Beszédkódolás

Beszédkódolás, also known as speech coding or voice coding, is a technology used in telecommunications and audio processing to compress and represent speech signals efficiently. Its primary goal is to reduce the amount of data required to transmit or store speech, making it possible to send more conversations over limited bandwidth or store large amounts of audio data. This is achieved by exploiting the redundancies and characteristics of the human speech production system.

There are various types of speech coding techniques, broadly categorized into waveform coders and model-based coders. Waveform coders, such as Pulse Code Modulation (PCM) and Adaptive Differential Pulse Code Modulation (ADPCM), aim to reconstruct the speech waveform as accurately as possible. Model-based coders, like Linear Predictive Coding (LPC) and Code-Excited Linear Prediction (CELP), create a mathematical model of the vocal tract and use it to synthesize speech.

The effectiveness of a speech coder is often measured by its bit rate (the amount of data per second), its Mean Opinion Score (MOS), which indicates perceived speech quality, and its computational complexity. Lower bit rates are desirable for efficient transmission, but they can sometimes lead to a degradation in speech quality. The choice of speech coder depends on the specific application requirements, such as the available bandwidth, the desired quality, and the processing power of the devices involved. Applications include mobile phone communication, Voice over IP (VoIP), voice assistants, and audio compression for multimedia.