码流源分辨率和不同输出分辨率的效果

该博文整理自Wiki.

1.      Letterboxing (信箱模式):

Letterboxing isthe practice of transferring film shotin a widescreen aspectratio tostandard-width video formatswhile preserving the film's original aspect ratio. The resulting videographicimage has mattes (blackbars) above and below it; these mattes are part of the image (i.e., of eachframe of the video signal). LTBX is the identifying abbreviation forfilms and images so formatted. The term refers to the shape of a letter box, aslot in a wall or door through which mail is delivered, being rectangular andwider than it is high.

From http://en.wikipedia.org/wiki/Letterboxing_(filming)

2.      pillarbox （柱形模式）:

The pillarbox effectoccurs in widescreen video displays whenblack bars (mattes ormasking) are placed on the sides of the image. It becomes necessary when filmor video that was not originally designed for widescreen is shown on awidescreen display, or a narrower widescreen image is displayed within a wider aspect ratio, suchas a 1.85:1 image in a 2.35:1 frame. The original material is shrunk and placedin the middle of the widescreen frame.

From: http://en.wikipedia.org/wiki/Pillarbox

3.      Windowboxing （窗口模式）

Windowboxing (alsocalled either the "postage stamp effect", "gutterboxing",or "matchboxing") in the display of film or video occurs when the aspect ratio ofthe media is such that the letterbox effect and pillarbox effectoccur simultaneously.^[1][2][3] Sometimes,by accident or design, a standard ratio image is presented in the centralportion of a letterbox picture (or vice versa), resulting in a black border allaround. It is generally disliked because it wastes much screen space andreduces the resolution of the original image. It can occur when a 16:9 film isset to 4:3 (letterbox), but then shown on a 16:9 TV or other output device. Itcan also occur in the opposite direction (4:3 to 16:9 to 4:3). Few films havebeen released with this aspect ratio—one example is The CrocodileHunter: Collision Course,which had numerous scenes with Steve & Terri Irwin usingwidescreen pillar boxing.