High quality audio for multimedia: key technologies and MPEG standards

With today´s speech and audio compression techniques an excellent coding quality can be obtained with bit rates in the range of 0.5 to 2 bits per sample and channel. We cover key technologies, in particular auditory masking and perceptual coding, and dynamic bit allocation. We then focus on the MPEG standardization work, which has provided international standards for a wide range of multimedia applications. It is then shown that the MPEG-2 Advanced Audio Coding (AAC) standard offers a collection of very flexible tools for stereo and multichannel coding. In addition this standard outperforms many other coding algorithms (including the popular MP3 coder). We also address the current MPEG-4 speech and audio coding standard which merges the whole range of audio from high fidelity audio coding and speech coding down to synthetic audio, synthetic speech and text-to-speech conversion