A transmission device of point cloud data and method performed by the transmission device, and a reception device and a method performed by the reception device are provided. A method performed by a reception device of point cloud data comprises acquiring geometry-based point cloud compression (G-PCC) file including the point cloud data, wherein the G-PCC file includes information on a sample group in which samples in the G-PCC file are grouped based on one or more temporal levels and wherein the G-PCC file further includes information on the temporal levels, and extracting one or more samples belonging to a target temporal level from the samples in the G-PCC file based on the information on the sample group and the information on the temporal levels.