A low bit rate (192 kBits per second) transformation coder / decoder system (192 kBits per second) for high quality music applications employs short time domain sample blocks (128 samples / block), so that the signal propagation delay of the system is short enough for real-time hearing feedback to the user. Pairs of analysis / synthesis windows carefully designed are used to achieve sufficient transformation frequency selectivity despite the use of short sample blocks. A synthesis window located in the decoder has characteristics such that the product of its response and that of an analysis window located in the coder produce a composite response adding to form a unit for two blocks of adjacent samples partially overlapping. Adjacent blocks of signal samples in the time domain are partially overlapped, then summed to cancel the effects of the analysis and synthesis windows. We have developed a technique for deriving pairs of suitable analysis / synthesis windows. In said coder, a discrete transformation is used having a function equivalent to the alternative application of a modified discrete cosine transformation and a modified discrete sine transformation according to the alias cancellation technique in the time domain or, in another embodiment, a discrete Fourier transformation, in order to produce transformation coefficients of the frequency domain. The transformation coefficients are non-uniformly quantified by assigning a fixed number of bits and a variable number of bits determined adaptively, based on psychoacoustic masking. We have developed a destination technique for fixed and adaptive bit assignments. The transmission of secondary information relating to