OpenGL extension SGIX.ycrcb
This module customises the behaviour of the
OpenGL.raw.GL.SGIX.ycrcb to provide a more
Overview (from the spec)
This extension provides a method for OpenGL to read and store
images that are defined in standard YCRCB 422 and 444 video formats.
As with the CYMK extension, conversion to RGBA takes place immediately
following the unpack pixel store, and preceding the pack pixel store
operations, and is only available on transfers to and from memory.
The algorithms that convert between YCRCB and RGBA are "black-box"
in nature, and left undefined by the extension.
Two new formats are added, YCRCB_422_SGIX and YCRCB_444_SGIX.
To handle the difference in sampling rate for 422 video, the pixel
storage operations treat YCRCB_422_SGIX as a 2 component format,
where the first component represents chroma, and the second luma.
The chroma component alternates between Cb and Cr values on
a per pixel basis. If the specified image <width> parameter is not
a multiple of 2, then fragments or texels that result from processing
the <width>th column of pixels will have undefined color value.
YCRCB_444_SGIX is defined as a 3 component format representing
the Cb, Y, and Cr values per pixel.
As with the CMYK extension, this extension doesn't preclude the
possiblity of other higher quality conversion methods.
The official definition of this extension is available here:
|EXTENSION_NAME = 'GL_SGIX_ycrcb'|
GL_YCRCB_422_SGIX = GL_YCRCB_422_SGIX
GL_YCRCB_444_SGIX = GL_YCRCB_444_SGIX
__file__ = '/home/mcfletch/pylive/OpenGL/GL/SGIX/ycrcb.pyc'
__name__ = 'OpenGL.GL.SGIX.ycrcb'
__package__ = 'OpenGL.GL.SGIX'