NTSC downres aspect ratio problem

DaVinci Resolve

NTSC downres aspect ratio problem

Posted by Justin Lovell on September 21, 2012 at 10:49 pm

Hey,

Problem rendering a NTSC file.

STEPS:
I have a HD 1920×1080 square pixel file.
I set my output to NTSC
Render my file
Rendered QT file shows more image left and right than it showed in the preview window in resolve. It also has small bars on the top / bottom of the frame. (1/4 the size of a normal letterbox)

WHEN WORKING IN AFTER EFFECTS:
If I take a resolve HD 1920 file and render the NTSC version in AE at 0.9 DV NTSC settings, the image fills the full frame no bars at top/bottom.

Supposing the problem has something to do with the pixel aspect ratio, but unsure.

Can anyone explain how to fix this, or if it is resolve missing a setting?

Thank you,

Justin Lovell /Assoc. CSC
cinematographer//
8/16mm>2K.transfers
http://www.framediscreet.com

Dmitry Kitsov replied 13 years, 7 months ago 3 Members · 5 Replies
5 Replies

William Edwards
September 23, 2012 at 5:02 am

I’m a little confused as to why you would export a 1920×1080 file as ‘NTSC.’ Wouldn’t you simply export a 1920×1080 file? If you are changing the pixel dimensions from an HD square pixel video to a rectangular NTSC file like 720×486, that may account for the error. Also HDV, DVCPRO HD, etc is rectangular.

What is the source file type, and what do you want to get at the end.

The only different in HD from PAL and NTSC is the frame rate.

Also, 864 X 486 is the square pixel equivalent for widescreen NTSC, if that helps.
Justin Lovell
September 23, 2012 at 12:27 pm

I am doing an hd to sd down convert. Client wants an sd file as well as a dvd version.

Justin Lovell /Assoc. CSC
cinematographer//
8/16mm>2K.transfers
http://www.framediscreet.com
William Edwards
September 23, 2012 at 1:09 pm

I would export out of Davinci the full 1920×1080. Then create a letterboxed or center-cut version in another software application.
Justin Lovell
September 23, 2012 at 2:08 pm

yes, that’s what my current workflow is.

Resolve > HD 1920×1080 Prores
After Effects > SD Mpeg-2 (much slower to render than resolve’s HD)
Encore > SD DVD

Would love to eliminate the middle man (AE). Encore’s transcoding is faster, but doesn’t do a centre crop, only a rescale with letterbox bars.

Justin Lovell /Assoc. CSC
cinematographer//
8/16mm>2K.transfers
http://www.framediscreet.com
Dmitry Kitsov
September 23, 2012 at 6:29 pm

In encore enable Transcode using the Media Encoder, then define quality presets and chose settings that will fit your workflow.

Reply to this Discussion! Login or Sign Up

Creative Communities of the World Forums