An audio coding system in which a plurality of quantization methods are selectable for application to components of a streamed audio signal to achieve a target frame size that is determined by comparing an achieved bit rate against a target bit rate. Based on the target frame size, the system calculates a bit allocation for signal components and compares the bit allocation to the dynamic range of the signal components. Depending on the outcome of the comparison, the system may select to quantize or not quantize a signal component. The system employs lossless coding techniques, but is capable of introducing lossy coding by quantization in order to meet the target bit rate.