Originally Posted by wb8tgy
I am sorry to hear that WKAR is planning on adding two more sub channels, sure seems like it will degrade both 23.1 and 23.2. Some of the stuff I have recorded from 23.1 are just great looking, and the few HD-DVD's I have been able to make on regular blank DVDs look great also! I do understand that many people like the other channels, as I am guessing that WKAR will be using some of the same programs that WCMU is using. Is WKAR going to turn off 23.3 and 23.4 during prime time or try running them all the time?
As you may have noticed from my earlier post, unlike most commercial stations, public television stations enjoy (employ?) different program rights permissions. We have so much content that we just can't air it all. The CREATE channel we have on Comcast is very popular.
We want to be able to offer a variety of program choices to our viewers (members). If you don't want to watch Barney.... then you can watch This Old House .... or Nova.... or the poor Bismark being sunk by the Hood.
PBS has said that they would be merging the HD channel and the National Program Service into one stream. (Right now they are pretty much independent, with relatively few simultaneous events) This could happen as early as Fall, 2008. (Well, that's the programmer's desires.... but at the moment PBS does not have transponder capacity to accomodate multiple HD channels with the time zone delays.... so either (a) the merger happens later, (b) PBS purchases time zone delay servers for effected stations (Central, Mountain, Pacific, Hawaii/Alaska), or (c) they get the "Next Generation Interconnect" system fully implemented which will allow stations to receive and record 80% of program content two days before broadcast as "files" rather than streamed programs.
I started this latest thread with an inquiry about our new PSIP. In addition to new PSIP generators, we have acquired two new standard-definition encoders, one new multiplexer, and two new multiplex/encoder controllers. We started with two HD/SD encoders and one SD encoder. One of the two HD/SD encoders is a back-up to all of the other encoders.
The existing encoder was upgraded to current specifications (which is actually the one that failed due to lip sync errors).
All the encoders now have "multi-pass" internal encoding to improve their compression efficiency. In addition, we use "statistical multiplexing" so that we can assign priorities to different services (HD more important) such that the multiplexer can change the allocations of bits between services on a frame-by-frame basis.
Between the multi-pass and the statistical multiplexing, assigning different minimum-maximum bit rates to the different services (e.g. Cartoons don't need a lot of bits), along with the 1080i to 720p conversion of the network signal we feel pretty confident that this will work with out killing the quality of the HD service. (I can't say it won't impact it, it will.)
We do not expect to turn off services during different day parts, but we might change the priorities/allocations of the bandwidth assigned to the different services.