What will MPEG-4 Audio provide above MPEG-2 Audio?
MPEG-4 Audio will integrate the worlds of synthetic and natural coding of audio. The synthetic coding part is comprised of tools for the realisation of symbolically defined music and speech. This includes MIDI and Text-to-Speech systems. Furthermore, tools for the 3-D localisation of sound are included, allowing the creation of artificial sound environments using artificial and natural sources. MPEG-4 Audio also standardises natural audio coding at bit rates ranging from 2 kbit/s up to 64 kbit/s. In order to achieve the highest audio quality within the full range of bit rates, three types of codecs have been defined: a parametric codec for the lower bit rates in the range, a Code Excited Linear Predictive (CELP) codec for the medium bit rates in the range, and Time to Frequency (TF) codecs, including MPEG-2 AAC and Vector-Quantiser based, for the higher bit rates in the range. Furthermore, a number of functionalities are provided to facilitate a wide variety of applications which would
