CURVEBALLS AND CROWD NOISE IN STREAMING SPORTS

Peak control, same but different for streaming: Transient peaks are a problem for streaming, same as for on-air, and you’ll need a limiter to catch any overshoots. But not any limiter will do. You’ll need a limiter designed for streaming, one that is not so aggressive as to create distortion that can have a multiplying effect on encoders. Encoders are designed to lose as many bits as possible to get programming down as many links as possible, and the goal is to hang on to all the ones that matter. For our streaming appliances Streamblade, Wheatstream and new Wheatstream Duo, we use a two-band final limiter that’s designed to hold programming below 0dBFS, the point at which streaming codecs run out of bits. By separating final limiting into two bands above and below 180Hz, we can more easily manage pop flies and other peak overshoots without the ‘pumping’ or other artifacts that can further degrade the quality of audio passing through the codec. 

Bring your A game to noise and level correction. There will be noise and there will be screaming, that’s all part of the game, right? You’ll need a few audio tools, starting with a good AGC. The conventional approach for handling wide swings in audio levels is to apply multiband gain control followed by fast compression to build uniform levels. But careful: aggressive gain control can interfere with the performance of the codec. Fast time constants (hard compression) add intermodulation byproducts, which the codec has to spend bits on instead of the actual program content you want to get across. That can be bad for any stream, but it’s especially bad for low bitrate streams. Instead, for our streaming appliances, we use a five-band AGC with RMS density driven time constants to smooth out transitions and to feed the encoder a steady diet of consistent audio levels.

Our streaming appliances also have a two-stage phase rotator to correct voice asymmetry, selectable high- and low-pass filters for removing noise and hum, and four-band parametric equalizer with peak and shelf functions for getting as much quality as possible across a variety of links. You’re going to need all of that during game day!  

Seriously, if you haven’t done so already, go Linux.  Streaming off a Windows® desktop computer isn’t doing you any favors, not for streaming in general and certainly not for streaming content as rich as sports. A dedicated Linux appliance made specifically for streaming is more reliable, more adaptable, and much more audio-friendly. Plus, you can get a Linux streaming appliance like our Wheatstream Duo for about the same cost as a PC and have all the processing tools and all the metadata support you need in one reliable unit.