From FastRawViewer:
What DPRSplit application is for:
Canon 5D Mark IV's sensor has a somewhat unusual pixel arrangement: each pixel is composed of two subpixels. If Dual Pixel RAW mode is enabled in the camera, the resulting CR2 file contains two images, or two frames: one composite, made from reading both subpixels, summed; and the other is made out of one set of subpixels.
The intended use of this arrangement is to enable some extra editing after the shot: because of the parallax between the subpixels, Canon Digital Photo Professional software allows one to perform microadjustment of focus, bokeh shift, and ghosting reduction.
However, there is one more possible use for a dual-pixel raw, which is not covered by the manufacturer: the second frame, the one that is made out of one set of subpixels, collects half of the light that the composite frame does, as if it was exposed one stop lower compared to the composite frame.
In essence, in Dual Pixel Raw mode, the camera records into one file some equivalent of two shots, bracketed by (approximately) 1 EV.
The DPRSplit application allows one to:
Resulting DNG files can then be opened and processed in (practically) any raw converter featuring DNG support.
System Requirements
Download: DPRSplit (Beta 0.8)