From the BBC:
Widescreen
A widescreen television picture has the same number of vertical lines as a 4:3 picture, that is 576. The aspect ratio is 16:9 making the picture:
(576 x 16) ÷ 9 = 1024 square pixels wide
A widescreen picture "fits" into the same electronic space as a 4:3 image. The 16:9 widescreen (1024 by 576) image is horizontally squeezed to 702 by 576. The picture is distorted to be the correct shape on 16:9 screens only, hence tall thin people when the image is seen on a 4:3 screen. The additional 18 pixels in the 4:3 picture, when stretched to 16:9 become:
(18 x 4) ÷ 3 = 24 non square pixels or 24 x 1.094 = 26 square pixels
When making a 16:9 graphic on a square pixel device for conversion to a 720 by 576 widescreen video picture, the width of the 1024 by 576 image must be increased:
26 +1024 = 1050 by 576 square pixels
http://community.avid.com/cfs-filesystemfile.ashx/__key/CommunityServer.Components.PostAttachments/00.00.54.02.29/BBC-_2D00_-Commissioning-_2D00_-A-Guide-to-Picture-Size.pdf
Posted by: tcurren@aol.com
| Reply via web post | • | Reply to sender | • | Reply to group | • | Start a New Topic | • | Messages in this topic (9) |
No comments:
Post a Comment