bieling@terra.es wrote:
On May 7, 11:39 pm, "William Garber" <willy4...@garberstreet.com> wrote:For those of you, as I, who were having trouble with this, here is a site that really does it a good turn. Have a read. http://www.projectorcentral.com/component.htmFor this to be true : "Once we've got our video information packaged up in component video format we've reduced bandwidth requirements by a factor of 3 to 2." Even though it's not mentioned in the article, going from RGB to YPbPr, the video image has to be chroma-subsampled, somehow "NTSC- izing" it, although to a lesser degree.
Strictly speaking, the chroma signals don't *have* to be bandwidth- reduced, but in the video transmission/recording context for which component video was designed, they always are. This is a consequence of the reduced "chroma" resolution of the human eye. Our sense of "sharpness" comes from the luminance component, and we are broadly tolerant of reduced chroma sharpness. Clearly, computer graphics can lead to very different requirements-- like a narrow font that has the same luminance as its background. -michael NadaNet file server for Apple II computers! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it's seriously underused."