The present technology relates to an audio signal processing device and method, an encoding device and method, and a program, which are capable of obtaining a higher quality sound. A selection unit selects, from supplied multichannel audio signals, audio signals of a channel of a dialogue sound and audio signals of a channel to be downmixed. A downmixing unit downmixes the audio signals of the channel to be downmixed. An addition unit adds the audio signals of the channel of a dialogue sound to audio signals of a predetermined channel among audio signals of one or more channels obtained in the downmixing. The present technology can be applied to a decoder.