(Page 2 of 4 pages for this article  <  1 2 3 4 >)

Monday, February 18, 2008

Non-Square Strategies

Suggested workflows when dealing with non-square pixels and anamorphic formats.

The Maximum Sanity Route

There is just a certain comfort level in working at the aspect ratio which matches how the viewer will eventually see the final image - you don’t need to worry about accidentally compromising your graphic design, font size, and the such as you compensate for looking at non-square pixels.

Therefore, if we’re not worried about shot matching (not that you will be able to tell after the video has been compressed and broadcast), clients who are insane about image quality, or any other essential reason to maintain the look of the original image as accurately as possible, we will then instead set up our compositions, timelines, and the such at the corresponding square pixel size for the format we’re working in.

In the 1080-line HDV case we’ve been talking about, that size would be 1920x1080 square pixels; for widescreen standard definition video, it would be 864x486 for NTSC or 1024x576 for PAL. As long as you have set the PAR correctly for all of your source footage, and remember to set your comp or timeline to use square pixels, your software should automatically expand your sources to fit your full composition or sequence size.

There are a few advantages to going this route:

• You will see the image displayed correctly - with no PAR distortion - on your computer screen without the need for an external display system.
• You do not have to worry about any effects or image processing steps that may not correctly take PAR into account, forgetting to set the PAR switch correctly in programs such as Photoshop, etc.
• Although you will be altering your source footage slightly by scaling its non-square pixels to fit your square-pixel composition, from that point on you will be performing image processing on more pixels - which in a few cases may result in higher quality or more consistent results. For example, if you apply a light ray, lens flare, or star glow effect to the footage, that effect will be generated with the maximum number of pixels - not the reduced size of the original footage.

If you follow this path, there are two things you need to also take into account:

• You’ll suffer a performance hit, as you’re processing more pixels.
• You must make sure you re-scale the image back down to its correct final size when you render. In a program such as After Effects, you can do this in the Output Module in the Stretch section. Check the Stretch option, uncheck the Lock Aspect Ratio switch, then change the width back down to 1440 for HDV or 720 for the SD widescreen examples mentioned above.

In After Effects, you can re-introduce non-square pixels as you save the file to disk by using the Stretch section in the Render Queue’s Output Module for your comp.

Of course, there are exceptions to every rule; in the next page we’ll discuss a few of those exceptions with the Standard Definition (SD) NTSC video formats such as D1 and DV.

Motion Graphics • Post Production • Visual Effects •

(Page 2 of 4 pages for this article  <  1 2 3 4 >)

Tapeless Cinematography Workflow v2

Michael Vitti | 08/06- 06:58 PM

NewBlue and VASST improve AVCHD performance with AVCHD UpShift

Randy Boyes | 06/25- 01:43 PM

mocha AE to CC Power Pin

Chris Meyer | 05/31- 10:08 AM

Review: Sony HVR-Z7 & HVR-S270 1/3” 3-CMOS HDV camcorders

Adam Wilt | 05/21- 12:17 PM

AE Puppet Tool

Richard Harrington | 04/21- 11:03 PM

Name:

Email:

Location:

URL:

Smileys

Remember my personal information

Notify me of follow-up comments?

Submit the word you see below: