视频解码原理（Video decoding principle）.docVIP

视频解码原理（Video decoding principle） Recently, because of the video processing, so much deal with decoding chip, decoding chip datasheet has a lot of content, Its hard to understand video processing technology, but after seeing too much, they find most of their structures for decoding chips, Basically the same. Macrovision standard Macrovision standard is mainly used for APS (analog protection system), with composite Or S-Video (Y/C) output terminals for computer video cards must use APS. Macrovision color burst signal fast modulated (color) and vertical blanking signal (AGC) To the composite and S-Video output, this will interfere with synchronous circuit and automatic recording function, so as to protect. However, this reduces the quality of the picture, will cause the color, deformation, swing, the black and white image, light and dark. Lets talk about the basic principles: SAA7115 general functional description: SAA7115 is a video capture device that can be used in a variety of applications, such as small screen devices to large screen devices. The SAA7115 consists of two analog processing circuits, an automatic clamp circuit and a gain control circuit, and two clock generation circuits A combination of Multi Standard decoder. The analog processing circuit includes the selection of video source and antialiasing filter A/D conversion. The multi standard decoder contains a 2 dimensional chrominance / luminance separation. The basic principle of this decoder is line locking (line-locked) decoding operations that can decode PAL, SECAM, and The color of the NTSC signal to the color values in the ITU-601 format. SAA7115 can receive analog signals in the form of CVBS or S-Video (Y-C) signals. The X port of digital video (D1, half duplex, full duplex) can be used to output 10 bit or 8 bit without changing view Frequency data can also be used to connect external digital video sources to use SAA7115s scale capabilities. SAA7115 I port, support 8 bit data output (16), can be c