The DVD Revolution
ATI used Mach64-VT video technology in its next two generations of chipsets, the 3D Rage I and 3D Rage II. February 1997 brought the 3D Rage II+DVD, the card that put ATI at the top of the DVD acceleration world. The 3D RageII+DVD was the first graphics chip to offer hardware motion compensation, which offloaded the most computationally taxing part of software DVD from the CPU to the graphics card.
Practical software MPEG-2 really did not come until the 3D Rage Pro which came out in Spring of 1997. With the added bandwidth of the AGP bus, improved motion compensation, and 4x2 tap video scaler, the 3D Rage Pro offered high-quality software DVD playback on Pentium II class machines in addition to good 3D performance. This powerful combination of features made the Rage Pro the OEM favorite, and in 1998, ATI's annual revenues almost doubled.
ATI temporarily lost the DVD acceleration crown in late 1998 when S3 launched its Savage3D chip. Not only did S3 offer a better performance through a faster motion compensation engine, but S3 had better image quality with a top notch video up-and-down-scaler as well as hardware alpha-blended sub-picture blending, a first.
Sub-pictures are used in DVDs for transparency effects in navigation menus as well as subtitles. The Savage3D's DVD playback looked virtually identical to a standalone DVD player. The Rage Pro had to dither its subtitles and menu options.
ATI Retakes the Lead
ATI answered S3's challenge with the Rage128 GL. Although S3 still had a marginal lead when it came to image quality thanks to the improved down-scaler, the Rage128 GL matched S3's hardware sub-picture blending and also added iDCT support (inverse discrete cosine transfer) in hardware. This added feature further offloaded the DVD decoding computations from the CPU. The Rage128 DVD core would remain largely unchanged for almost two years.
In Spring 2000, ATI announced its current flagship product, the Radeon. This chip added higher performance HDTV-compatible MPEG-2 motion compensation and adaptive de-interlacing, recently enabled for analog video with new drivers. Adaptive de-interlacing displays DVD-Videos with 30fps content (i.e. TV shows) at the highest possible quality.