Patent ID: 7640157

Claim:
A method for quantizing an audio signal in an audio coder, the method comprising: partitioning an audio signal into a sequence of successive frames; initializing a quantization step size for each scale factor band of a current frame in the audio signal; quantizing each scale factor band of the current frame with the initialized quantization step size; determining quantized scale factor bands that are at a vanishing point, wherein the vanishing point is a point where at least the peak value of a spectral coefficient among spectral coefficients in each quantized scale factor band remains non-zero; freezing the quantization step size for the determined scale factor bands that are at the vanishing point; comparing the number of bits consumed in coding spectral lines in all scale factor bands in the current frame at the quantization step size to a specified bit rate; if the number of bits consumed is greater than the specified bit-rate, incrementing the quantization step size for quantizing scale factor bands of the current frame that are not at the vanishing point and repeating the steps of quantizing, determining, freezing, and comparing wherein a maximum value of the incremented quantization step size for quantizing a scale factor band is the value beyond which the peak spectral coefficient value among the spectral coefficients in that scale factor band becomes zero; and if the number of bits consumed is not greater than the specified bit rate, exiting the quantization loop for the current frame.