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Station Notes
So, you have to get your station on the air with 5.1
channel audio and the network has furnished you with some guidelines and
possibly even some equipment. Where do you go from here? How is everyone
else doing it? This section presents some insights into all of the
terrestrial broadcast networks currently supplying programs with 5.1
channel audio to their affiliates. We recommend that you begin with all
of the information available to you from your network, then supplement
it with information you can find here. If you have additional detailed
questions, please don't hesitate to contact us as we have experience
with all of the networks.
ABC NETWORK
Distribution of ABC DTV
network audio to affiliates uses two-channel MPEG (LtRt) and high-rate
(640 kbps) AC-3 for the 5.1 via a mezzanine compression system (higher
rate than ATSC emission). Local affiliate stations must receive the
network signal, then decode the high-rate AC-3 signal to 5.1 PCM
channels, mix or switch local audio in, then Dolby Digital (AC-3) encode
for emission.
More details...
CBS NETWORK
Distribution of CBS DTV network audio to affiliates uses Dolby E, plus an additional two-channel feed (likely MPEG) via a mezzanine compression system (higher rate than ATSC emission). Affiliate stations must purchase both a Dolby E decoder to get the 5.1 channel program, and also a separate metadata de-embedder.
More details...
FOX NETWORK
Starting with the 2004 fall season, the FOX network has begun sending affiliates a complete transport stream which contains an emission rate (448 kbps) Dolby Digital (AC-3) signal. The network has provided
transport stream splicers to affiliate stations to allow for local content insertion, but as they are sending full-time 5.1 channel audio, the local station has a little more work to do to maintain
consistency.
More details...
NBC NETWORK
Distribution of NBC DTV network audio to affiliates is via MPEG compression built into their mezzanine compression equipment. Affiliate stations receive up to eight PCM channels (stereo or LtRt plus 5.1 channel program), then mix or switch local audio in, and Dolby Digital (AC-3) encode for emission.
More details...
PBS NETWORK
PBS distributes a complete 19.39 Mbps ATSC transport stream to their DTV affiliates. Simply add a modulator, RF amplifier, and antenna and the station is on the air in HD with 5.1 channels of audio. As in the case of FOX network, if a station wishes to insert local programming, it gets a little more complicated.
More details..
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