Where is the right pixel aspect ratio? at DVinfo.net

Natan Pakman · September 9th, 2009, 08:21 AM

I am trying to export 16:9 widescreen dv video, that I believe is 720 x 480, with a pixel aspect ratio of 1.2, to widescreen H.264 and/or Quicktime (without letterboxing, just as the footage was shot). However, in the export settings, whether I select a pixel aspect ratio of 1.2 or 1.0 (or .9, but that is way off), the video is stretched and looks terrible. If I export to MPEG2 with the 720 x 480 (1.2) settings, the video looks fine.

What is going on here?

Shaun Roemich · September 9th, 2009, 09:10 AM

Try 848 x 720, PAR of 1.

Boyd Ostroff · September 9th, 2009, 12:02 PM

848 by 720? Could you elaborate on that?

Natan Pakman · September 9th, 2009, 01:13 PM

I second that. 848 x 720 with a PAR of 1 did not work; it was more distorted.

Boyd Ostroff · September 9th, 2009, 01:53 PM

If you are using h.264 I think you just need to do the math such that the ratio is 16:9. Or at least that's what I have been doing for YouTube and it works fine (I am using 640x360 there, for example). So my vote would be 852x480 with PAR of 1.

My guess is that Shaun made a typo and really meant 848x480.

Natan Pakman · September 10th, 2009, 12:54 PM

Between 848 and 856 x 480 was a PAR of 1 is pretty close.

However, unlike when I export to H.264 from an HDV (MPEG2) source, when I play it back in a windows video player and full screen it, the letterboxing, that is, the black bars themselves, bounce up and down.

When I export in MPEG2, this does no occur; I get rock-solid letterboxing. This is a strange problem, but I'm assuming there is a very specific cause. Any ideas?

Shaun Roemich · September 10th, 2009, 01:25 PM

Quote:

Originally Posted by Boyd Ostroff

My guess is that Shaun made a typo and really meant 848x480.

Yup. My bad.

As well, 848 is divisible by 16 which is a requirement for some MPEG variants so I ALWAYS ensure that MPEG destined media is divisible by 16.

Ervin Farkas · September 17th, 2009, 05:59 AM

Nathan, what is the destination of your H264 video?

Computer playback? TV playback? It makes a difference...

September 9th, 2009, 08:21 AM	#1
Natan Pakman Regular Crew Join Date: Feb 2009 Location: Los Angeles, CA Posts: 196	Where is the right pixel aspect ratio? I am trying to export 16:9 widescreen dv video, that I believe is 720 x 480, with a pixel aspect ratio of 1.2, to widescreen H.264 and/or Quicktime (without letterboxing, just as the footage was shot). However, in the export settings, whether I select a pixel aspect ratio of 1.2 or 1.0 (or .9, but that is way off), the video is stretched and looks terrible. If I export to MPEG2 with the 720 x 480 (1.2) settings, the video looks fine. What is going on here?

September 9th, 2009, 09:10 AM	#2
Shaun Roemich Inner Circle Join Date: Sep 2002 Location: Vancouver, British Columbia (formerly Winnipeg, Manitoba) Canada Posts: 4,088	Try 848 x 720, PAR of 1. __________________ Shaun C. Roemich Road Dog Media - Vancouver, BC - Videographer - Webcaster www.roaddogmedia.ca Blog: http://roaddogmedia.wordpress.com/

September 17th, 2009, 05:59 AM	#8
Ervin Farkas Inner Circle Join Date: Aug 2005 Location: Atlanta/USA Posts: 2,515	Nathan, what is the destination of your H264 video? Computer playback? TV playback? It makes a difference... __________________ Ervin Farkas www.AtlantaLegalVideo.com

September 9th, 2009, 12:02 PM	#3
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	848 by 720? Could you elaborate on that?

September 9th, 2009, 01:13 PM	#4
Natan Pakman Regular Crew Join Date: Feb 2009 Location: Los Angeles, CA Posts: 196	I second that. 848 x 720 with a PAR of 1 did not work; it was more distorted.

September 9th, 2009, 01:53 PM	#5
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	If you are using h.264 I think you just need to do the math such that the ratio is 16:9. Or at least that's what I have been doing for YouTube and it works fine (I am using 640x360 there, for example). So my vote would be 852x480 with PAR of 1. My guess is that Shaun made a typo and really meant 848x480.

September 10th, 2009, 12:54 PM	#6
Natan Pakman Regular Crew Join Date: Feb 2009 Location: Los Angeles, CA Posts: 196	Between 848 and 856 x 480 was a PAR of 1 is pretty close. However, unlike when I export to H.264 from an HDV (MPEG2) source, when I play it back in a windows video player and full screen it, the letterboxing, that is, the black bars themselves, bounce up and down. When I export in MPEG2, this does no occur; I get rock-solid letterboxing. This is a strange problem, but I'm assuming there is a very specific cause. Any ideas?