MultiDyne Solves Audio Downmix Problem for KAMU-TV
COLLEGE STATION, Texas—Texas A&M University is home to KAMU-TV and FM, the major PBS and NPR affiliate stations serving College Station and the Brazos Valley. With coverage in the Waco, Temple and Killeen markets, we reach thousands of viewers and listeners wirelessly, including three digital television channels (national PBS programs, Create and PBS Kids).
PBS continues to expand its streaming presence to reach more viewers through initiatives like PBS Passport, which offers members expanded access to on-demand programming. PBS also offers free live TV streams PBS.orgEmbedding the local member station’s feed in a branded web player (as in “KAMU Livestream”).
downmixing issues
A recent change in national PBS broadcast systems caught the attention of KAMU livestream viewers, which turned into a troubleshooting mission to fix a confusing audio issue. PBS has made a change to the technological infrastructure of its centralized coding system, which routes live TV streams to member stations’ web players.
The previous system automatically downmixed the audio from 5.1 broadcast programs to a 2.0 stereo mix for web streaming at the handover point from the encoder. As one of the first stations to be added to the new scrambling infrastructure, we were soon receiving calls from KAMU livestream viewers that they could only hear strange noises. We quickly confirmed that channels one and two of the 5.1 surround feed were getting through and found we had a downmix issue.
We knew right away that we wanted a problem-solving device that we could plug in to fix the problem. Given the limited budget and technical resources, we wanted to avoid complex software solutions with downmix appliances that require extensive configuration, testing, and fine-tuning to consistently downmix audio. We soon came across MultiDyne and its distribution and conversion products, the NanoBrix series, which includes a specialized audio product specifically designed to downmix surround audio to stereo.
Plug
The NanoBrix NBX-5.1-DMX-PCM-3G is a miniature hardware downmixer that accepts embedded discrete multi-channel audio and re-embeds a converted stereo downmix on the processed SDI output. The design is simple, with an input to capture the SDI signal, an SDI output with the embedded, processed audio, and a second reclocked output. This allowed for a quick plug-and-play installation. The downmix problem was solved when connecting.
The beauty of this product is that the problem has been solved permanently. As mentioned, we wanted to avoid software solutions that require monitoring and fine-tuning of settings. The NBX-5.1-DMX-PCM-3G positions two bi-color LEDs on the front of the device that indicate the presence of a valid SDI video signal and the presence of embedded audio in that signal.
Like a traffic light, a green glow confirms everything is moving forward, while a red glow indicates the signal has stopped. This allows for easy and straightforward signal monitoring in case we need to troubleshoot. Up to this point, the lights remain solid green.
The NBX-5.1-DMX-PCM-3G downmixer fits seamlessly into our studio infrastructure. The program audio is output from our master control switcher and into our router. The router forwards the audio feed to the NBX-5.1-DMX-PCM-3G, which downmixes the audio and sends it back to the router. From there, the stereo feed is sent to our primary and secondary encoders, which power the PBS infrastructure for the KAMU livestream viewers.
We also like the fact that this product will automatically do the same job when we extend our streaming architecture to other encoders since it’s already part of our routing system. The NBX-5.1-DMX-PCM-3G is therefore not just a cost-effective and easy way to solve downmix problems today, but a future-proof solution for new downmix requirements to be added in the future. l
For more information visit www.multidyne.com.
