Forgive my ignorance, but is what you describe because in HD the fields are of the same moment in time? In SD, I am pretty sure you get aliasing with incorrect field order. In SD, there is a measurable delay between field 1 and 2. Of course, I could be completely off the charts wrong about this.
On Monday, November 9, 2015, David Ross speckydave@gmail.com [Avid-L2] <Avid-L2@yahoogroups.com> wrote:
Just tested this on a broadcast monitor by adding a big diagonal line across some upper-field HD footage. Exported as QuickTime ProRes upper-field, which I them imported into Premiere and played back: smooth motion and no aliasing while interpreted as upper-field. When I switched the interpretation to lower-field, I got all the horrible shuddering from fields being played in the wrong order, but the static diagonal line showed no aliasing at all.I would say your assumption about fields being re-positioned is wrong. When someone mis-interprets upper-field-first footage as lower-field-first, they just get the fields played in the wrong order. That's it. No re-positioning. Just (in this case) the lower field played first, then the upper field.
I would have thought that to take the upper field and shift it down a line to the lower field position and vice versa would be quite a deliberate process. I can't right now think of a way to *accidentally* tell the system to actually reposition the fields like this (though since there generally tends to be a way to easily screw anything up, I don't doubt that it can be done with a single bad keystroke...).D.On 9 November 2015 at 01:24, bigfish@pacbell.net [Avid-L2] <Avid-L2@yahoogroups.com> wrote:If the fields are in reverse order then they are not playing in the same field the are intended for. Think of a diagonal line. I am assuming that with wrong field order Field 2 plays first and is positioned on the lines intended for Field 1 and Field 1 plays second in the lines intended for Field 2. That would mean the horizontal scan lines are inverted too. To me that would create the stair stepping even on a static frame.
Posted by: John Pale <pale.edit@gmail.com>
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