void(* intra_pred[4])(struct HEVCContext *s, int x0, int y0, int c_idx)
void(* pred_angular[4])(uint8_t *src, const uint8_t *top, const uint8_t *left, ptrdiff_t stride, int c_idx, int mode)
void(* pred_dc)(uint8_t *src, const uint8_t *top, const uint8_t *left, ptrdiff_t stride, int log2_size, int c_idx)
void(* pred_planar[4])(uint8_t *src, const uint8_t *top, const uint8_t *left, ptrdiff_t stride)