YUV and YCbCr irrelevant
Posted Mar 5, 2010 10:02 UTC (Fri) by farnz
In reply to: YUV and YCbCr irrelevant
Parent article: SCALE 8x: Color management for everyone
Depends on how you define a colour space; on the one hand, they are just a reversible transform from a known RGB colour space. On the other hand, practical YUV colour spaces, while sharing primaries with practical RGB colour spaces, tend to have different gamuts.
Additionally, they only correspond perfectly under the assumption of infinite precision; in colour management situations, it's of interest to the output driver to know that when I ask for 8-bit BT601 RGB (236, 250, 255), it actually came from YUV (230, 140, 120), and thus if display RGB (237, 251, 255) corresponds to BT601 RGB (237, 251, 255) while display RGB (236, 250, 255) corresponds to BT601 RGB (235, 249, 255), the former is a closer approximation to the desired colour than the latter.
YUV colour spaces differ from JPEG in a very important manner; JPEG is lossy by design, whereas YUV isn't lossy until you subsample. Any loss between an RGB and YUV colour space occurs due to loss of precision
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