Referring to "Procedural Elements for Computer Graphics" by David F. Rogers (1985) the ipp headers list the transformation matrix for RGB to XYZ as follows
X = 0.412453 * R + 0.35758 * G + 0.180423 * B
Y = 0.212671 * R + 0.71516 * G + 0.072169 * B
Z = 0.019334 * R + 0.119193* G + 0.950227 * B
This is listed as the transformation matrix from HDTV (Rec. 709) RGB to CIE XYZ.
Wikipedia shows https://en.wikipedia.org/wiki/CIE_1931_color_space another transformation matrix, which is from CIE RGB to CIE XYZ. Clearly, the RGB to XYZ transformation (and vice versa) depends on the ICC profile of the image. This is true for RGB to LUV and RGB to LAB too, as ipp uses RGB to XYZ as part of those transformations.
Can you confirm the above and is there a special reason why the HDTV color space was chosen ? It seems a logical choice for movies, rather than still images. However, the much used sRGB color space was derived (and is nearly identical) to the HDTV color space.
Regards,
Adriaan van Os