It is nearly impossible to discuss video acceleration on the PC without mentioning ATI. As one of the first vendors to offer motion compensation, iDCT and alpha-subpicture blending in hardware, ATI has set the precedent in this realm, rivaled only by the now-defunct S3 add-in boards. To this day, Matrox and 3dfx have yet to include any form of hardware acceleration for MPEG-2 decoding!

"Performance features assist the CPU in the decoding process, leaving the CPU free to handle other applications. System requirements are also lowered, since powerful processors aren't needed for full-frame decoding. Motion compensation is the first of these features, decreasing CPU load by about 25%. Also integrated into the RADEON core is an iDCT engine, which complements the motion compensation unit. iDCT accounts for roughly 15% of the decoding process, so a machine boasting both of these features will enjoy roughly 40% less CPU utilization while engaged in video playback than a system lacking them. Some of the performance features may also bleed into the quality category. For instance, motion compensation uses a 9-bit error term that may be truncated to 8-bits by some engines, resulting in a loss of quality. ATI's motion compensation engine uses the full 9-bits to maintain video integrity and thus does not suffer the loss. In addition, the RADEON also supports alpha subpicture blending. This is another quality-targeted feature that takes a menu or subtitle and blends it to the background in hardware to avoid stressing the CPU with the signal processing that is associated with alpha blending.

Perhaps the biggest addition to ATI's video repertoire for the RADEON is adaptive deinterlacing, a quality feature that blends bob and weave deinterlacing on a per-pixel level for a smoother image. If motion is detected on any given pixel, bob interlacing is used, if there is no motion on the pixel, weave interlacing is used instead. Unfortunately, adaptive deinterlacing isn't recognized by Video 2000, so although we'd love to run MadOnion's video benchmark on the RADEON, the numbers that are returned don't represent actual performance."

Owners of older All-In-Wonder products have complained about the lack of an S/PDIF output for digital audio, the only reason left for picking up a hardware decoder in our eyes. With the release of the RADEON, ATI has decided to include the S/PDIF output, allowing those with Dolby Digital speaker systems to enjoy the full 5.1 experience through the Rage Theater companion chip. While we didn't have such a system available for testing, we were able to connect the All-In-Wonder RADEON to an Onkyo receiver with Dolby Pro Logic processing for an impressive demonstration of The Matrix on DVD.