src_elem_at       142 modules/superres/src/opencl/superres_btvl1.cl         const float srcVal = src_elem_at(src, y, src_step, x);
src_elem_at       148 modules/superres/src/opencl/superres_btvl1.cl                 dstVal += c_btvRegWeights[count] * (diffSign1(srcVal, src_elem_at(src, y + m, src_step, x + l))
src_elem_at       149 modules/superres/src/opencl/superres_btvl1.cl                     - diffSign1(src_elem_at(src, y - m, src_step, x - l), srcVal));