Multicasting is degrading over-the-air HD broadcasts
Some over-the-air (OTA) television broadcasters are actually degrading the quality of their HD broadcasts to reduce the bandwidth needed to pass along the signal says Broadcasting and Cable.
But increasingly it is local broadcasters, not multichannel operators, that are degrading their hi-def picture quality. The culprit is multicasting, i.e., transmitting digital subchannels alongside the primary HD stream within a station’s 19.4 Mbps digital TV pipe. While such subchannels are finally starting to gain traction and generate meaningful revenues (see Station to Station, June 22), many are doing so at the expense of the high-definition images that were the primary impetus for the DTV standard. Engineers and HD aficionados note, with considerable irony, that while there is far more HD content available today, the relative picture quality may not be as good as the first HD broadcasts more than a decade ago.
In a related story, some of our forum members have experienced picture quality issues with their satellite service, possibly linked to the extra programming being offered at reduced quality. Link to post: http://www.dtvusaforum.com/directv/3307-directv-decreased-quality-compression-artifacts-2.html