AJA FS2 Manual - Manual (Page 58)

FS2 v2.1r1 www.aja.com 58
In Manual mode, the sample rate converters are enabled manually for each AES pair
using parameters 14.1 through 14.8.
In Auto mode, the system decides how to handle sample rate conversion. Normal PCM
audio passes through the Sample Rate Converters and gets converted, as appropriate.
AES channels in which the non-audio flag is set in the Channel Status Word are
automatically detected and allowed to bypass the Sample Rate Converters; the signal
passes unaltered and the existing data is preserved.
14.1–14.8 AES/EBU
SRC
This group of parameters controls audio sample rate conversion on AES/EBU input audio
channel pairs 1/2, 3/4, 5/6, 7/8, 9/10, 11/12, 13/14, and 15/16.
When 14.0 AES/EBU SRC Mode is set to Auto, no settings per channel are required;
sample rate conversion occurs normally for all channels unless the non-audio flag is set in
the Channel Status Word, in which case sample rate conversion gets bypassed and the
signal is passed through unaltered.
When 14.0 AES/EBU SRC Mode is set to Manual, each channel pair can be set manually to
On or Bypass. using parameters 14.1–14.8.
On is the default setting in which audio is rate-converted and synced with video (SRC is
applied).
Bypass is available for use when Dolby ® 5.1 and similar schemes need to be preserved and
the audio data passed unaltered (no SRC is applied).
Set these parameters to Manual (14.0)and Bypass (14.1-14.8) only if BOTH the following
items are true:
• You want to pass unaltered digital encoded audio from either an embedded or AES
Input to an embedded and/or AES Output.
• You have the embedded or AES input genlocked to the FS2 output. In other words, the
encoded audio will not survive the frame-sync function (dropping or repeating frames)
so it needs to be set to lock to the input. You can lock to a reference only if that
reference is driving both the FS2 and the upstream source of the embedded or AES
input to the FS2.
Auto (default)
Manual
The signal bypasses the Sample Rate Converters for audio channels
containing a non-audio flag in the Channel Status Word. If the
non-audio flag is not set, the signal passes normally through the
Sample Rate Converters.
The FS2 determines what to do about audio sample rate conversion
on a channel pair-by-pair basis, determined by settings 14.1-14.8.
If a channel pair is set to On, sample rate conversion is applied to
that channel pair. If a channel pair is set to Bypass, the FS2 leaves
embedded audio as is, bypassing sample rate conversion; this is
useful for Dolby® 5.1 embedded audio and other applications
where you do not want sample rate conversion to occur.
On (default)
Bypass
Audio sample rate conversion (SRC) is applied to the affected
channel pairs and keeps the video and audio synchronized.
Audio sample rate conversion (SRC) is NOT applied to the affected
channel pairs. The signal is passed through unaltered, which is
useful for preserving Dolby® 5.1 embedded audio and other
applications where existing data on the input must be preserved
and passed to the output.