Hi Nick,
even if someone also did capture the same broadcasting, it doesnt mean that "he" got the same quality finally on his disk.
There are MUCH things which do influate the capt. quality, like Hardwaresetup, CableTVProvider, The quality of the Cable connections in someones house and so on.
ALSO! As recently many Broadcasting stations did change to Digital Broadcasting, it can happen that some Providers do simply take the bad encoded DVB signal which will be inversed again to an analogue signal for beeing broadcasted via regular analogue cable connection.
I have some Musik Video on my disk from the "ONYX" Station and I did capture them via my analogue Cable connection and an analogue TV card. The funny thing was, that some of these Stream do got some "DVB coloured DCT Block distrotions" even I didnt streamed via DVB .... catch the point?