Instead of taking frame from ProcessData function call (that has only Luma data), you can use pFrame that is given to AlgLink_ScdAlgCopyFrame() function.
AlgLink_ScdAlgCopyFrame() function get the whole YUV frame that comes to DSP Link and copies only Luma data for DMVAL algorithm.
In this function use below Ptr to get Luma and Chroma data.
pFrame->addr[0][0] -> Luma Data
pFrame->addr[0][1] -> Chroma Data