Packet converting apparatus and method therefor

• US 7,142,559 B2
• Filed: 10/01/2001
• Issued: 11/28/2006
• Est. Priority Date: 07/23/2001
• Status: Expired due to Fees

• Current Assignee: Ericsson-LG Enterprise Co., Ltd (Telefonaktiebolaget LM Ericsson)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kang, Tae Ik, Choi, Yong Soo
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Ahmed, Salman
• Application Number:
  US09/968,071
• Publication Number:
  US 20020196762A1
• Time in Patent Office: 1,884 Days
• Field of Search: 370/338, 370/229, 704/202, 704207-208, 704/219, 704/230
• US Class Current: 370/466
• CPC Class Codes: G10L 19/00 Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis in musical instruments G10H

Abstract

A packet converting apparatus and method is disclosed, in which audio packet data of various types used in cable/radio networks can effectively be converted. The packet converting apparatus includes a bit unpacking unit for bit unpacking first type packet data, a parameter inverse quantization unit for inverse quantizing the unpacked data to obtain a main parameter of the first type packet data, a parameter converter for converting the obtained main parameter to a parameter of second type packet data through inter-frame interpolation, a quantization unit for quantizing the second type parameter converted by the parameter converter, and a bit packing unit for bit packing the quantized data to reassemble the bit packed data to second type packet data and output the second type packet data to a destination.

Claims

1. A packet converting apparatus for converting a first type packet data to a second type packet data, the packet converting apparatus comprising:

a bit unpacking unit for bit unpacking the first type packet data;

a parameter inverse quantization unit for inverse quantizing unpacked data to obtain a first parameter of the first type packet data, wherein the first parameter includes at least one of line spectrum pair, pitch, adaptive codebook (ACB) gain, ACB index, fixed codebook (FCB) gain and FCB index;

a parameter converter for converting the first parameter to a second parameter of the second type packet data using inter-frame interpolation without synthesizing a pulse code modulation (PCM) signal, wherein the inter-frame interpolation in the parameter converter constrains a search range in response to the ACB gain and the ACB index and searches the search range to obtain values corresponding to the ACB gain and the ACB index of the first parameter and converts the values into an ACB gain and an ACB index of the second parameter;

a quantization unit for quantizing the second parameter converted by the parameter converter and outputting a second type quantized data; and

a bit packing unit for bit packing the second type quantized data to the second type packet data.

2. The packet converting apparatus of claim 1, further comprising a packet conversion determining unit for detecting a destination packet type of the first type packet data and determining that the first type packet data is converted to the second type packet data.

3. The packet converting apparatus of claim 1, wherein the first type packet data is at least one of audio packet data, video packet data, and audio/video packet data.

4. The packet converting apparatus of claim 1, wherein the second type packet data is at least one of audio packet data, video packet data, and audio/video packet data.

5. The packet converting apparatus of claim 1, wherein the inter-frame interpolation in the parameter converter smoothes and scales the line spectrum pair of the first parameter to obtain a line spectrum pair of the second parameter.

6. The packet converting apparatus of claim 1, wherein the inter-frame interpolation in the parameter converter smoothes the pitch of the first parameter to obtain a pitch of the second parameter.

7. The packet converting apparatus of claim 1, wherein the inter-frame interpolation in the parameter converter searches to obtain values corresponding to the FCB gain and the FCB index of the first parameter and converts the values into an FCB gain and an FCB index of the second parameter.

8. A media gateway for communicating between a first communication network using a first type packet data and a second communication network using a second type packet data, the media gateway comprising:

at least one transcoder connected between the first and the second communication network, each transcoder comprising;

a parameter converter for converting a first parameter of the first type packet data to a second parameter of the second type packet data using inter-frame interpolation without synthesizing a pulse code modulation (PCM) signal, wherein the first and the second parameters include at least one of line spectrum pair, pitch, adaptive codebook (ACB) gain, ACB index, fixed codebook (FCB) gain and FCB index, and wherein the inter-frame interpolation in the parameter converter constrains a search range in response to the ACB gain and the ACB index and searches the search range to obtain values corresponding to the ACB gain and the ACB index of the first parameter and converts the values into an ACB gain and an ACB index of the second parameter.

9. The media gateway of claim 8, wherein the transcoder further comprises:

a bit unpacking unit for bit unpacking the first type packet data;

a parameter inverse quantization unit for inverse quantizing unpacked data to obtain a first parameter of the first type packet data;

a quantization unit for quantizing the second parameter converted by the parameter converter and outputting a second type quantized data; and

a bit packing unit for bit packing the second type quantized data to the second type packet data.

10. The media gateway of claim 8, wherein the inter-frame interpolation in the parameter converter smoothes and scales the line spectrum pair of the first parameter to obtain a line spectrum pair of the second parameter.

11. The media gateway of claim 8, wherein the inter-frame interpolation in the parameter converter smoothes the pitch of the first parameter to obtain a pitch of the second parameter.

12. The media gateway of claim 8, wherein the inter-frame interpolation in the parameter converter searches to obtain values corresponding to the FCB gain and the FCB index of the first parameter and converts the values into an FCB gain and an FCB index of the second parameter.

13. A method for converting a first type packet data to a second type packet data, comprising the steps of:

bit unpacking the first type packet data;

inverse quantizing unpacked data to obtain a first parameter of the first type packet data, wherein the first parameter includes at least one of a line spectrum pair, pitch, adaptive codebook (ACB) gain, ACB index, fixed codebook (FCB) gain and FCB index;

converting the first parameter to a second parameter of the second type packet data using inter-frame interpolation without synthesizing a pulse code modulation (PCM) signal, wherein inter-frame interpolation includes constraining a search range in response to the ACB gain and the ACB index and searching the search range to obtain values corresponding to the ACB gain and the ACB index of the first parameter and converting the values into an ACB gain and an ACB index of the second parameter;

quantizing the second parameter and outputting a second type quantized data; and

bit packing the second type quantized data to the second type packet data.

14. The method of claim 13, wherein the first type packet data is at least one of audio packet data, video packet data, and audio/video packet data.

15. The method of claim 13, wherein the second type packet data is at least one of audio packet data, video packet data, and audio/video packet data.

16. The method of claim 13, wherein the step of inter-frame interpolation includes smoothing and scaling the line spectrum pair of the first parameter to obtain a line spectrum pair of the second parameter.

17. The method of claim 13, wherein the step of inter-frame interpolation includes smoothing the pitch of the first parameter to obtain a pitch of the second parameter.

18. The method of claim 13, wherein the step of inter-frame interpolation includes searching to obtain values corresponding to the FCB gain and the FCB index of the first parameter and converting the values into an FCB gain and an FCB index of the second parameter.