# 7.1 Source coding

## Introduction

The purpose of source coding is to transform the information type in the source to a form best suited to the transmission process. Often this involves converting an analogue signal such as voice or light intensity in an image to a digital binary representation for transmission using a modem. |

These days, the source coding process will usually implement an algorithm to realize bit or symbol content compression in addition to the standard process of quantization and A/D conversion. Standard image compression algorithms are the MPEG and JPEG formats for moving and static images respectively. At the present time, the source coding for music and speech is not so well standardized, with many different formats in use throughout the world. In most, but not all cases, a complementary decoder is implemented to restore the signal to near or exactly its original format.

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