veryoldschool said:
What SD from DirecTV isn't 4:3?
Many 16:9 shows on HD channels are really widescreen SD, and get up-converted by the receiver.
Similarly, some HD programming IS 4:3 and doesn't have pillar bars added to the signal; those bars are created by the receiver. Obviously, some channels (ESPN is the best example) transmits everything in 16:9 and adds pillar bars to all 4:3 content from the studio. This is not the standard, though, and many channels don't.
This vast inconsistancy and lack of a single standard is why there has to be stretch and zoom modes on TVs and receivers, and for many, that choice is a good thing. For others, they are just confused, because they don't understand that not all content on an HD channel is not necessarily HD, or even 16:9. It will get even more interesting when broadcast goes to digital, and many stations turn off their SD feeds. Lots of people with SDTVs will either have to zoom the HD feed using their converter box or deal with tiny, unreadable (on their SDTV) graphics.
5 years from now, most of this will have been sorted out, and nearly everything will be broadcast in 16:9 HD, but during this transition, everyone is doing their own thing, and it's a mess.