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Chapter 3
Input Modules
Notes:
ADS Clean
In all modes of operation (Framesync/Delay/Demux-only mode), ADS Clean set to Yes
wipes out all HANC data with the exception of EDH (SD only).
When a channel is operated in Framesync mode or if a board without a Framesync
license (Demux-only) has the ingested SDI signal already locked to the reference signal
applied to the board, the Audio Embedder re-populates the HANC space with Audio
data coming from the Audio processor. In order for the Audio Embedder to re-populate
empty HANC space, the group embedding mode has to be set to either 'Auto' or
'Append'. Overwrite only applies if there is 'something' to overwrite.
When operating a channel in Framesync mode, use ADS Clean with extra caution
because it wipes out any non-PCM Audio data (Dolby E/D) which is lost forever.
Non-PCM Audio data is not re-embedded by the Audio Embedder, since all non-PCM
data bypasses the Audio processor altogether. With ADS Clean set to 'Yes', non-PCM
Audio data will no longer appear in the outgoing SDI stream or show up in the TDM
stream going to the Audio crosspoint. To counter this, a new Audio Synchronizer IP is
required where the clock domain transfer of Dolby data (by dropping or repeating a
frame worth of Dolby data) happens in the Audio Synchronizer's memory rather than in
the Video Frame-synchronizer's memory.
Word Length
The
Word Length (x8)
16, 20, or 24 bits on a per SDI channel basis. 20 bits is the default and is applicable
when the video standard is SD-SDI (525/625).
If the SD-SDI Video has extended Audio packets (which can apply to any of up to four
groups of embedded Audio), Audio data embedded in such group(s) should have a
word length of 24 bits. When the processed audio data word length is 20 bits
(determined by parameter 'Word Length' parameter), the Audio Embedder cannot
overwrite existing extended Audio packets. There are 2 options in this case:
Turn on ADS Clean prior to re-embedding new Audio data, to wipe out any
existing Audio packets (regular and extended).
Set the
Word Length (x8)
word length of the Audio data embedded in the incoming SDI stream.
The Word Length bits for processed Audio data are not auto-detected (based on the
detected word length of the embedded Audio data) and set. This is to allow the
flexibility for users to steer the word length of the re-embedded Audio data such that it
matches the word length of Audio data that originates from a different source (for
example, Audio received via TDM).
Group Active Channels
Due to the absence of audio control packets in SD-SDI modes, there is no (easy) way for
the Audio De-embedder to figure out whether channels within any of the present
groups are active or not. This is why in SD-SDI modes, even if audio channels are active,
their presence is reported as 'None/Unknown'. There is not enough room in the control
space to extend the number of choices in order to notify the user that the information
is not available because of the SD format.
parameter can be set through the Audio section of the GUI to
parameter for the SDI channel in question to match the
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