On Thu, 29 Mar 2001, Ben Bridgwater wrote: > > Trent Piepho wrote: > > > > > > > > The Rec.601 Y'CbCr colorspace used by bt848 is different than that used by the > > > JFIF standard. It would be better to call the colorspace used by jpeg Y'PbPr. > > > If you take the "YUV" data from a bt848 and try to jpeg encode it without > > > modifiying the data, your JPEG will look wrong. Been there, done that, wrote > > > a Y'CbCr -> Y'PbPr converter so my JPEGs would look correct. > > I just checked the color space FAQ: > > http://www.neuro.sfc.keio.ac.jp/~aly/polygon/info/color-space-faq.html Try a newer one, like http://www.landfield.com/faqs/graphics/colorspace-faq/ that faq is from 1994. The colorspace used by JPEG is in section C-28, while that used by the bt848 is in C-29. You're welcome to try it yourself, but you will see that I am correct. You can look at the transformation equations in the libjpeg source and the bt848 manual, and see that they are different.
