Circuitry, embodied in a media subsystem (10A), reproduces a speech or
other type of audio signal, and is operable when playing back audio data
for reducing synchronization delay. A method operates by, when a frame
containing audio data is sent to a decoder (20), measuring the
synchronization delay; determining by how much the synchronization delay
should be adjusted; and adjusting the synchronization delay in a
content-aware manner by adding or removing one or more audio samples in a
selected current frame or in a selected subsequent frame so as not to
significantly degrade the quality of the played back audio data. When the
synchronization delay is adjusted by more than one audio sample, the
adjustment can be made by all of the determined audio samples in one
adjustment, or the adjustment is made by less than all of the determined
audio samples by a plurality of adjustments. The step of adjusting
selects, if possible, an unvoiced frame and discriminates against a
transient frame. The step of determining includes measuring an average
amount of time that a frame resides in a jitter buffer (18), and
adjusting the synchronization delay so that the average duration
approaches a desired jitter buffer residency duration.