Bug fix: PXR24 compression did not work properly for channels with ySampling != 1.
Bug fix: PXR24 compression did not work properly
for channels with ySampling != 1.

oglops/IlmBase,oglops/OpenEXR,oglops/PyIlmBase,oglops/PyIlmBase,oglops/IlmBase,oglops/OpenEXR,oglops/IlmBase,oglops/OpenEXR,oglops/PyIlmBase,oglops/PyIlmBase