Adaptive Voice Playout in VOP

• US 20080243495A1
• Filed: 06/10/2008
• Published: 10/02/2008
• Est. Priority Date: 02/21/2001
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: McCree, Alan V., Anandakumar, Krishnasamy, Paksoy, Erdal
• Granted Patent: US 7,577,565 B2
• Time in Patent Office: Days
• US Class Current: 704/214
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm
• CPC Class Codes: G10L 21/04 Time compression or expansion
• CPC Class Codes: G10L 25/93 Discriminating between voiced and unvoiced parts of speech signals G10L25/90 takes precedence

Abstract

Packetized CELP-encoded speech playout with frame truncation during silence and frame expansion method dependent upon voicing classification with voiced frame expansion maintaining phasealignment.

Claims

1. A method for playout of packetized speech, comprising:

(a) expanding an active frame according to a voicing classification for said active speech frame;

(b) deferring truncation of an active speech frame; and

(c) truncating a silence frame.

2. The method of claim 1, wherein:

(a) said packetized speech includes CELP-encoded frames; and

(b) said truncating a silence frame includes truncating an excitation for said silence frame.

3. The method of claim 1 wherein said expanding is performed when a playout delay for a current frame is greater than a playout delay for a prior frame.

4. The method of claim 1 wherein said deferring occurs when a playout is to decrease.

5. The method of claim 1 further comprising truncating said silence frame by a difference between delay and a new playout delay.

6. A method of frame playout expansion, comprising:

(a) classifying a received active frame as one of (i) voiced, (ii) unvoiced, or (iii) transition;

(b) expanding an unvoiced frame by expanding an excitation for said unvoiced frame with a random fixed-codebook vector; and

(c) expanding a voiced frame by a multiple of the pitch of said voiced frame.

7. The method of claim 6, wherein:

(a) said frames are CELP-encoded frames; and

(b) said expanding a voiced frame includes expanding an excitation for said voiced frame by a multiple of the pitch of said voiced frame.

8. A receiver, comprising:

(a) an input for receiving CELP-encoded frames;

(b) a decoder coupled to said input; and

(c) a playout scheduler coupled to said input and configuration to limit adaptation of said frames to expansion when an active frame is a voiced frame;

(d) said decoder performing expansion of a voiced frame in response to said playout scheduler, wherein said voice frame expansion is a multiple of the pitch for said voiced frame; and

(e) said decoder performing truncation of a frame in response to said playout scheduler only when said frame is a silence frame.