It is kinda both, if you can imagine that. The picture looks like it should be wide screen in many cases (ie, nifty black bars on the top and bottom), but the whole thing is stuffed within pillar boxes. So it is kind of like wide screen being mushed, and then shown back on a wide screen, resulting in a horrible black frame all around the channel... I feel like I have a 17" tv while watching that channel (which I only do to look for any sign of hd content).
Then it is NOT stretched. You're describing a letterboxed program on a 4:3 channel...like TCM. And...as I have believed all along...it's just the SD feed upconverted.
Weird...wonder why BET-HD is stretched.