NBC HD sound

[Lak7]

unless they are generating the analog signal from the HD digital,

I think the HD Digital is the only one available, otherwise some place like Lyngsat would have a Analog signal still listed.

 

[B.J.]

I think the HD Digital is the only one available, otherwise some place like Lyngsat would have a Analog signal still listed.

Yeah, but there is still the question of whether the local channel makes their SD analog first, or their SD digital. Ie assuming that they get the HD digital stream off satellite, do they do:

HD-Dig--->analog---> SD-Dig
or
HD-Dig--->SD-Dig--->analog

I think that the big delay in the SD-dig and the fact that I'm seeing the analog before the HD-Dig (which it came from, suggesting that the delay is in my TV) suggests that it must be the first option, otherwise the analog would be delayed.
I guess this surprised me a bit, because I just assumed that it would be easier to create the SD analog from the SD-Dig signal, and I assumed that it would be easier to go from HD--> SD with the digital signal, but that doesn't seem to be the case. I guess that there is also the possibility that both the analog and SD-Dig come from the HD-Dig, ie:

HD-Dig--->analog
AND
HD-Dig--->SD-Dig

but that the process that creates the SD-Dig is much more time consuming? But this doesn't make sense to me, because if you have an analog signal, it sure seems like the A/D conversion would be quicker than 2.5 seconds. I think that's close to what I observe with my TIVOs, and surely they would use something faster than a consumer TIVO.

But anyway, it's interesting to me just where the delays are coming from, and why. Not important, I just like to understand what's happening.