Brooktree (San Diego, CA, (619) 452-7580) plans to take multimedia integration a step further by combining video, graphics, and audio data within its BtV MediaStream chip set. The chip set supports accelerated graphics at up to 1280- by 1024-pixel resolution, 16-bit stereo sound, and full-motion (30 fps) video windows. A single media controller caches audio, video, and graphics data types into a common buffer (called the MediaBuffer). The video-memory-based MediaBuffer feeds a special RAMDAC (dubbed the PACDAC) that can store packetized data.
All multimedia data is converted into small data packets that stream across a high-speed internal bus and are stored in the MediaBuffer (see the accompanying figure). Audio packets are passed back thro
ugh the controller to the audio chip. The compressed display data consists of separate graphics, video, and cursor packets that flow along a 200-MBps bus to the PACDAC.
The MediaBuffer is logically separated into a graphics frame buffer and a video frame buffer, so that video and graphics can remain in their own color space. The PACDAC performs color-space conversion and video scaling as it sends the RGB data to the screen. Retaining separate color spaces enables graphics and video to display at independent color depths. Video can remain in its most compact format until converted by the PACDAC. A MediaStream-based graphics card will be able to support 1024-by 768-pixel by 256-color resolution on the Windows desktop while also displaying true-color video playback in a window.
Brooktree will target BtV MediaStream at both the add-in card market and as a motherboard component of PCI-based Pentium PCs.
Brooktree's BtV MediaStream
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Packetized Multimedia
