Re: Pixel Aspect Ratio Conversion For Down Convert??

[Jay Lee]

Beg your pardon……..I am referring to this process with in After Effects.

Cheers,

JV

[Kevin Camp]

if the 1080 footage is interlaced make sure ae is correctly separating fields (i know 1080i in ntsc is upper first), i’d also check the option for preserve edges. you can check this info by selecting the footage in the project window the choose file>interpret footage>main).

once everything is all set with the footage, then just drag it onto the make comp icon, choose composition>comp settings and choose a d1 720×486, .9 preset (note if the footage was 24p, you’d want to maintain the 23.976 frame rate). then select the footage layer in the comp and choose layer>transform>fit to comp height to center cut the 16×9 hd footage, or choose layer>transform>fit to comp width to letter box the 16×9 footage.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Jay Lee]

Thank you for taking the time to write Kevin. Most appreciated indeed.
FPS no problem……source material is 24 FPS Progressive.
I am on the right track since I have been using the work flow you describe above however here is where my confusion stems from:
Rendering an SD comp as you describe indeed yields a PAR accurate file. QT plays it distorted which makes sense since it is displaying Square pixels but when I bring this SD file into compressor to convert to H264 the resulting 264 file is distorted as well even though Compressor is interpreting my source as having a PAR of 1.111. Do I need to have Compressor convert back to square pixels for web display? If so how might this be achieved.

Best,

J

[Kevin Camp]

i don’t have compressor here, but i have used it before… i think compressor has the ability to downsize and crop files as part of it’s compression order. so you may be able to do this within compressor, without needing ae to down convert and center cut the hd source… but, i’m no expert on compressor….

my guess is that your trouble is occurring due to compressor not recognizing the .9 pixel aspect ratio of the footage.

since it sounds like you don’t need d1 material for your destination, you might just put your hd footage into a square pixel comp that matches the destination frame size that you need. so if you need your web footage to be say, 640×480, just create a comp (or set the current comp settings to) 640×480, square pixel, 23.976 fps. conform the footage using fit to comp height to center cut the footage, then render and take that to compressor.

if you wanted to maintain the full frame, 16×9 aspect of the hd footage, just work in a 16×9 aspect square pixel frame size that will work for your web content, maybe 864×486. then just fit the footage to comp size, render and take that to compressor.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Jay Lee]

Excellent suggestion Kevin….thank you. A case where simpler is better.

Best,

J