  This paper introduces a novel adaptation approach for first-order pre- and
de-emphasis filters, an essential tool in many speech and audio codecs to
increase coding efficiency and perceived quality. The proposed zero-bit
self-adaptation approach differs from classical forward and backward adaptation
approaches in that the de-emphasis coefficient is estimated at the receiver,
from the decoded pre-emphasized signal. This eliminates the need to transmit
information that arises from forward adaptation as well as the signal-filter
lag that is inherent in backward adaptation. Evaluation results show that the
de-emphasis coefficient can be estimated accurately from the decoded
pre-emphasized signal and that the proposed zero-bit self-adaptation approach
provides comparable subjective improvement to forward adaptation.
