A method of processing point cloud data in a transmission apparatus, the method comprising: acquiring the point cloud data; encoding geometry information including positions of points in the point cloud data; encoding attribute information including attribute values of points in the point cloud data based on the geometry information; and transmitting the encoded geometry information, the encoded attribute information and signaling information, wherein encoding attribute information comprises: when a maximum difference value between attribute values of neighbor points is equal or greater than a threshold value, generating predictor candidates based on the neighbor points of a point to be encoded, wherein each predictor candidate corresponds to each prediction mode, wherein the each prediction mode is a prediction mode 1, a prediction mode 2 or a prediction mode 3, wherein a predicted attribute value of the point for the prediction mode 1, the prediction mode 2, or the prediction mode 3 is set as an attribute value of one of the neighbor points, wherein a score of the each predictor candidate is obtained based on rate distortion optimization, and wherein a prediction mode corresponding to a predictor candidate that has a smallest score is set for the point, when the maximum difference value between attribute values of the neighbor points is less than the threshold value, setting a prediction mode 0 as a prediction mode for the point, wherein a predicted attribute value of the point for the prediction mode 0 is set as an average attribute value of the neighbor points, quantizing a residual attribute value of the point based on the set prediction mode, and encoding the quantized residual attribute value of the point. acquiring the point cloud data; encoding geometry information including positions of points in the point cloud data; encoding attribute information including attribute values of points in the point cloud data based on the geometry information; and transmitting the encoded geometry information, the encoded attribute information and signaling information, wherein encoding attribute information comprises: when a maximum difference value between attribute values of neighbor points is equal or greater than a threshold value, generating predictor candidates based on the neighbor points of a point to be encoded, wherein each predictor candidate corresponds to each prediction mode, wherein the each prediction mode is a prediction mode 1, a prediction mode 2 or a prediction mode 3, wherein a predicted attribute value of the point for the prediction mode 1, the prediction mode 2, or the prediction mode 3 is set as an attribute value of one of the neighbor points, wherein a score of the each predictor candidate is obtained based on rate distortion optimization, and wherein a prediction mode corresponding to a predictor candidate that has a smallest score is set for the point, when the maximum difference value between attribute values of the neighbor points is less than the threshold value, setting a prediction mode 0 as a prediction mode for the point, wherein a predicted attribute value of the point for the prediction mode 0 is set as an average attribute value of the neighbor points, quantizing a residual attribute value of the point based on the set prediction mode, and encoding the quantized residual attribute value of the point. when a maximum difference value between attribute values of neighbor points is equal or greater than a threshold value, generating predictor candidates based on the neighbor points of a point to be encoded, wherein each predictor candidate corresponds to each prediction mode, wherein the each prediction mode is a prediction mode 1, a prediction mode 2 or a prediction mode 3, wherein a predicted attribute value of the point for the prediction mode 1, the prediction mode 2, or the prediction mode 3 is set as an attribute value of one of the neighbor points, wherein a score of the each predictor candidate is obtained based on rate distortion optimization, and wherein a prediction mode corresponding to a predictor candidate that has a smallest score is set for the point, when the maximum difference value between attribute values of the neighbor points is less than the threshold value, setting a prediction mode 0 as a prediction mode for the point, wherein a predicted attribute value of the point for the prediction mode 0 is set as an average attribute value of the neighbor points, quantizing a residual attribute value of the point based on the set prediction mode, and encoding the quantized residual attribute value of the point.