Pan-Scan versus Letterbox

Question

Pan-Scan versus Letterbox

I am a bit confused about the use of Pan-Scan vs. Letterbox for 16:9 images to be displayed on either a widescreen (16:9) or a standard (4:3) TV set. Pan-Scan is confusing: I would have assumed that using Pan-Scan as the display mode for 16:9 images (this is slideshow I am talking about) would display the center of the image and cut off the sides on a standard 4:3 TV screen, and display normally on a 16:9 widescreen TV. Not so. I set the display mode to Pan-Scan and burned a DVD: on a stadard 4:3 TV both the sides and the top and bottom of the image was cut off. I thought only the sides would be cut. But worse, on a 16:9 widescreen TV, THE SAME THING HAPPENS! The image is cut off at the sides and top and bottom - it appears to be enlarged (like zooming in) somehow, and so the image resolution is horrible: grainy, etc. When letterbox is used, the widescreen image is good, even the title safe border is not even close to the edge, and the image displays quite well on a 4:3 standard TV with the black bars top and bottom. So my question is, when could a Pan-Scan be used? Is it only for a computer monitor? Would I experience the same thing with video? And what does the choice: "Pan-Scan & Letterbox" (the third choice) offer? very confusing.
Barry

Mac G5, Mac OS X (10.4.8)

Posted on Nov 21, 2006 10:58 AM

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Answer 1

Nov 22, 2006 12:14 AM in response to Barry Garsson

Basically forget Pan and Scan for 16:9 - I don't think it's ever worked reliably in DVD-SP (and yes you would expect that a Pan and Scan setting would basically crop the sides). Set anything that you have as 16:9 as 16:9 letterbox. Then it will appear as 16:9 ona widescreen set and as letterboxed on a 4:3 set (always assuming the end user has their tv and DVD palyer set up properly...)

Steve

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Answer 2

Silal

Level 5

6,461 points

Nov 22, 2006 2:20 AM in response to Barry Garsson

BArry:

This information is taken from DVDSP User Manual:

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Using Pan-Scan to Display 16:9 Video
The pan-scan method of displaying 16:9 video on a 4:3 monitor was developed as a compromise between letterbox, which displays all the video content but with black areas at the top and bottom, and the only other alternative: filling the entire 4:3 screen, but cropping some of the content. With pan-scan, you can choose which bits of the 16:9 content to crop, ensuring the action is not lost by displaying the center of the screen only. The pan-scan method can result in sudden jumps from one side of the screen to the other (for example, to follow a conversation’s dialogue), which may make your video look as if edits have been made.

To make pan-scan work, you must have a pan-scan vector, a frame-based value that controls which part of the content to use. Someone watching the video creates the vector, deciding which parts should be seen. This vector must be available when the video is MPEG-encoded. The MPEG encoder included with DVD Studio Pro does not support pan-scan vector information. However, if the information is already part of an MPEG-encoded video stream, created with an encoder that supports the vector information, DVD Studio Pro passes this information along.

Virtually all movies shown on TV have been through the pan-scan process; however, pan-scan vectors are rarely used for movies released on DVD. Instead, a version of the movie is made using the 4:3 pan-scanned source, and is not intended to be played as a 16:9 video on 16:9 monitors. The other side of the disc often contains the true 16:9 version, set to display as letterboxed video on 4:3 monitors.

Important: Do not use pan-scan if your video does not actually support it. If you do, only the center part of the frame will appear.
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Hope it helps!

Alberto

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Answer 3

Nov 22, 2006 4:27 AM in response to Silal

Thanks guys, that's what I thought. You should be writing the FCP5 manuals.
Barry

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