The present technique relates to an encoding device and a method, a decoding device and a method, and a program capable of obtaining higher quality audio. An encoding unit encodes position information and a gain of an object in a current frame in multiple encoding modes. A compressing unit generates, for each combination of encoding modes of each pieces of position information and gains, encoded meta data including encoding mode information indicating the encoding modes and encoded data which are the encoded position information and gains, and compresses the encoding mode information included in the encoding meta data. A determining unit selects encoded meta data of which amount of data is the least from among the encoded meta data generated for each combination, thus determining the encoding mode of each pieces of position information and gains. The present technique can be applied to an encoder and a decoder.