Sound Encoding Device And Sound Encoding Method

• US 20080065373A1
• Filed: 10/25/2005
• Published: 03/13/2008
• Est. Priority Date: 10/26/2004
• Status: Active Grant

• Current Assignee: Optis Wireless Technology, LLC (Brevet Capital)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Oshikiri, Masahiro
• Granted Patent: US 8,326,606 B2
• Time in Patent Office: Days
• US Class Current: 704/203
• CPC Class Codes: G10L 19/0212 using orthogonal transformation
• CPC Class Codes: G10L 19/022 Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring

Abstract

A sound encoding device enabling the amount of delay to be kept small and the distortion between frames to be mitigated. In the sound encoding device, a window multiplication part (211) of a long analysis section (21) multiplies a long analysis frame signal of analysis length M1 by an analysis window, the resultant signal multiplied by the analysis window is outputted to an MDCT section (212), and the MDCT section (212) performs MDCT of the input signal to obtain the transform coefficients of the long analysis frame and outputs it to a transform coefficient encoding section (30). The window multiplication part (221) of a short analysis section (22) multiplies a short analysis frame signal of analysis length M2 (M2<M1) by an analysis window and the resultant signal multiplied by the analysis window is outputted to the MDCT section (222). The MDCT section (222) performs MDCT of the input signal to obtain the transform coefficients of the short analysis frame and outputs it to the transform coefficient encoding section (30). A transform coefficient encoding section (30) encodes these transform coefficients and outputs them.

Claims

1. A speech encoding apparatus comprising:

a analysis section that performs MDCT analysis on one frame of a time-domain speech signal by both a long analysis length and a short analysis length to obtain two types of transform coefficients in a frequency domain; and

an encoding section that encodes the two types of transform coefficients.

2. The speech encoding apparatus according to claim 1, wherein the encoding section performs more accurate encoding on the second transform coefficients obtained by the short analysis length than encoding performed on the first transform coefficients obtained by the long analysis length.

3. The speech encoding apparatus according to claim 1, further comprising:

a determination section that determines whether the speech signal is a stationary portion or a non-stationary portion; and

a second analysis section that repeats MDCT analysis on the one frame a plurality of times by the short analysis length when the speech signal is the non-stationary portion.

4. A radio communication mobile station apparatus comprising the speech encoding apparatus according to claim 1.

5. A radio communication base station apparatus comprising the speech encoding apparatus according to claim 1.

6. A speech encoding method comprising the steps of:

performing MDCT analysis on one frame of a time-domain speech signal by both a long analysis length and a short analysis length to obtain two types of transform coefficients in a frequency domain; and

encoding the two types of transform coefficients.