MPEG Decoder Requirements

[This is preliminary documentation and subject to change.]

The video card for the MPEG decoder must have the following features:

• Super Video Graphics Array (SVGA) card capable of at least 800 x 600 x 8 bits per pixel, with a 60 hertz refresh rate.
• Support for high-speed, two-dimensional graphics acceleration, preferably with support for three-dimensional bitmaps and MPEG textured polygons.
• MPEG-2 decoder chip set, capable of a speed of 15 megabits per second and a screen resolution of 720 x 480 x YUV 4:2:2.
• Data transfer using bus mastering from memory to the MPEG decoder, at up to 2 megabytes per second in speed. Such transfer must include support for unaligned, odd byte transfer and scatter/gather memory access.
• Capture and display of each 720 x 240 video field stretched vertically to 720 x 80 without decimation.
• Broadcast cable television tuner that supports NTSC or PAL signals.
• Composite super VHS (SVHS) – type chip that decodes NTSC or PAL to YUV, with an interface to the SVGA chip set.
• Composite SVHS-type chip that encodes data to NTSC or PAL, with a direct interface from the MPEG decoder.
• Audio and video crossbar switching chips for interconnecting composite and SVHS inputs and outputs.
• SVGA format that supports capture of YUV frame buffers for prioritized overlay and scaling with horizontal and vertical interpolation.
• Merging of YUV video frames and SVGA video frames in the digital to analog converter (DAC) using chroma and color keying.
• Controllable Macrovision video encoding of all composite video signals that are output.
• Decoding of vertical blanking interval (VBI) data for NTSC format, including decoding of such information as closed captioning, from all composite inputs.
• Encoding of NTSC VBI data (such as closed captioning or time codes) on all composite outputs.
• Full driver support for the Microsoft® Windows® 98 operating system, including display driver and MPEG minidriver support.
• Support for the output of audio from video sources to the line input of standard audio cards.