DAI-3206 Instruction Book
Revision 6
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Page 6 of 12
3206-DAI_ib_Rev6.doc
Technical Description
Audio Packet Distribution
Groups are embedded in non-switching lines with each group residing in a fixed number of bytes from the End of
Active Video (EAV) flag. Each group contains either 3 or 4 AES words in length. Preserving this distribution
simplifies insertion or removal of audio groups. Other manufacturers support this method.
In the non-resampled mode, each of the two channels within the AES group must be the same data rate. If both
channels are present, input one is deemed master and the packet distribution is performed according to its input
rate.
Input 1 corresponds to channels 1 & 2 of the audio group while Input 2 corresponds to channels 3 & 4. Note that in
the non-resampled mode, Input 2 may experience clicks or pops and C channel errors if asynchronous to Input 1.
If Input 1 is not present then Input 2 becomes master. If neither is present then no audio packets are embedded.
If both a combination of one AES and one analogue audio pair are used, then the AES input becomes master if
present, else the analogue sampling rate is locked to the SDI clock rate. This is true for the non-resampled mode.
In the resampled mode, both AES and Audio are locked to video.
If both analogue audio pairs are used, the analogue sampling rate is locked to the SDI clock rate.
Group 1
Immediately after EAV.
Group 2
64 bytes after EAV.
Group 3
128 bytes after EAV.
Group 4
192 bytes after EAV.
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