DP564 Multichannel Audio Decoder Appendix B: Latency Values
B-2
Table B-1 shows the SMPTE Standard specified decoder latency with respect to the
first word of the Dolby Digital frame (which is the reference point).
Table B-1 SMPTE-Specified Latency
Sample Rate Decoder Latency with
Respect to Reference Point
48 kHz 32 ms
44.1 kHz 34.83 ms
32 kHz 48 ms
Like the SMPTE professional specification, the IEC consumer specification also
describes placement of the Dolby Digital frame on the S/PDIF interface such that a
decoder with the specified latency will produce correctly timed audio. The specified
decoder latency is exactly one Dolby Digital block period, with respect to the
reference point. Note that since there are six blocks in a frame, the latency
specification is for one sixth of a frame time, or the time span of 256 audio samples.
In the IEC specification, the reference point is defined as the point two thirds of the
way through the frame of Dolby Digital data. Since the frame size depends on the
data rate, the reference point follows the beginning of the frame by a variable amount
based on the data rate.
Table B-2 shows the latency specified by IEC 61937, with respect to the beginning of
the Dolby Digital frame on the S/PDIF interface.