[BC] For the TV guys for Cowboy

[Gary Cavell]

Harold said: "I still don't see why I get TV 12.1 perfectly and 12.2 drops
out. Aren't these just different packet streams in the same bitstream? Or,
is it like someone suggested where the different packet streams have varying
amounts of error correction (FEC)? "

 

The TV folks here in my office suspect there could be several reasons for
the 12.2 dropping out when the 12.1 doesn't.  While all of the streams (.1,
.2...and even up to .10, believe it or not) reach the transmitter at the
same time, they start out as individual streams that are encoded and then
multiplexed together in the 19.2939 Mbps stream.   Each separate stream has
its own PIDs, PMTs, (and all of the other alphabet soup). 

Some of the possibilities:

 

.         That the statistical multiplexer ("stat mux") is set to favor the
.1 channel, because it's HD and needs more bandwidth to look decent.  The
other channels are compressed down to pretty small streams - think about how
the zillion channels of DirecTV look - kind of blocky and pretty terrible.

.         That the encoder (prior to the stat mux) on the .2 channel is not
set up correctly.

.         There is something wrong with the PID/PMT table in the encoder for
the .2 channel

 

-gary