According to wikipedia,
16:9 SD video formats are also valid BD-Video formats
https://en.wikipedia.org/wiki/Blu-ray#Video
SD
720 × 480 29.97i 4:3 or 16:9[d] (anamorhic)
720 × 576 25i
4:3 or 16:9[d]
The Create BD Format contains 720 x 576/ 25i/p and 720 x 480/
29.97i/p
Please verify if this these are SD 4:3 only?
The wikipedia table lists only SD interlaced as valid SD BD-Video
format
If so, SD 16:9 interlaced are missing, while SD progressive are
invalid?