For PC television fans, up until now the only viable choice for TV viewing on the computer has been with an addon PCI or AGP (in the case of the All-In-Wonders) card. There have been USB breakout devices, but they have not been the perfect solution at the time. The slower USB 1.1 interface was one factor in the poor performance, and these breakout boxes often lacked some of the more advanced features found in dedicated TV cards.

While enthusiasts interested in adding TV features to their PC have many options, notebook users are a little more limited in their choices. There are also a number of people who feel uncomfortable opening up their store bought PC, and the last thing they want to do is open a PC up and installing a PCI card. ATI has taken another crack at the USB tuner in the form of the . Along with improving the visual quality of television viewing from their last product, the new tuner rides the much quicker USB 2.0 bus.

Features

Schedule and record TV programs at any time.
Capture video in MPEG 1/2 and 4 format
Capture still images
Zoom-in, pan or freeze live TV action with TV-ON-DEMAND"

The ATI TV Wonder USB 2.0

We picked up the ATI TV Wonder USB 2.0 during a recent visit to Toronto, and received what should be a final retail sample, so the ones you'll see in stores as of today should be the same as what we're going to be looking at.

The TV Wonder USB 2.0 is entirely encased in plastic, and has a good solid feel to it. Right next to the logo is the LED that indicates whether or not the device is on. I would have liked to have seen a more attractive colour, but it's what's inside that counts.

In order to begin using the device, you'll need to plug in a coax connection into the TV Wonder. For cable or antenna users, simply plug it in and allow the software to autoscan for channels. For satellite subscribers, you'll still need your receiver to decrypt the signals, as the TV Wonder does not do this.

As multimedia enthusiasts can tell you, a coax connection is not the best choice for image quality, to put it mildly. To put it bluntly, it's terrible. A better option would be to use a composite cable to connect your receiver or cable box to the TV Wonder. Another option is S-Video, which has better image quality compared to composite. The best solution is component video (aka RCA) which separates the video across red, green and blue. Mostly used in high definition setups, the TV Wonder USB 2.0 does not support component video, but does have connections for composite and S-Video, as well as left and right audio inputs.

Ultimately, the TV Wonder USB 2.0 is only part of the equation. The quality of the cables used will greatly influence the overall quality, as well as the TV you're using to watch it. If you're wondering why those $200 video cables look no better than a $10 S-Video cable, perhaps it's time to change that 13" TV.

The last couple connections are the power and USB 2.0. We'll go into more detail later on, but what you need to know is that all of the video processing occurs on the ATI Theater 200, so all the TV Wonder is left to do after is to stream the info to the hard drive for recording or directly to the MMC for viewing. At 480Mbps, this should be plenty of bandwidth for the TV Wonder's purposes.

The TV Wonder USB 2.0 is not bus powered, and requires an external power source to operate.

Depending on the power bar, the TV Wonder's power brick can take up to two spaces on the power bar. This is one of the issues we have with the device as it is bulkier than it needs to be. Other than the 6V power supply, the USB 2.0 cable is also included.

Theater 200

ATI's Theater 200 is ATI's flagship Video Processing Engine (VPE), and is the video decoder used in the TV Wonder USB 2.0. While earlier VPEs used a 9-bit analog-to-digital converters (ADC), the Theater 200 uses dual 12-bit ADCs. At 12-bits, some of the noise associated when converting an analog stream will be cleaned up when compared to earlier chips.

In respect to image quality, the Theater 200 offers a 2D-3 line comb filter. For composite video signals, the picture is improved because they are more accurately processed. Previously, only 2 lines were used for NTSC. How this works is the filter separates the color information and brightness information of the signal. These signals are also what is referred to as Y/C signal or luminance and chrominance. The Y/C signal is passed into the video scaler which adjusts the size or zoom rate of the video to be displayed on the screen. After the video is scaled it is changed into a digital format recognized by the video card and then it is displayed on your monitor. Without the video scaler and the comb filter, the image quality can be severely degraded, and you'll notice artifacts or "blockiness" in your video.

USB 2.0

USB 2.0 is a major step forward in terms of speed when compared to USB 1.1. This is an important upgrade to the TV Wonder USB line as video is bandwidth hungry. To put it in perspective, digitally uncompressed television signals have a bandwidth of 37Mbs. In order for previous USB tuners to function efficiently, these signals needed to be re-scaled or recompressed in order to effectively transmit the signals to the USB interface.

For example, re-scaling a signals to 640x480 looks fine at that resolution, but the problem is when playing the video at a higher resolution, there is video data missing and the end result is a poor image.

On the above left, the WinTV is sending a 320x240 image to the PC, while on the right is ATI's image quality. Given that USB 2.0 has 480Mbps of bandwidth, the TV Wonder USB 2.0 is not limited to re-scaling an image to meet the bandwidth demands of digital video.

Compression is another method to address the limitations of USB 1.1. By compressing an image, this method allows an external TV tuner to work around the USB 1.1 limitations. However, most of today's PC video compression parts still need work, and the image quality can be shaky between products. The TV Wonder USB 2.0 does not rely on compression, and sends the full sized video from the tuner to the PC.