ASAC-Analysis/Synthesis Audio Codec for Very Low-Bit Rates
Bernd Edler, Heiko Purnhagen, Charalampos Ferekidis · 1996
An Analysis/Synthesis Audio Codec (ASAC) is presented, which allows the coding of audio signals at very low bit rates for applications like mobile communication or multimedia database access via modem and analog telephone lines. Compression with bit rates between 6 kbit/s and 24 kbit/s is addressed. Furthermore the implementation of special effects like independent pitch change and speed change in the decoder is described. 1 Introduction Many applications for very low bit rate storage and transmission of digital audio signals mainly focus on speech signals. Therefore a lot of optimizations for speech codecs operating at bit rates between 6 and 16 kbit/s were carried out during the past years. However there is an increasing interest in extensions which also allow the transmission of music signals in areas like mobile communications or multimedia database access via modem and analog telephone lines [1]. The presented Analysis/Synthesis Audio Codec is therefore designed to represent musi...