Saturday, April 5, 2014

What is difference between 4.3 letterbox & pillarbox?

There are 3 types of content:
1. normal 4:3 where the picture fills the screen on a old 4:3 TV
2. letterbox 16:9 where the picture has blackbars top and bottom and looks correct on a 4:3 TV (much of the series on MNet is like this)
3. Anamorphic 16:9 where the picture fills the screen on a old 4:3 TV but the people are strched vertically (look too tall). This is now available for a few movies on MM1 and on BBC World Service

The SD-PVR has three settings 4:3 Letterbox, 4:3 Pillarbox (bad name, should be pan and scan or centre chop) and 16:9. You can cycle through these with Shift-TV Guide button.

This is how the content will look:

4:3 Letterbox:

1. Picture viewed as normal broadcast, fills the screen
2. Picture viewed as broadcast, black bar top and bottom
3. Black bars are added and appears similar to a show broadcast as 2.

4:3 Pillarbox:

1. Picture viewed as normal broadcast, fills the screen
2. Picture viewed as broadcast, black bar top and bottom
3. The edges of the picture are chopped off so the people no longer appear streched and appears similar to a show broadcast as 2.

16:9: This is meant for widescreen TVs

1. Black bars are added to the edges (Pillarboxing) so the people do not look streched horizontally (fat people)
2. Black bars are added to the edges (Pillarboxing) so the picture will have black bars on all 4 sides.
3. Picture fills the screen and the people look correct whick is why people with widescreen TVs want all content sent out like this.

There is a missing setting which will hopefully come out soon, 16:9 no pillarboxing. The proble with the current 16:9 setting is that not everyone likes pillarboxing of 4:3 content (especially letterboxed 16:9 [2] content) and need to switch back to one of the other options when viewing 4:3 content. Many 16:9 TVs have there own pillarboxing and zooming options which allow viewing the letterbox content so it fills the screen etc. so this option would always fill the screen and allow the view to adjust the picture on the TV



The pillarbox effect occurs in widescreen video displays when black bars (mattes or masking) are placed on the sides of the image. It becomes necessary when film or video that was not originally designed for widescreen is shown on a widescreen display, or a narrower widescreen image is displayed within a wider aspect ratio, such as a 1.85:1 image in a 2.35:1 frame. The original material is shrunk and placed in the middle of the widescreen frame.
Some older arcade games that had a tall vertical and short horizontal are displayed in pillar box even on 4:3 televisions. Some early sound films made 1928–1931, such as City Lights, were filmed in an even narrower format to make room for the sound-on-film track on then-standard film stock. These will appear pillarboxed even on 4:3 screens.[1][dead link]
Pillarboxing is the vertical equivalent of letterboxing and is sometimes called reverse letterboxing. Its name is derived from its resemblance to pillar box-style mailboxes used in the UK and the Commonwealth of Nations. The four-direction equivalent is called windowboxing, caused when programming is both letterboxed and pillarboxed.
In order to use the entire screen area of a widescreen display (which is already significantly less than a fullscreen of equal diagonal measurement), and to prevent a reverse screen burn-in on plasma displays, the simplest alternative to pillarboxing is to crop the top and bottom. However, this results in the loss of some of the image within what the producer assumed would be the safe area. This overscan may or may not bother the viewer, but it often cuts-off the channel banner or other on-screen displays. Likewise, the vertical equivalent of pan and scan is called "tilt and scan" or "reverse pan and scan". This moves the cropped "window" up and down, however it is rarely done. A third option is to stretch the video to fill the screen, but this is often considered ugly, as it severely distorts everything on the screen.
Because certain screen resolutions can be used for both fullscreen and widescreen (anamorphic), widescreen signaling (such as the Active Format Descriptor) must be used to tell the display device which to use, or the viewer must set it manually, in order to prevent unnecessary pillarboxing or stretching on widescreen displays. 

Pillarboxing (reversed letterboxing) is the display of an image within a wider image frame by adding lateral mattes (vertical bars at the sides); for example, a 1.33:1 image has lateral mattes when displayed on a 16:9 aspect ratio television screen.
An alternative to pillarboxing is "tilt-and-scan" (reversed pan and scan), horizontally matting the original 1.33:1 television images to the 1.78:1 aspect ratio, which at any given moment crops part of the top and/or bottom of the frame, hence the need for the "tilt" component. A tilt is a camera move in which the camera tilts up or down.

Windowboxing occurs when an image appears centered in a television screen, with blank space on all four sides of the image,[6][7] such as when a widescreen image that has been previously letterboxed to fit 1.33:1 is then pillarboxed to fit 16:9. It is also called "matchbox", "gutterbox", and "postage stamp" display. This occurs on the DVD editions of the Star Trek films on a 4:3 television when the included widescreen documentaries show footage from the original television series. It is also seen in The Crocodile Hunter: Collision Course, which displays widescreen pillarboxing with 1.85:1 scenes in a 2.40:1 frame that is subsequently letterboxed. It is common to see windowboxed commercials on HD television networks, because many commercials are shot in 16:9 but distributed to networks in SD, letterboxed to fit 1.33:1.
Many 1980s 8-bit home computers feature gutterboxing display mode, because the TV screens normally used as monitors at that time tended to distort the image near the border of the screen, to such an extent that text displayed in that area became illegible. Moreover, due to the overscanned nature of television video, the precise edges of the visible area of the screen varied from television set to television set, so characters near the expected border of the active screen area might be behind the bezel or off the edge of the screen. The Commodore 64VIC-20, and Commodore 128 (in 40-column mode) featured coloured gutterboxing of the main text window, while the Atari 8-bit family featured a blue text window with a black border. The original IBM PC CGA display adapter was the same, and the monochrome MDA, the predecessor of the CGA, as well as the later EGA and VGA, also featured gutterboxing; this is also called underscanned video. The Fisher-Price PXL-2000 camcorder of the late 1980s recorded a windowboxed image to compensate partially for low resolution.


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