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Linear Acoustic Announces StreamStacker-HD System

Linear Acoustic has unveiled its StreamStacker high density audio distribution system, which comprises the Model 5173 encoder and the Model LA-5174 decoder. Using advanced multiplexing and coding technologies, more than 20 channels of PCM and emission rate audio can be combined with audio metadata and user definable auxiliary data, and then carried on a single AES/EBU-format digital pair.

SMPTE 302M and 337M-340M specify the carriage of AES signals within MPEG transport streams. The StreamStacker-HD system partitions this data in a way that is determined by user setups derived from the Model LA-5173 encoder. Up to 16 channels of PCM audio can be input to the encoder as eight AES pairs or through HD or SD-SDI. “Alternately, emission rate audio programs—AC-3, AAC-Plus, or DTS-LR—can replace some or all of the PCM channels, allowing a custom mixture of programs in formats most suited for a given application,” adds Linear Acoustic president Tim Carroll.

Metadata functionality, which is controlled via remote, includes internal generation and regeneration of both legacy and advanced audio metadata. Audio metadata input to the system can be provided via the legacy 9-pin RS-485 format or within the VANC space of the HD-SDI input. Digital monitor outputs are provided to allow for important audible preview of metadata settings. User defined data, such as PSIP or Closed Captioning data, can be input via a 100 BASE-T Ethernet connection. Control is provided by parallel GPI/O and Ethernet connectivity.

The Model LA-5174 decoder follows the “stacked” input stream and de-multiplexes signals to their appropriate outputs. Emission rate programs are output as standard AES-3 signals re-timed to local plant reference and ready for insertion into the station’s DTV encoder just as if they were encoded locally, thereby saving the cost of multiple local emission audio encoders. PCM channels are available as AES-3 signals and/or re-inserted into an HD or SD-SDI signal applied to the unit.

Metadata output is available on a standard 9-pin connector for interfacing to products supporting audio metadata via serial input, and can also be embedded into the VANC space of an HD-SDI signal applied to the unit. Internal metadata generation is provided for cases where incoming metadata might be absent or incorrect.

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