文件名称：BT.656 Format
文件大小：137KB
文件格式：PDF
更新时间：2012-01-08 08:17:55
BT.656
Introduction When ITU-R BT.601, formally CCIR-601, was developed (which defined the YCbCr color space, the 4:2:2 YCbCr sampling organization, and sampling resolutions), it was soon followed by ITU-R BT.656 (formally CCIR-656). BT.656 defined the parallel and serial interfaces for transmitting 4:2:2 YCbCr digital video between equipment in studio and pro-video applications. Active video resolutions are either 720 x 486 (525/60 video systems) or 720 x 576 (625/50 video systems). The BT.656 parallel interface uses 8 or 10 bits of multiplexed YCbCr data and a 27MHz clock (ECL levels are used for the data and clock signals). Instead of the conventional video timing signals (HSYNC, VSYNC, and BLANK) also being transmitted, BT.656 uses unique timing codes embedded within the video stream. This reduces the number of wires (and IC pins) required for a BT.656 video interface. Ancillary digital information (such as audio, closed captioning, and teletext) may also be transmitted during the blanking intervals. This eliminates the need for a separate audio interface and additional control signals.