Streaming normalization

• US 7,343,019 B2
• Filed: 07/25/2002
• Issued: 03/11/2008
• Est. Priority Date: 07/25/2001
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Scarr, Christopher A., Dagani, Gabriel, Kridner, Jason, Millikan, Thomas, Hankins, Timothy C.
• Primary Examiner(s): Chin; Vivian
• Assistant Examiner(s): Faulk; Devona E
• Application Number:
  US10/202,755
• Publication Number:
  US 20030059064A1
• Time in Patent Office: 2,056 Days
• Field of Search: 381/107, 381/104, 381/106, 381/108, 700/94, 709/217, 709/231, 709/218, 709/219, 704/278, 704/500
• US Class Current: 381/107
• CPC Class Codes: H03G 3/002 Control of digital or coded signals H03G3/3089 take precedence

Abstract

A normalization for streaming digital audio signals applies a gain factor according to the maximum sample magnitude in a window of samples and compare the gain factor to prior gain factors to adjust the gain factor for the samples in the window of samples. Adaptation of the gain factor with rapid decreases but slow increases avoids saturation but allows quiet passages.

Claims

1. A method of normalization for streaming digital signals, comprising:

(a) inputting a stream of digital signals into a playout buffer;

(b) finding a current normalization gain for a current output digital signal from said playout buffer by the steps of;

(i) finding the maximum digital signal magnitude of the digital signals in a sequence of digital signals in said playout buffer with said sequence including said current output digital signal where said current output digital signal precedes in said stream all other digital signals in said sequence,

(ii) finding a gain factor for said current output digital signal using said maximum digital signal magnitude from (i),

(iii) combining said gain factor from (ii) with a prior normalization gain for a prior output digital signal from said playout buffer when said gain factor is greater than said prior normalization gain, where said prior output digital signal precedes said current output digital signal in said stream;

(c) outputting said current output digital signal from said playout buffer and modifying said current output digital signal with said normalization;

(d) repeating steps (b) and (c) for a digital signal following said current output digital signal in said stream.

2. The method of claim 1, wherein:

(a) periodically repeating said step (a) of claim 1.

3. The method of claim 1, wherein:

(a) said combining of substep (iii) of step (b) of claim 1 is forming a piecewise linear combination of said prior normalization gain and said gain factor.