Upmix Engines Stake Out a Place in Sports Broadcasting

Upmixing engines may still be a specialty item, but they have become standard issue in sports-broadcast processing racks. The intention is to provide the most seamless discrete 5.1 surround-sound experience for viewers by making legacy mono and stereo audio elements conform to a multichannel sound field and one that is more consistent when downmixed to stereo for receivers that can’t reproduce surround audio. Here’s a look at some of the leading contenders.

DTS Neural Surround processing is designed to allow seamless conversion between stereo and surround sound. The Neural Surround family comprises UpMix, DownMix and MultiMerge technologies. UpMix transforms any stereo signal into surround sound and can be used to decode stereo or Lt-Rt encoded broadcasts back into surround sound, often indistinguishable from discrete 5.1 content, without affecting the spectral and timbral balance. Neural Surround UpMix can output any channel configuration from 3.0 to 7.1. It also provides creative controls for sound-field width and depth, channel layout, output levels, LFE filtering, and a final limiting.

The Neural Surround DownMix process reduces 7.1 or 5.1 surround sound to a stereo mix that accurately represents the multichannel original. Active correction within the DownMix can fix such issues as comb filtering, spatial location, and distortion, creating a pristine stereo mix that can be re-rendered into surround sound later.

Neural Surround MultiMerge pairs UpMix and DownMix with auto-detection to guarantee surround-sound output for any transmission path. MultiMerge features full-time 5.1 surround-sound output as well as a full-time Lt-Rt stereo output from any content source.

DTS Neural Surround is licensed to broadcast-hardware and -software suppliers such as Harris Corp. and DaySequerra.

Linear Acoustic
Engineered on the foundation of the company’s first- and second-generation DTV audio processors, Linear Acoustic’s AERO.air enables broadcasters to deliver compelling 5.1 surround sound while saving time, money, and space. It is equipped with dual upMAX two- to-5.1-channel upconversion upmixers as well as full-time two-channel downmixing to support legacy stereo or analog paths.

Built-in AutoMAX-II processing detects incoming audio and automatically upmixes only when necessary, producing a full-time 5.1-channel output. The processor accepts 5.1-channel network audio, two-channel local audio, SAP/DVS, and digital or analog auxiliary/EAS audio for processing.

Options available with AERO.air include HD/SD-SDI input for de-embedding any of the possible 16 audio channels and vertical ancillary (SMPTE 2020) metadata, internal 5.1+2 dual Dolby Digital (AC-3) encoders, auto-sensing Dolby E/AC-3 decoding, and CrowdControl dialog protection. The processor also includes ITU loudness control and metadata management. Recent additions include ITU-R BS.1770 meters on all outputs, support for Dolby Digital Plus, optional built-in Nielsen Watermark encoding for up to four programs, and the new UPMAX-II reference upmixing algorithm.

The Penteo PostPro professional stereo-to-5.1 upconversion processor uses the company’s real-time forensic waveform-analysis code to digitally separate individual sounds within a stereo mix into discrete slices, each taking a corresponding position in a 5.1 sound field. The result is an accurate 5.1 interpretation of the original stereo mixer’s work, live or legacy, for music, sports, television, or film. Because Penteo does not alter any phase components or levels, the resulting 5.1 surround-sound mix retains all backward stereo and mono broadcast compatibility.

TC Electronic
TC Electronic’s DB8 DTV quad-engine, 2RU processor can be ordered with SDI and/or AES-3 I/Os. I/Os are expandable to 16 channels of AES-3 or embedded audio. Each of the DB8’s engines can process stereo, dual mono, or 5.1 surround sound. Units running V2.0 software also include TC’s exclusive LM5D loudness meter. Both the DB8 and sibling DB4 (which has the same functionality but with a dual-engine rather than quad processor) provide synchronous 48-kHz sampling and 48-bit processing throughout, in combination with jitter rejection.

Both units allow disabling of the upconversion function when transmitting 5.1 surround-sound feature films, leaving the units’ loudness control and limiting functions in the signal path. Intersample accurate limiting allows tight peak control and maximum audio quality from lossey compression codecs. Distortion canceling and limiting techniques keep distortion to a minimum, allowing the DB4 and DB8 to deliver clean, crisp audio. The standard configuration for each includes eight channels of AES/EBU I/O, balanced or unbalanced. Also available are optional SDI interface and analog I/O cards. The maximum number of separate inputs/outputs is 16.

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