The number of bits per block. For simple pixel formats, this value is the same as the traditional bits-per-pixel value. This key is mandatory in pixel format descriptions. See the description for kCVPixelFormatBlockWidth for examples of bits-per-block values.
Available in Mac OS X v10.4 and later.
Declaration Syntax Version Information- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)