Patent ID: 7574355

Claim:
An apparatus for determining a quantizer step size for quantizing a signal comprising audio or video information, the apparatus comprising: a provider for providing a first quantizer step size and an interference threshold; wherein the provider is configured to calculate the first quantizer step size in accordance with the following equation: ∑ i ⁢  Δ ⁢ ⁢ x i  2 ≈ q 2 ⁢ α 12 ⁢ α 2 · ∑ i ⁢ x i 2 ⁢ ( 1 - α ) ; a determiner for determining a first interference introduced by the first quantizer step size; a comparator for comparing the interference introduced by the first quantizer step size with the interference threshold; a selector for selecting a second quantizer step size which is larger than the first quantizer step size if the first interference introduced exceeds the interference threshold; a determiner for determining a second interference introduced by the second quantizer step size; a comparator for comparing the second interference introduced with the interference threshold or the first interference introduced; and a quantizer for quantizing the signal comprising audio or video information with the second quantizer step size if the second interference introduced is smaller than the first interference introduced or is smaller than the interference threshold so that a quantized signal comprising audio or video information is obtained, wherein the quantizer is configured to quantize in accordance with the following equation: y i = round ⁡ [ ( x i q ) α + s ] wherein x i is a spectral value to be quantized, wherein q represents a quantizer step size information, wherein s is a figure differing from or equaling zero, wherein a is an exponent different from “1”, wherein round is a rounding function which maps a value from a first, larger range of values to a value within a second, smaller range of values, wherein is the permitted interference, ∑ i ⁢  Δ ⁢ ⁢ x i  2 and wherein i is a run index for spectral values in the frequency band.