Abstract:
After the advent of compact disk the end user has started to expect high quality output
from any digital audio application. The increasing demand of audio transmission and
exchange over the internet and the growing trend of storage/playback of high quality
audio on digital computer systems persistently call for developing new and improved
audio coding techniques which can meet the contradicting demands of high quality
and low bit rate both at the same time. Perceptual audio coding which employs the
process of irrelevancy reduction through exploitation of human auditory perception
has a central place in modern audio coding scenario. In this thesis several new
techniques are developed within the paradigm of perceptual audio coding to enhance
the coding efficiency and produce better output quality at reduced bit rates. The
performance of developed techniques is evaluated by employing both subjective and
objective measures recommended by the ITU-R. Moreover a coding scheme is
developed which integrates the advantages of separately available sophisticated
speech and audio coding techniques within a single algorithm. This codec is intended
to cater for the needs of present multimedia scenario which contains mixed speech
and audio signals thus requiring a single codec to handle all signal types for optimal
coding efficiency.
