PULSE ALLOCATING METHOD IN VOICE CODING

• US 20090043572A1
• Filed: 02/09/2006
• Published: 02/12/2009
• Est. Priority Date: 02/10/2005
• Status: Active Grant

• Current Assignee: III Holdings 12, LLC (Intellectual Ventures LLC)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yoshida, Koji, Goto, Michiyo, Neo, Sua Hong, Teo, Chun Woei
• Granted Patent: US 8,024,187 B2
• Time in Patent Office: Days
• US Class Current: 704/223
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 19/10 the excitation function being a multipulse excitation

Abstract

A pulse allocating method capable of coding stereophonic voice signals efficiently. In the fixed code note retrievals (ST21 to ST25) of this pulse allocating method, for individual subframes, the stereophonic voice signals are compared (ST21) to judge similarity between channels, and are judged (ST22) on their characteristics. On the basis of the similarity between the channels and the characteristics of the stereophonic signals, the pulse numbers to be allocated to the individual channels are determined (ST23). Pulse retrievals are executed (ST24) to determine the pulse positions for the individual channels, so that the pulses determined at ST24 are coded (ST25).

Claims

1. A pulse apportionment method in a fixed codebook search in speech coding for a stereo signal, comprising determining the number of pulses apportioned to channels of the stereo signal according to characteristics of the channels and similarity between the channels.

2. The pulse apportionment method according to claim 1, wherein, when the similarity is equal to or larger than a threshold value, all pulses are apportioned to one of the channels.

3. The pulse apportionment method according to claim 1, wherein the characteristics are determined based on at least one of a degree of stationarity, periodicity and maximum autocorrelation factor of each channel.

4. The pulse apportionment method according to claim 3, wherein fewer pulses are apportioned to a channel having a larger degree of stationarity, periodicity and maximum autocorrelation factor.

5. The pulse apportionment method according to claim 1, wherein, when the characteristics of the channels are identical, an equal number of pulses is apportioned to each channel.

6. The pulse apportionment method according to claim 1, wherein a codeword indicating the number of pulses apportioned to each channel is reported to the speech decoding side.