[kayfox]

So, I just spent the last two months working out the details of how to put a digital cable channel on a hotel cable headend. I have some clarification of what may be going on here.

Cable headends tend not to have very much compression equipment, sometimes they have stuff used for feeds local to the headend, but usually the compression happens at the originating facility. For something like CNN, this is at their studio. The signal with that original compression is encrypted, uplinked to the satellite and then received off the satellite by receivers at the headend. It comes out of that receiver as a compressed digital signal called ASI, which is MPEG2 compressed video over SDI. It is then typically fed into a demultiplexer/multiplexer that will combine or separate it into different streams and then it is fed into a QAM modulator. For ATSC the same is fed into a 8vsb modulator (or something like that). For encrypted systems it is fed into a encryption unit before being fed into the QAM modulator. The key here is that each video stream is not recompressed even when it is remultiplexed.

The issue may be that of signal strengths and associated error rates and how that is reflected in encrypted streams. Typically encryption cases degradation to be reflected poorly in the signal compared to unencrypted signals.