OK, think I may have had a minor revelation. ST:TNG is on at 11am and ST:TOS is on at 12 noon. I have padding set to 2 minutes before, 5 minutes after. ST:TNG records 62 minutes. ST:TOS records 65 minutes. So it cuts off the recording of ST:TNG bang on time, and starts recording ST:TOS - but more often than not, ST:TOS has already started by then
.
I've checked a number ST:TOS recordings which have the start missing and in every case I found the missing start of the ST:TOS programme at the end of the preceding ST:TNG. This is the opposite of what I have occasionally experienced in the past: that you sometimes have to watch the start of the
following recording to get the end of the
previous one. So it's still CBS' fault because they seem regularly to start the following programme early (perhaps to accommodate the overrun suggested by EEPhil).
It does, though, highlight the fact that the Humax doesn't seem to use its tuners intelligently when recording two consecutive programmes on the same channel. If the second tuner isn't being used, why can't it apply the full padding to both recordings ie start recording the second programme from the second tuner, if the recording for the first programme is still in progress?
CBS' timing issues just exacerbate the problem, because if you just want to watch the following programme from the beginning, you have to FFWD or skip through to nearly the end of the recording of the previous programme. Not too much of a pain if they're consecutive episodes of the same series, but in this case they're not, so it is particularly inconvenient. It's a bit disruptive to have to fire up the following recording to see the end of the previous programme, but at least it's not too time consuming. Having to start from the back, as it were, is tedious in the extreme.
I reckon that CBS are using common US broadcasting practice, where one programme starts immediately after another with no or minimal commercial break. This avoids reminding the punter on the sofa that the thing they were watching has actually finished, and thus reduces channel-hopping. You then get an extended ad break
after the teaser - and usually
before the opening credits - by which time the couch potato will hopefully be hooked enough to want to find out what happens next.
Overall conclusion: grrr!