数字视频ASIC中OSD系统的实现

介绍1款视频处理ASIC芯片中OSD系统的设计方案,先读取OSD内部SRAM中的属性和字符内容,然后控制电路根据属性将字符内容以RGB的形式表现出来,最后将OSD信息与视频内容进行α混合,从而可以在屏幕上得到OSD信息。该OSD系统用户自定义性强,使用改进的内部SRAM中1/2/4像素深度(BPP,Bits Per Pixel)字符或图形点阵的存储结构以提高字符或图形存储量,其具有闪烁、阴影、透明、单个字符宽高加倍、非线性放大、可编程的行列数和颜色等诸多功能。芯片在UMC0.18μm CMOS工艺下流片,其OSD系统的工作频率可达170 MHz。

Design and Implementation of OSD in Digital Video Processing ASIC

A new OSD system is designed in a digital video processing ASIC which can be applied in modern TV sets and monitors.It reads fonts and attributes contents from build-in SRAM,then represents OSD information by RGB datas according to its attributes,a alpha blending engine will overlay OSD information onto video according to programmable alpha value at last.Many functions of this OSD engine are user-defined,it adopts the proposed storage structure of 1/2/4 bpp fonts and characters in build-in SRAM to support more number of fonts or characters.It can execute non-linear scale up display,as well as vast specific functions such as flashing,shadowing,transparency,fonts or characters double height or width,programmable columns and rows and so on.The chip is designed and fabricated by UMC 0.18 μm CMOS process,and the OSD engine can work well at frequency reach up to 170 MHz.