Patent ID: 7647221

Claim:
A method of audio level control for compressed audio in a data stream, comprising: (a) extracting, in a processor, scale factors for the compressed audio from the data stream; (b) performing, in the processor, a level detection for the compressed audio by: (1) determining a square of a derived peak analog voltage value for each of the scale factors; (2) performing a square root of a sum of the squares across a frame; (3) normalizing the square root based on a number of channels present in the compressed audio; and (4) comparing the normalized square root against a threshold to determine whether the compressed audio exceeds a specified level; (c) altering, in the processor, only the extracted scale factors, based on the level detection, without decompressing the compressed audio or altering any other portion of the data stream; and (d) updating, in the processor, the data stream with the altered scale factors, wherein the data stream otherwise remains unchanged.