Converting Pixel Aspect Ratios (Mac OS X)

OC Productions · 24th January 2007

Hey guys, im just wondering if anyone knows how to convert pixel aspect ratios for quicktime?
My footage shot in 16:9 seems to appear as 4:3.

Thanks.

DXNMedia · 24th January 2007

This is a very tricky situation because a lot of people do not understand what is the difference in 4:3 vs. 16:9.

There are standard 4:3, 4:3 letterboxed, & 4:3 anamorphic
These are all different ways of displays, and most of the time, the problem lies in the way you display your output.

A true 16:9 footage will display in a 4:3 aspect in a squished mode (4:3 anamorphic).
So technically, when you master it out to a 4:3 aspect, it should be a squished picture.
If you master it out in a 16:9 mode, it will look normal, but with letterboxed on a 4:3 display.

Aspect conversion should be done in a proper way with decidated video processors, but the current trend is to do it the cheap and easy way by rescale. There are proper calculations involved in doing a rescale.

When you convert 16:9 to 4:3 picture, technically u lose picture content & resolution.
When you convert 4:3 to 16:9, you lose horizontal resolution.

DXNMedia · 24th January 2007

by messing with your pixel aspects, you'll be screwing yourself big time if your final mastering is meant for television or broadcast.

shojibake · 24th January 2007

When you say seems to appear as, do you mean it's appears as 4:3 or 4:3 letterbox, or stretched square pixel ratio? For PCs, there are times when the quicktime player displays non square pixels as square pixels. You should output that as a square pixel quicktime file.

jaegersing · 24th January 2007

Originally Posted by OC Productions

Hey guys, im just wondering if anyone knows how to convert pixel aspect ratios for quicktime?
My footage shot in 16:9 seems to appear as 4:3.

Thanks.

Sorry, not familiar with FCP, but in other NLEs you can inspect the Properties of the footage, check that the aspect ratio is being interpreted correctly, and change it if necessary. In Vegas and Edius, you just right-click on the clip which brings up a menu where you can access the Properties. I'd be surprised if FCP did not have something similar.

OC Productions · 25th January 2007

Alright. Very simply put, i had imported all my footage into avi. format while i was back using XP. Now that i've taken the footage to be edited on a mac os, the footage shot in 16:9 displays as 4:3 squished, when the file is played.

Which means that my quicktime displays these rectangular pixels as square pixels right?
What could the problem be then?

Changing pixel aspect ratios was what a friend suggested so i wasn't too sure about it, just wanted to ask

Thanks.

kristian · 3rd February 2007

Go into the Sequence Settings and enable the Anamorphic check box. This will allow you to preview your 16:9 clip in 4:3 letterbox. This is just preview and does not affect the actual video.

If you want to render to a 4:3 letterbox or output that, nest the 16:9 timeline in a normal 4:3 timeline and you're set.

24th January 2007	#1
OC Productions New Member Join Date: Dec 2006 Location: Singapore Posts: 12	Converting Pixel Aspect Ratios (Mac OS X) Hey guys, im just wondering if anyone knows how to convert pixel aspect ratios for quicktime? My footage shot in 16:9 seems to appear as 4:3. Thanks.

24th January 2007	#2
DXNMedia Moderator Join Date: Dec 2006 Location: Singapore Posts: 666	Re: Converting Pixel Aspect Ratios (Mac OS X) This is a very tricky situation because a lot of people do not understand what is the difference in 4:3 vs. 16:9. There are standard 4:3, 4:3 letterboxed, & 4:3 anamorphic These are all different ways of displays, and most of the time, the problem lies in the way you display your output. A true 16:9 footage will display in a 4:3 aspect in a squished mode (4:3 anamorphic). So technically, when you master it out to a 4:3 aspect, it should be a squished picture. If you master it out in a 16:9 mode, it will look normal, but with letterboxed on a 4:3 display. Aspect conversion should be done in a proper way with decidated video processors, but the current trend is to do it the cheap and easy way by rescale. There are proper calculations involved in doing a rescale. When you convert 16:9 to 4:3 picture, technically u lose picture content & resolution. When you convert 4:3 to 16:9, you lose horizontal resolution. __________________ DXNMedia.net Post Production \| Video Acquisition \| Tape Transfers \| Microwave RF Camera Services

24th January 2007	#3
DXNMedia Moderator Join Date: Dec 2006 Location: Singapore Posts: 666	Re: Converting Pixel Aspect Ratios (Mac OS X) by messing with your pixel aspects, you'll be screwing yourself big time if your final mastering is meant for television or broadcast. __________________ DXNMedia.net Post Production \| Video Acquisition \| Tape Transfers \| Microwave RF Camera Services

24th January 2007	#4
shojibake Member Join Date: Dec 2004 Posts: 385	Re: Converting Pixel Aspect Ratios (Mac OS X) When you say seems to appear as, do you mean it's appears as 4:3 or 4:3 letterbox, or stretched square pixel ratio? For PCs, there are times when the quicktime player displays non square pixels as square pixels. You should output that as a square pixel quicktime file.

25th January 2007	#6
OC Productions New Member Join Date: Dec 2006 Location: Singapore Posts: 12	Re: Converting Pixel Aspect Ratios (Mac OS X) Alright. Very simply put, i had imported all my footage into avi. format while i was back using XP. Now that i've taken the footage to be edited on a mac os, the footage shot in 16:9 displays as 4:3 squished, when the file is played. Which means that my quicktime displays these rectangular pixels as square pixels right? What could the problem be then? Changing pixel aspect ratios was what a friend suggested so i wasn't too sure about it, just wanted to ask Thanks.

3rd February 2007	#7
kristian Member Join Date: Apr 2002 Location: Melbourne & Singapore Posts: 70	Re: Converting Pixel Aspect Ratios (Mac OS X) Go into the Sequence Settings and enable the Anamorphic check box. This will allow you to preview your 16:9 clip in 4:3 letterbox. This is just preview and does not affect the actual video. If you want to render to a 4:3 letterbox or output that, nest the 16:9 timeline in a normal 4:3 timeline and you're set.