2x Vistek probel Cifer HDSDI  high definition  standards converters with Dolby audio.  

Accepts HD / SD input signals

Cifer also handles many other forms of auxiliary data, such as Closed Captions, Source Identification and Time Code.

https://wwwapps.grassvalley.com/docs/Manuals/sam/modular_infrastructure/Vistek/Vistek%20V6481%20Cifer%20HD%20Video%20Converter%20v2.0.pdf

Vistek modular frame with 2x V1610 power supplies

installed with 2x high definition Standards converters

Each standards converter has the following

1x main v6481 HD standards converter card

1x V6482 HD motion estimator

1x V6302 Advanced audio processor

2x V6991 fan cards