Design And Implementation Of The Video Capture Playback Card

With the rapid development of Wide Band technology and Stream Media technology, computer users can obtain more and more media resources on net, they not only can download the media file, but also can order programs on demand. With the popularization of TV, Computer and Wide Band, it is more important to impose device that integrates the resoures in existence, exerts fully the potential of each device, gains the most use.On basis of analyzing the product on the market, this paper brings forward a means that is to design a video capture and playback card, which captures video and plays computer files or net files on the TV set in the background. Video capture and playback card utilizes computer software to compress or decompress video and sound. It costs some system resource, but brings the merits include simplier circuit, lower cost, easier upgrade. It uses the PCI interface chip SAA7146A special for media processing produced by Philips, and connects simply with video encoder, video decoder, audio encoder and decoder. Through programming stream minidiver, wrapping hardware device with the wrapper filter in the DirectShow, it implements an access from DirectShow Filters to hardware device. This card, TV set, computer and Wide Band can comprise a full video capture and playback system.This paper shows the whole design scheme and explains each module on the hardware board in detail. According to the step of design the device driver, the paper expounds the design of the basic driver and stream minidriver. At last the paper gives a brief introduce the design of DirectShow application.