I've spent a couple of hours now drawing lines in pixelmator and encoding them in various ways. I've gathered about 20 samples of various exports so far. I have stopped at this stage because a couple of things have become apparent. Not that I can explain them but I am able to describe them, hopefully someone can make more sense of them than me.
I should point out that I used a test sample produced in pixelmator which consisted of 40 lines of alternating black and white lines of 1 pixel each, under which I placed 16 lines starting with a white one, then 5 sets of red, blue and yellow lines (w/r/b/y/r/b/y... you get the idea). For the avoidance of doubt my sample was 1920 x 1080, but my lines were only in one corner. (I also threw in some black and white and some r/b/y vertical lines).
One observation that helped a little is that the viewer in im09 (could have been the same in im08) shows all the fields in a progressive clip, well let's say it doesn't simply show one field anyway, let's leave it for now that it showed all 56 lines of my sample.
My first observation was that QT didn't display my lines as expected, instead of a clear w/b/w/b pattern the display was blurred and the pattern was more like grey/wh/grey/bl/grey/wh/grey.... for both interlaced and progressive. The colours were just mixed up but different for progressive and interlaced. What's more they were the same for vertical lines.
However the really, really odd thing is that I can't take a screenshot of this, when I do the image is a clear(ish) w/b/w/b.
Add to this that if I then process the progressive video to interlaced and the interlaced to progressive at the same resolutions, it almost seems that QT is processing the source video as g/w/g/b/g/w... rather than w/b/w/b... and I end up with something like b/w/g/g/w/b.
It's as though the displayed video is blended even though the encoded video isn't, but when it's processed to another format it's the displayed (blended) video that gets converted and not the encoded video.
I also wonder about the deinterlacing not working in QT, I'm sort of thinking it might be working, the output is clearly progressive it just seems messed up. Could it be that it is deinterlacing the w/g/b/g/w.... effect and not the w/b/w/b..... but deinterlacing it as though it were deinterlacing the w/b/w/b....
Does that make sense
I've posted some of my results to this page...
http://web.mac.com/gartside1104/ATV/IM09.html
It's a bit messed up at this stage and I haven't fully checked everything I've put down. I got to the stage where there were so many variables to track that, it's become a bigger project than I thought. For now it just has some of my QT exports on it.
Moving on to im09, I've observed that the viewer in im09 (could have been the same in im08) shows all the fields in a progressive clip, well let's say it doesn't simply show one field anyway, let's leave it for now that it showed all 56 lines of my sample Which was quite helpful. Actually I've also found out this depends on what size your viewer is.
Because of this I have also noticed that my sample image in im09 displays differently again in im09. It's not w/b/w/b.... and it's not w/g/b/g/w..... it's distinctly 40 lines of varying shades of black, white and grey.
______________________________________________________________
Steve said
Winston -- does DEINTERLACE work in QT PRO?
I'm tempted to say yes because of what I'm thinking above however I suspect you are asking if exporting 1080i to 720p works in QT and the answer is whether it works or not the export is just the same as exporting 1080i to 720p in im09.
Finally, Just to confirm if I export from im09 at 1080i, and send that output through JES to deinterlace and reduce to 720p to get a perfect result, it doesn't matter at all whether my export from im09 is 1080i clean or 1080i classic. Indeed you can toggle the clean export back to classic in QT and the result is exactly the same as exporting to classic in the first place.
