OpenDCX is an open-source C++ library comprising extensions for the OpenEXR library and its deep file format. It adds support for per deep-sample metadata comprising subpixel-masks and surface-type flags, and provides utility functions to manipulate deep pixels with this metadata. It is developed and maintained by DreamWorks Animation for use in rendering and compositing applications typically encountered in feature film production. The technical details of DCX are described in the paper Improved Deep Image Compositing Using Subpixel Masks
Features and Tools
Efficient Storage Requirements - OpenDCX can dramatically improve image quality with only a modest increase in file size. Deep pixel samples are augmented with a sub-pixel mask and flags that are packed into 3 additional channels that tend to compress very efficiently. Sample code is provided to implement render-side sample consolidation for further reduction in file size.
Backwards Compatibility - OpenDCX deep samples can coexist with traditional OpenEXR volumetric deep samples. Although these samples lack the sub-pixel mask and hard surface flags, they will be properly composited / flattened by the OpenDCX algorithms.
Image Manipulation - The OpenDCX toolset includes a DeepTransform class which implements affine image-space transforms of the deep pixel array. In particular, scaling and rotation benefit from the sub-pixel accuracy of the OpenDCX format. This also allows deep images of differing resolutions to be seamlessly combined.
Pixel reconstruction - The sub-pixel detail of OpenDCX is particularly useful in pixel reconstruction. Deep pixel flattening can be performed per sub-pixel, and each sub-pixel's flattened result can be integrated with other sub-pixel results in a pixel filter.