Aes audio input advanced features, Documentation terms, Discrete aes audio output – Sierra Video ADC-142 User Manual
Page 9: Aes sample rate converter bypass, Zero-delay audio embedding, Low latency aes passthrough
ADC-142 Owner’s Manual •••• (V 2.1)
Page 9 of 29
Discrete AES Audio Output
The ADC-142 can emit 16 channels (8 pairs) of discrete AES audio on 75 ohm BNC connections. The
AES clock rate will be precisely locked to the output video rate.
AES Audio Input Advanced Features
AES Sample Rate Converter Bypass
The card’s AES inputs have built in sample rate converters that are enabled by default. This allows the
card to interface with asynchronous AES sources (sources who’s AES timing does not match the video
reference timing.). They can be bypassed with a control in Dashboard or the front panel. This is a
necessity when trying to embed non-PCM AES audio such a Dolby E or Dolby Digital audio streams.
This control is off by default.
Zero-Delay Audio Embedding
Sometimes it is desirable to embed AES with minimum latency. For example, if you want to embed
Dolby E audio into video with no latency, and delay the video by one frame to account for Dolby E
encoding delay. By turning this control on for a given AES pair, the pair will be directly embedded into
it’s corresponding group, bypassing the normal frame sync audio delay. (AES Pair 1 into Embedded
Group 1, ch1 & ch2, AES pair 2 into Embedded Group 2, ch3 & ch4). This control overrides the
standard audio routing system: if AES Pair 1 is selected, then the controls to route into Embedded
group 1, ch1 & ch2 don’t apply. There is no gain or polarity control available when this option is
selected. This control is off by default
Low latency AES Passthrough
This control is similar to zero delay audio embedding. If selected for input pair X it causes AES output
pair X to act as a bit for bit copy of AES input pair X. This over rides the normal audio routing and
delay. No gain and polarity adjustments are possible. This control is off by default.
Documentation Terms
The following terms are used throughout this guide:
•
“Frame” refers to the 8310 frame that houses the ADC-142 card.
•
“Operator” and “User” both refer to the person who uses the ADC-142.
•
“Board” and “Card” all refer to the ADC-142 card itself, including all components
and switches.
•
“System” and “Video system” refers to the mix of interconnected production and
terminal equipment in which the ADC-142 operates.