User Guide User guide

Table Of Contents
VN-MATRIX User Guide Section 4: Advanced Setup Procedures
I458GB issue 6 Page 73
Audio Compression
The S/PDIF digital data bus can carry two types of data:
2 channel (stereo) uncompressed audio, or
encoded digital data, typically AC-3 (Dolby Digital) format.
VN-MATRIX supports limited compression of S/PDIF audio sources. This is controlled by the
Compression setting on the Configure (audioPort) page. The following compression options are
available:
Compression 2 channel audio source AC-3 audio source
no compression 24 bit native data
(2975 kbps)
24 bit native data
(2975 kbps)
compress 1 16 bit data, full sample rate
(1517 kbps)
16 bit data, zeros run length encoded
(430 kbps)
compress 2 16 bit data, 1/2 sample rate
(784 kbps)
16 bit data, zeros run length encoded
(430 kbps)
compress 4 16 bit data, 1/4 sample rate
(418 kbps)
16 bit data, zeros run length encoded
(430 kbps)
NOTE: The native uncompressed setting passes the full 24 bit payload plus the 4 S/PDIF control bits
updating on a continuous frame basis. Other modes only transmit 16 bit data and reduce the
S/PDIF control bits update rate to once per second.