Convert depth map to YUV disparity map for use with VSRS.
vsrs/vsrs_disparity depth.png out_disparity.yuv z_near z_far [8/16]
depth.png is a 16 bit depth image, where pixel values are orthogonal distances. z_near and z_far must be set to the minimal/maximal depth values in the region of interest. A YUV file is written to out_disparity.yuv. It is by default 8 bit, but can be set to 16 bit if 16 is put as the last argument.
The output YUV file is a 3 channel YUV240 file, but only the first channel (Luma Y) is filled with depth values. It is padded to twice that size to add empty UV channels, because this is needed by VSRS.
The values for z_near and z_far need to be given to VSRS as LeftNearestDepthValue and LeftFarthestDepthValue (same for Right) in its config file. To use 16 bit disparity maps, VSRS needs to be recompiled with the appropriate flag.
Only depth values z inside [z_near, z_far] will be mapped to disparity values d. Disparity values are discrete integer values. The mapping is non-linear, for depth closer to z_near, the disparity graduation is finer. The smaller z_far - z_near, the higher the detail in the disparity map.
The mapping is d = a + b/z, with a = -255 z_near / (z_far - z_near) and b = 255 z_near z_far / (z_far - z_near). 255 becomes 65535 for 16 bit disparity maps. d is a projected depth values VSRS uses with its projection matrices to do 3D warping.