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Video aspect ratio distortion
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C44
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O.P. Video aspect ratio distortion
I notice my video as well as the video I receive from others is compressed horizontally.  I measured the native output of my webcam and the AR is 1.33 but the video picture sent and received by Messenger is 352 x 288 pixels which results in an AR of 1.22.  Why is this and how can it be corrected? 
07-07-2010 01:03 AM
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matty
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RE: Video aspect ratio distortion
Best thing to do is to discuss this with Microsoft. We have no control over any of this.
07-07-2010 12:55 PM
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djdannyp
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RE: Video aspect ratio distortion
If you go into Audio/Video Setup Wizard, are there any "Advanced options" you can configure on your webcam?  It may well be able to be changed from that
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07-07-2010 01:12 PM
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C44
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O.P. RE: Video aspect ratio distortion
In the video setup the image appears with a correct aspect ratio of 1.33.  It is in the transmission where it gets distorted.

I believe the 352 x 288 pixel picture is determined by the codec used. I seem to remember NetMeeting used the same resolution and had this same defect. 

I believe this is a defect of Messenger and not of the webcam. I believe any webcam with an aspect ratio of 4:3 (which is pretty much all the ones I have ever seen) will have this problem with Live Messenger.

In other words, I believe most people are having this issue but they just don't notice or don't care.  I suppose many will prefer appearing more slender :)


The Common Interchange Format (CIF) Video standards, known as H.261 and H.263, were developed by the International Telecommunications Union.

CIF NTSC resolution: 352 x 240
CIF PAL resolution: 352 x 288

So it seems the video stream is sent with a different aspect ratio and the receiver should stretch or compress horizontally to restore the correct aspect ratio.


  http://en.wikipedia.org/wiki/Common_Intermediate_Format

xCIF pixels are not square, instead having a native aspect ratio of ~1.222:1. On older television systems, a pixel aspect ratio of 1.2:1 was the standard for 525-line systems (see CCIR 601). On square-pixel displays (computer screens, many modern televisions) xCIF rasters should be rescaled horizontally by ~109% to 4:3 in order to avoid a "stretched" look: CIF content expanded horizontally by ~109% results in a 4:3 raster of 384 × 288 square pixels.

So it seems the answer is that the Live Messenger receiver should expand the video horizontally but it is not doing it.

This post was edited on 07-07-2010 at 02:44 PM by C44.
07-07-2010 01:44 PM
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