The present technology relates to an encoding device and method, a decoding device and method, and a program, which enable improvement of audio quality.A QMF sub-band power calculation unit calculates power of a QMF sub-band signal of a high frequency QMF sub-band among a plurality of the QMF sub-bands constituting an input signal. A high frequency sub-band power calculation unit carries out an operation to weight more a QMF sub-band power having larger power as for a sub-band including a number of the high frequency QMF sub-bands to calculate high frequency sub-band power of the sub-band. The multiplexing circuit multiplexes high frequency encoded data and low frequency encoded data for outputting. The high frequency encoded data is selected based on the high frequency sub-band power and obtained by encoding information used for obtaining a high frequency component of the input signal by estimating, and the low frequency encoded data is obtained by encoding low frequency components of the input signal. The present technology can be applied to encoding devices.