An SBR tool for very lowdelay applications with flexible crossover frequency

In the field of audio coding a technique called Spectral Band Replication (SBR) is used in several codecs to reduce the data rate. We already developed an SBR tool with very little algorithmic delay for use in low delay applications like teleconferencing or live music performance but it produces a relatively high amount of side information. Further it only supports an SBR crossover frequency at half the signal bandwidth. This paper presents an enhanced SBR tool for low delay applications which uses a method known from speech coding called Codebook Mapping (CBM) to get a reduced side information data rate and an optional 3 band decomposition to reach low crossover frequencies. This leads to a low delay SBR tool with a reduced amount of side information and flexible crossover frequencies.