Systems and methods for encoding and decoding speech for lossy transmission networks

• US 7,554,969 B2
• Filed: 04/15/2002
• Issued: 06/30/2009
• Est. Priority Date: 05/06/1997
• Status: Expired due to Term

• Current Assignee: Audiocodes Limited
• Original Assignee: Audiocodes Limited
• Inventors: Bialik, Leon
• Primary Examiner(s): Nguyen; Brian D
• Application Number:
  US10/122,076
• Publication Number:
  US 20020159472A1
• Time in Patent Office: 2,633 Days
• Field of Search: 370/442, 370/389, 370/352, 370/229, 370/252, 370/392, 370/470, 370/471, 370/474, 704/207, 704/208, 704/214, 704/220, 704/221, 704/230, 704/223, 704/205, 704/227, 704/216
• US Class Current: 370/352
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm

Abstract

A voice encoder which utilizes future data, such as the lookahead data typically available for linear predictive coding (LPC), to partially encode a future packet and to send the partial encoding as part of the current packet. A decoder utilizes the partial encoding of the previous packet to decode the current packet if the latter did not arrive properly.

Claims

1. A voice encoder comprising:

an encoder for partially encoding future data into partially encoded future data, and for encoding a current frame into an encoded current frame; and

a packet creator for creating a packet from said encoded current frame and said partially encoded future data,

wherein said encoder comprises a pitch change processor for determining a pitch in said future data as a change over a current pitch of said current frame, and

wherein said pitch change processor comprises a voiced/unvoiced state determiner for determining a voice/unvoiced state based on the quality of the pitch change determination.

2. A method for encoding voice signals, the method comprising:

dividing a voice signal into fames;

encoding a first frame of said divided voice signal;

partially encoding a second frame of said divided voice signal, said second frame being subsequent in time to said first frame; and

creating a packet comprising said encoded first frame and said partially encoded second frame, wherein said partial encoding of said second frame includes determining a pitch in a section of said second frame as a change over a current pitch of said first frame, and wherein determining comprises determining a voiced/unvoiced state based on the quality of the pitch change determination, and wherein the method is performed by a voice encoder, the voice encoder comprising an encoder and a packet creator.

3. A voice encoder comprising:

an encoder operative to encode a first frame of voice data;

a pitch change processor operative to determine a pitch in lookahead data used for LPC encoding of a second frame of voice data subsequent in time to said first frame, said pitch determined as a change over a pitch of said first frame; and

a packet creator operative to create a packet from the encoded first frame and said pitch in the lookahead data, wherein said pitch change processor comprises a voiced/unvoiced state determiner operative to determine a voice/unvoiced state based on the quality of the pitch change determination.