The present disclosure relates to a decoding device, a decoding method, an encoding device, and an encoding method, which are capable of enabling a decoding side to accurately recognize a color gamut of an encoding target image. The decoding device includes circuitry configured to receive an encoded stream including encoded data of an image and color primary information indicating a coordinate of at least one color primary of the image. The circuitry extracts the encoded data and the color primary information from the received encoded stream. The circuitry decodes the encoded data to generate the image. Further, the circuitry adjusts a color space of the generated image based on the extracted color primary information. The present disclosure can be applied to, for example, a decoding device of a high efficiency video coding (HEVC) scheme.