Samsung S5PC110 Manual page 1628

S5PC110_UM 10 9BHIGH-DEFINITION MULTIMEDIA INTERFACE
10.2.1.5 Non-Linear PCM Encoded Source (IEC 61937)
The non-linear PCM encoded audio bitstream is transferred using the basic 16-bit data area of the IEC 60958
subframes, that is, in time slots from 12 to 27. Each IEC 60958 frame transfers 32-bits of non-PCM data in
consumer application mode.
When the SPDIF bitstream conveys linear PCM audio, the symbol frequency is 64 times the PCM sampling
frequency (32 time slots per PCM sample times two channels).
When the interface transmits non-linear PCM encoded audio bitstream, the symbol frequency is 64 times the
sampling rate of the encoded audio within that bitstream.
In case the interface containing audio with low sampling frequency conveys a non-linear PCM encoded audio
bitstream, the symbol frequency is 128 times the sampling rate of the encoded audio within that bitstream.
Each data burst contains a burst-preamble consisting of four 16-bit words (Pa, Pb, Pc, and Pd); followed by the
burst-payload that contains data of an encoded audio frame.
The burst-preamble consists of four mandatory fields. Pa and Pb represent a synchronization word; Pc gives
information about the type of data and some information/ control for the receiver; and Pd gives the length of the
burst-payload, limited to 216(=65,535) bits.
The four preamble words are contained in two sequential SPDIF frames. The frame beginning the data-burst
contains preamble word Pa in sub-frame 1 and Pb in sub-frame 2. The next frame contains Pc in sub-frame 1 and
Pd in sub-frame 2. When placed into a SPDIF sub-frame, the MSB of a 16-bit burst-preamble is placed into time
slot 27 and the LSB is placed into time slot 12.
Data-burst Stuffing Data-burst Stuffing Data-burst Stuffing Data-burst ...
Pa Pb Pc Pd Burst-payload Pa Pb Pc Pd
Repetition period between two data-bursts
Figure 10-12 Non-linear PCM Format
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