Your point is a fair one and what is an obvious answer depends greatly on what question is asked and also to a degree on timing. For me the key was recognising that:

1) The lossy encoding could be regarded as bugs.

2) the losses are known by the broadcaster and preserved (without further loss in a digital transmission system) to the viewers home.

Once the nature of the problem is described this way the idea does seem obvious (at least to me with a largely Computer Science rather than video encoding background) but that is not how issues are initially presented and redefining the problem is a great deal of the inventive part.

I would still defend this patent's inventiveness but I fully agree that obviousness is quite subjective