Beszédkódolást

Beszédkódolást, also known as speech coding, refers to the process of compressing and reconstructing digital speech signals. The primary goal of speech coding is to reduce the amount of data required to represent speech while maintaining acceptable quality. This is crucial for efficient transmission and storage of voice communications, especially in bandwidth-limited environments like mobile phone networks or for archiving large amounts of audio data.

There are various types of speech coding techniques, broadly categorized into waveform coders and vocoders. Waveform coders aim to reproduce the waveform of the speech signal as closely as possible. Examples include Pulse Code Modulation (PCM) and Adaptive Differential Pulse Code Modulation (ADPCM). Vocoders, on the other hand, model the speech production process, focusing on parameters like pitch and spectral characteristics. Linear Predictive Coding (LPC) is a well-known vocoder technique.

The choice of a speech coding algorithm depends on the desired trade-off between compression ratio, speech quality, and computational complexity. Lower bit rates generally result in lower speech quality, while higher bit rates preserve more of the original speech characteristics. Modern speech coders, often referred to as hybrid coders, combine elements of both waveform and model-based approaches to achieve better performance. Standards like G.711, G.729, and AMR (Adaptive Multi-Rate) are widely used in telecommunications.