hangkódolás

Hangkódolás, also known as speech coding or voice encoding, refers to the process of converting an analog audio signal, specifically speech, into a digital representation. This digital representation can then be stored, transmitted, or processed more efficiently. The primary goal of hangkódolás is to reduce the bitrate of the speech signal while maintaining acceptable perceptual quality. This is achieved by exploiting the characteristics of human speech, such as its redundancy and predictability.

There are several types of hangkódolás techniques, broadly categorized into waveform coders and model-based coders. Waveform coders aim to accurately represent the shape of the speech waveform. Examples include Pulse Code Modulation (PCM), Differential Pulse Code Modulation (DPCM), and Adaptive Differential Pulse Code Modulation (ADPCM). Model-based coders, on the other hand, attempt to model the human speech production system. These include Linear Predictive Coding (LPC), Code-Excited Linear Prediction (CELP), and Algebraic CELP (ACELP).

The choice of hangkódolás technique depends on the desired balance between bitrate, speech quality, and computational complexity. Lower bitrates are typically required for applications like mobile telephony and voice over IP (VoIP), where bandwidth is limited. Higher bitrates can provide better quality but consume more resources. The field of hangkódolás is continuously evolving, with ongoing research focused on developing more efficient and robust methods for speech compression.