Grass Valley AMX-3981 2014 - Manual (Page 7)

GUIDE TO INSTALLATION AND OPERATION
AMX-3981 | 1
1 AMX-3981 3Gbps/HD/SD 8 AES Audio & Metadata Embedder
1.1 Introduction
The AMX-3981 is an advanced, high quality audio processor which embeds up to eight (8) AES signals into a
3Gbps/HD/SD video signal. Each AES input can accept different sample rates, or even asynchronous audio, and will
be resampled at 48 kHz by a sample rate converter, which can be manually or automatically disabled in the presence
of non-PCM audio.
The AMX-3981 can simultaneously process up to 32 channels of audio (16 channels from the discrete AES inputs,
and 16 channels of embedded audio). Functions include down-mixing, Proc Amp, channel shuffling and mixing.
Options include Automatic Loudness Control, dynamic processing (limiter, compressor, and expander) and loudness
measurement. The AMX-3981 generates audio/video fingerprints (via an iControl option) to detect and measure lip-
sync errors in a broadcast facility.
The new loudness measurement option allows the measurement and logging of up to 4 audio programs with iControl
Loudness Monitoring software to analyze and report compliance with respect to various loudness legislations around
the world (See iControl Loudness Monitoring).
The AMX-3981 has one on-board socket for optional modules, including Dolby E and Dolby Digital decoding,
upmixing using Linear Acoustic upMAX™ technology, Dolby E encoding, Dolby Digital and Dolby Digital Plus
encoding. In addition to Miranda’s own automatic loudness control (ALC) solution for up to eight programs, the AMX-
3981 offers ALC
using the AEROMAX™ technology by Linear Acoustic , or Level Magic™ by Jünger Audio,
implemented using optional modules.
The card will pass and delay automatically all 32 internal audio channels to preserve lip-sync between the channels.
Each channel can be delayed independently to correct any lip-sync issues. All audio channels can be mixed and
shuffled to provide 16 channels for embedding in the video output.
An Automatic Preset Recall feature provides basic automation to select user preset based on the status of the
incoming audio.
When genlocked to the frame reference using the internal URS signal, the AMX-3981 can handle video hot switches
at the input without losing sync at the output. In the absence of a video input, the card can still output synchronous
video and embed the discrete AES audio.
The card has a frame buffer (not a frame sync) which allows an increase in the video delay of up to 15 frames to
compensate for the long audio processing delay required by some modules. For applications which require a small
processing delay, the frame buffer can be bypassed to reduce the delay to a few micro-seconds.
The AMX-3981 can embed Linear Time Code (LTC) as ancillary Time Code (ATC) in 3Gbps/HD and DVITC in SD. Up
to 3 GPIO can be used as input, or output, to embed or extract GPI events to/from the Time Code user bits in
transport applications. They can also be used simultaneously to trigger the card’s user presets.
Dolby Metadata insertion in the VANC is possible from multiple sources, such as a Dolby E decoder module, an
embedded VANC stream, an external RS-422 link, or from the integrated Metadata generator. All parameters in the
Metadata stream can be probed and monitored. Dolby Metadata can be used to steer the behavior of the audio
downmix and upmix modules.
A fiber input/output cartridge is offered as an option on some rear modules. Once the cartridge is installed, the inputs
or outputs are selectable through the control interface. The input of the card allows you to select between fiber and
copper inputs. The outputs are via copper and fiber simultaneously (with appropriate fiber cartridge).