[Jacob Ventura] “HPX170 and using the letterbox 720PN mode”
?? there is no such thing, 720p is only 16:9 square, do you mean 480 (there is no pN in SD).
Letterbox is a 4:3 image with the video scaled to fit. If you shoot SD as Squeeze you will have a full frame widescreen image. But that must be interrupted correcting by the display. A BetaSP does not know what is full WS vs Letterboxed. This is something that a DVD player can do but almost all SD broadcast is letterboxed.
By I would always shoot squeezed because you have normally letterbox when printing to tape without a loss in quality but if you want a 16:9 DVD you have to enlarge the letterbox it get rid of the bars.