the price of including such a feature with a card no longer drives the price of the card to unreasonable levels.

In the past, the only video cards that did feature TV output were ones most hardcore gamers or knowledgeable enthusiasts wouldn’t dream of touching. Virtually every video card produced after the 3dfx Banshee now has support for TV output, and at a quality that once was only available on dedicated $300+ TV output cards. But what’s the catch? You’ve been "in" the industry long enough to know that no dream technology comes without a catch, there’s a definite reason users haven’t dropped their 17" CRT monitors in favor of 20" TVs.

The Tradeoffs

The first thing you must keep in mind is that a computer monitor is capable of displaying much higher resolutions than your standard NTSC or PAL TV. The NTSC standard calls for 525 scan lines, however of those 525 scan lines only 483 are active. The European version of the US standard, is PAL, and calls for a higher resolution at a slightly lower refresh rate. What this basically turns out to be is that your standard TV set, whether it is a NTSC or PAL compliant set, can barely display the lowest resolution your desktop probably supports, 640 x 480.

The resolution difference between TVs and computer monitors is the source for quite a few limitations that are placed on TV output modes. It used to be the case that enabling TV output forced your desktop into a 640 x 480 resolution at a fixed refresh rate, usually around 60Hz or lower. This was the most straightforward way of accomplishing the goal of taking what you see on your desktop, and displaying it on a TV. This brings you to the first tradeoff you must make with enabling TV output, desktop resolution/refresh rate degradation. Most manufacturers have taken routes to make this tradeoff less noticeable, their methods of doing so can differ greatly, so this is one of the first things you’ll want to consider.

Unlike your desktop, a higher resolution (i.e. 800 x 600 vs 640 x 480) displayed on your TV won’t necessarily yield a more detailed picture. This is due entirely to the scan line (resolution) limitations of both the NTSC and PAL standards. Going for a TV output feature on a video card simply because it supports a higher resolution won’t give you a better viewing experience.

On the other hand, while 640 x 480 is fine for your desktop and even games (it doesn’t matter that much once you’re running on a 35" screen), playing back DVD movies using a software decoder sometimes may be hurt by a 640 x 480 resolution limitation. A perfect example of this would be Zoran’s SoftDVD, which retains a performance hit when playing back in 640 x 480 vs 800 x 600, at the same time, some software DVD decoders may experience problems during playback at any resolution under 800 x 600. Translation? If you’re planning to use your TV output for DVD playback on your TV, and you don’t have a hardware DVD decoder card, 800 x 600 TV out support is more of a desired option.

The manner in which a TV puts a picture on the screen is not all that dissimilar from how a monitor does the same, unfortunately there is a dividing line that provides manufacturers with another gap to bridge, flicker. In the earlier days of TV output, obtaining a flicker free picture was not the easiest thing to accomplish, since then manufacturers have included workarounds for maintaining a fairly flicker free image on your TV, however the quality of these methods varies as well, this is the second factor you’ll want to consider when exploring TV output solutions on various graphics cards.

The clarity of text on your TV screen from a TV output on a video card is generally far from legible relative to what you see on your monitor. There are some manufacturers that have attempted to rectify this situation by offering software tweaks that supposedly increase the "sharpness" of displayed text, however the final decision is for your eyes only, making this the third factor to consider.

Putting the cards to the test

Contrary to popular belief, there are only a few TV output chips that are widely used by graphics card manufacturers. The four main solutions being compared in this article are the Brooktree BT869, the Chrontel CH7002D-V, the Matrox MGA TVO, and the ATI ImpacTV2.

ATI ImpacTV2

This proprietary controller is used on the ATI Rage 128 and provides the same basic functionality that the Chrontel and Brooktree solutions offer.

Brooktree BT869

The Brooktree BT869 is a very popular TV output controller and is featured on all TNT/TNT2 cards that support TV out (except for the Canopus Spectra 2500 and ASUS TNT/TNT2 cards) as well as Savage4 cards with TV out support, and the Voodoo3 3000. The supported resolutions are 640 x 480, 800 x 600, and 1024 x 768.

The benefit of the higher resolutions is not necessarily for better TV display, rather for support for higher desktop resolutions while running with TV output enabled. The BT869 is capable of outputting both to your monitor and an external TV, however they both must be at the same resolution.

Chrontel CH7002D-V

This chip was primarily used by Canopus, and features the same functionality as the BT869.

Matrox MGA TVO

The MGA TVO is used on the Matrox G400 line of video cards and supports resolutions up to 1024 x 768. What makes the TVO unique is that it is the driving force behind Matrox?s DualHead (see AnandTech?s review of the Matrox Millennium G400) technology, and essentially treats the TV output as a second monitor. This allows your desktop resolution/refresh rate to remain independent of your outputted TV resolution/refresh rate.

The Test

The four cards were tested at all supported resolutions, using three different tests, however due to the relative similarities between all tested resolutions and download constraints, only 800 x 600 (when possible otherwise 640 x 480) was used for the screen captures.

The first test is a screen capture from Rage Software?s Expendable. The original capture was performed at 1024 x 768 x 32-bit color, and demonstrates gaming image quality and resolution limitations.

The second test is Microsoft Wordpad displaying script.doc, a document file included with every Windows 9x installation. The capture was performed at all supported resolutions.

The third test is a DVD playback test using Zoran?s SoftDVD and a Phillips DVD drive displaying two scenes in the movie Ronin. The two scenes are designed to illustrate any banding or other visual artifacts created by the TV output.

The video card?s output was first tested on a Sony television (NTSC) for visible signs of flicker, image quality loss, and other noticeable artifacts produced by the TV output controller. The screen captures were performed using a S-Video cable from the video card directly to the input port on a test bed equipped with a Matrox Marvel G200, this was done to eliminate the influence of the test TV as an image degrading factor.

Gaming Test: Expendable Capture

ATI ImpacTV2

Click to Download Original Capture (2.5MB BMP)

The ImpacTV2 is what you can consider the standard for TV output to be.  The image isn't as vibrant as it could be, however it is definitely more than what previous generations of TV output controllers were capable of producing.  Unfortunately, the drivers and technology require the desktop to be fixed at the same resolution and refresh rate as the output display, which unfortunately limits what you're capable of doing while using your TV as an output. 

Brooktree BT869

Click to Download Original Capture (2.5MB BMP)

The BT869 provided the most vibrant picture of the roundup, although with a bit of gamma tweaking the competition could be brought up to essentially the same level, the Brooktree solution seems to be ideal for gamers.  Most likely why it was used on the TNT2/Savage4, primarily gamer cards.   Unfortunately the picture does change (no pun intended) when you look at the Voodoo3's implementation of the BT869...

3dfx Voodoo3 3000 (Brooktree BT869)

Click to Download Original Capture (2.5MB BMP)

For one reason or another the Voodoo3's TV output, albeit the same BT869 used on the Creative Labs TNT2 Ultra tested above, was much worse in quality than any of the reviewed output devices. While the issues could be driver related, they are most likely due to 3dfx's implementation of the BT869 on the 3000 card itself. The same results were duplicated across three different Voodoo3 3000 boards AnandTech had in lab, all three of which were retail boxed boards.

Chrontel CH7002D-V

Click to Download Original Capture (2.5MB BMP)

The Chrontel solution won the praise of many reviewers during the days of the Canopus Pure3D-2, and rightfully so, it easily offers quality that is comparable if not superior to the Brooktree BT869. The Chrontel isn't widely used any longer, however for those of you with older Canopus boards, you're pretty much set with gaming quality.

Matrox MGA TVO

Click to Download Original Capture (2.5MB BMP)

The Matrox MGA TVO on the Millennium G400 provided an excellent picture, with barely any flickering, unfortunately the output was plagued by color banding.  The color banding issues were much more prominent with games than under any other applications, however the screen shots seem to exaggerate the effect as the banding was not as noticeable on the TV screen as the shots depict it to be.   Regardless, the color banding was the main problem in an otherwise excellent quality TV output by the TVO.

Text Legibility Test: Wordpad

ATI ImpacTV2

Click to Download Original Capture (2.5MB BMP)

The ImpacTV2 on the Rage 128 had horrible text output, and the drivers featured no controls to adjust the sharpness of the text (no enhancing utilities).  For presentations, the Rage 128's ImpacTV2 doesn't seem to be the best in the business by a long shot.  If all you're interested in is playing games on your TV, then it's not so bad, but typing isn't the most pleasant experience.  After around 30 minutes of staring at the screen you'll begin to wonder why you hadn't invested in another solution...

Brooktree BT869

Click to Download Original Capture (2.5MB BMP)

The Brooktree BT869 is definitely superior to the ImpacTV2 in terms of text output quality, however it is still quite blurry.  The outputted screen was fairly flicker free however the clarity of the text was not nearly as great as that of the Matrox MGA TVO.

3dfx Voodoo3 3000 (Brooktree BT869)

Click to Download Original Capture (2.5MB BMP)

Being limited to a 640 x 480 resolution, the Voodoo3's implementation of the BT869 looked very similar to the Creative's implementation from above, as the case should be.

Chrontel CH7002D-V

Click to Download Original Capture (2.5MB BMP)

The Chrontel output was superior to that of the ATI, however not by a great degree.  The text was clear and well defined, however it wasn't sharp, keep in mind that the final decision is up to your eyes so give it a look.

Matrox MGA TVO

Click to Download Original Capture (2.5MB BMP)

The color banding problems were not as big of a factor with the text output tests on the G400, however it is obvious (notice the horizontal lines) from the screen shot.  The text output of the G400 is superior to that of the competition, Matrox's handy "enhance text" setting does seem to greatly improve the overall quality of the text.  The text is much more well defined and easier to look at than on the other boards, the MGA TVO provides you with output from a world far from that of the ATI ImpacTV2.

DVD Playback Comparison

The DVD playback quality comparison was primarily done to show the advantage of Matrox's DVDMax feature over the competing forms of outputting DVD to a TV.  DVDMax essentially allows you to run a movie in a window on your main desktop at any resolution, and output that movie, in full screen, to your TV.  The quality is amazing and truly makes the G400 the best option for a user looking to use their computer for more than just playing games, whether or not Matrox will deliver the G400 in large enough quantities in a respectable time is another question.  The DualHead technology is definitely superior to most forms of TV output, unfortunately you're limited to the G400 if you want that feature which may be fine for some users, but unheard of for others. 

Matrox MGA TVO

Click to Download Original Capture (2.5MB BMP)

Here you can see some of the effects of that banding on the G400 in the explosion

Click to Download Original Capture (2.5MB BMP)

Brooktree BT869

Click to Download Original Capture (2.5MB BMP)

Click to Download Original Capture (2.5MB BMP)

Just some eye candy ;)

Click to Download Original Capture (2.5MB BMP)

As far as TV output goes, for games, the Brooktree BT869 just about covers your basic needs, however when it comes to presentations or text display you're much better off with the Matrox G400. The ATI Rage 128's ImpacTV2 does a fine job at games and doing the basic job of putting your desktop on your TV, unfortunately once you try and view some text on the screen you start to realize why the ImpacTV2 isn't used as a presentation aid too often. The old Chrontel chip can be used as little more than a reference guide for the rest of the controllers, however it is obviously a chip that was ahead of its time.

The Voodoo3's quality was on the disappointing side as well, which was interesting enough considering that the Voodoo3 used the same Brooktree chip that was present on the TNT2 and Savage4 boards AnandTech tried. The quality difference between TNT2 boards was negligible, as all of them used the same chip, however the difference between the Voodoo3 and all other implementations of the BT869 was definitely worth mentioning.

For DVD output, the Matrox G400 holds the quality trophy, although the color banding issues AnandTech experienced during the tests was a bit disappointing. If you're going to use your computer as a DVD player for your TV or home theater, keep one thing in mind, although the video may be there, 5.1 Dolby digital is still out of the reach of your run of the mill sound cards. There's just no replacing a true home theater system, although you can come pretty close...