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数字技术就是用数字编码来描述和表达图像、声音及各种媒体信息。其信息处理的流程是:模拟信息→数字化→压缩编码→存储或传输→解码再现。其中,压缩编码是一个关键的环节。当我们将视频和音频模拟信号进行采样并分别进行模/数转换,则这些视频、音频信号就成为数字化的信息流,但这些信息流是不能直接进行传送和存储,因为未经压缩的图形、视频和音频需要非常大的存储容量,一幅640*480像素、中等分辨率的彩色图像(24bit/像素)的数据量约为7.37Mbit/帧。所以,必须对数字化信息进行压缩,用尽可能少的数据来表达信息,为此,很多压缩编码标准相应推出。目前市面上主要的压缩编码标准有 JPEG/M-JPEG、H.261/H.263、MPEG 系列等标
Digital technology is the use of digital coding to describe and express images, sounds and various media information. The process of information processing is: analog information → digitization → compression coding → storage or transmission → decoding and reproduction. Among them, the compression coding is a key part. When we sample video and audio analog signals and perform A / D conversion separately, these video and audio signals become digitized streams, but they can not be transferred and stored directly, because uncompressed graphics, Video and audio require very large storage capacity. A 640 x 480 pixel, mid-resolution color image (24bit / pixel) has an approximate data rate of 7.37Mbit / frame. Therefore, it is necessary to compress the digitized information and express the information with as little data as possible. For this reason, many compression coding standards are introduced accordingly. Currently the main compression coding standards on the market are JPEG / M-JPEG, H.261 / H.263, MPEG series and other standards