blending is bad
the progressive flag is pretty much only used for pulldown in NTSC, in the PAL world when playing on a normal tv (which is the primary setup for DVD) the progressive flag gets ignored and the dvdplayer and the tv happily show you you the movie as if it was interlaced (ie, field followed by field followed by field, etc etc) and noone notices that theres a 50% lack of motion compared with a real interlaced file cause it IS about 4% smoother than it was in the cinema at 24fps
Enf...