WO2009078535A1 - Apparatus and method for generating fixed delay of variable-bandwidth multicodec - Google Patents

Apparatus and method for generating fixed delay of variable-bandwidth multicodec Download PDF

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Publication number
WO2009078535A1
WO2009078535A1 PCT/KR2008/004429 KR2008004429W WO2009078535A1 WO 2009078535 A1 WO2009078535 A1 WO 2009078535A1 KR 2008004429 W KR2008004429 W KR 2008004429W WO 2009078535 A1 WO2009078535 A1 WO 2009078535A1
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WIPO (PCT)
Prior art keywords
time
packets
buffer
compensation
voice
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Application number
PCT/KR2008/004429
Other languages
French (fr)
Inventor
Dae-Ho Kim
Do-Young Kim
Byung-Sun Lee
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Electronics And Telecommunications Research Institute
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Publication of WO2009078535A1 publication Critical patent/WO2009078535A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/66—Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L43/00—Arrangements for monitoring or testing data switching networks
    • H04L43/08—Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters
    • H04L43/0852—Delays
    • H04L43/087—Jitter
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L43/00—Arrangements for monitoring or testing data switching networks
    • H04L43/08—Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters
    • H04L43/0852—Delays
    • H04L43/0858—One way delays
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/60—Network streaming of media packets
    • H04L65/75—Media network packet handling
    • H04L65/752—Media network packet handling adapting media to network capabilities
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/80—Responding to QoS
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/10—Architectures or entities
    • H04L65/1059—End-user terminal functionalities specially adapted for real-time communication

Definitions

  • the present invention relates to a variable-bandwidth multicodec, and more particularly, to an apparatus and method for generating a fixed delay of a variable- bandwidth multicodec by compensating a delay variation of the variable-bandwidth multicodec.
  • Variable-bandwidth multicodecs convert natural sounds into codec data with a plurality of data rates.
  • a variable-bandwidth multicodec classifies frequency bands into a narrow band (300 Hz ⁇ 3,400 Hz), a broad band (50 Hz ⁇ 7,000 Hz) and an audio band (20 Hz ⁇ 20,000 Hz), and calculates codec data with data rates of 8, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 and 32 bps in the respective bands.
  • a network band is variable and unpredictable and a variable-bandwidth multicodec has a 32 bps codec data rate providing the highest voice quality and an 8 bps codec data rate providing the lowest voice quality.
  • VoIP Voice over Internet Protocol
  • a 32 bps transmission band is transmitted using the variable- bandwidth multicodec.
  • a lower transmission band of 30 bps, 28 bps, etc. is transmitted using the variable-bandwidth multicodec so that the network transmission is facilitated while providing low voice quality.
  • variable-bandwidth multicodec When a transmission data rate is high, the variable-bandwidth multicodec can provide high voice quality but has a high probability of causing transmission loss and delay in the network. On the other hand, when the transmission data rate is low, the variable-bandwidth multicodec provides low voice quality but has a low probability of causing transmission loss and delay in the network.
  • an apparatus for generating a fixed delay including: a packet receiver receiving packets; a delay variation detector detecting the minimum time interval between a predetermined number of packets, and calculating, based on the detected minimum time interval, the expected arrival time of a packet received after a predetermined number of the packets; a decoder generating voice data by decoding packets received after a predetermined number of the packets, and storing the generated voice data in a buffer; a delay calculator calculating a delay time of the buffer on the basis of the difference between the expected arrival time and the initial extraction time of the voice data from the buffer, and calculating a compensation time on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer; a compensation voice reproducer reproducing a silent compensation voice during the calculated compensation time; and a voice reproducer reproducing the voice data stored in the buffer after the reproduction of the silent compensation voice.
  • a method for generating a fixed delay including: receiving packets; detecting the minimum time interval between a predetermined number of packets, and calculating, based on the detected minimum time interval, the expected arrival time of a packet received after a predetermined number of the packets; generating voice data by decoding packets received after a predetermined number of the packets, and storing the generated voice data in a buffer; calculating a delay time of the buffer on the basis of the difference between the calculated expected arrival time and the initial extraction time of the voice data from the buffer, and calculating a compensation time on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer; reproducing a silent compensation voice during the calculated compensation time; and reproducing the voice data stored in the buffer after the reproduction of the silent compensation voice.
  • FIG. 1 is a block diagram of an apparatus for generating a fixed delay of a variable- bandwidth multicodec by compensating a delay variation of the variable-bandwidth multicodec according to an embodiment of the present invention
  • FIG. 2 is a flow diagram illustrating a method for generating a fixed delay of a variable-bandwidth multicodec by compensating a delay variation of the variable- bandwidth multicodec according to an embodiment of the present invention. Best Mode
  • an apparatus for generating a fixed delay including: a packet receiver receiving packets; a delay variation detector detecting the minimum time interval between a predetermined number of packets, and calculating, based on the detected minimum time interval, the expected arrival time of a packet received after a predetermined number of the packets; a decoder generating voice data by decoding packets received after a predetermined number of the packets, and storing the generated voice data in a buffer; a delay calculator calculating a delay time of the buffer on the basis of the difference between the expected arrival time and the initial extraction time of the voice data from the buffer, and calculating a compensation time on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer; a compensation voice reproducer reproducing a silent compensation voice during the calculated compensation time; and a voice reproducer reproducing the voice data stored in the buffer after the reproduction of the silent compensation voice.
  • a method for generating a fixed delay including: receiving packets; detecting the minimum time interval between a predetermined number of packets, and calculating, based on the detected minimum time interval, the expected arrival time of a packet received after a predetermined number of the packets; generating voice data by decoding packets received after a predetermined number of the packets, and storing the generated voice data in a buffer; calculating a delay time of the buffer on the basis of the difference between the calculated expected arrival time and the initial extraction time of the voice data from the buffer, and calculating a compensation time on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer; reproducing a silent compensation voice during the calculated compensation time; and reproducing the voice data stored in the buffer after the reproduction of the silent compensation voice.
  • FIG. 1 is a block diagram of an apparatus for generating a fixed delay of a variable- bandwidth multicodec by compensating a delay variation of the variable-bandwidth multicodec according to an embodiment of the present invention.
  • the apparatus according to the present invention includes a packet receiver 100, a delay variation detector 110, a delay calculator 120, a compensation voice reproducer 130, a decoder 140, a reproduction buffer 150, and a voice reproducer 160.
  • the packet receiver 100 receives a voice packet and detects the arrival time of the received voice packet.
  • the received voice packet is generally a user datagram protocol (UDP) packet.
  • the packet receiver 100 transfers a predetermined number of packets, which are received from the initial call start time, to the delay variation detector 110; and transfers packets, which are received after a predetermined number of the packets received from the initial call start time, to the decoder 140.
  • the predetermined number of the received packets transferred to the delay variation detector 110 may vary depending on embodiments of the present invention. In general, the received packets transferred to the delay variation decoder 110 may be about ten packets that do not carry important voice information. The following description will be made on the assumption that the predetermined number of the packets transferred from the packet receiver 100 to the delay variation detector 110 is 'N'.
  • the decoder 140 decodes the (N+ 1)" 1 and following packets, which are received from the packet receiver 100, to generate reproducible voice data.
  • the reproduction buffer 150 stores the voice data generated by the decoder 140.
  • the delay variation detector 110 detects the minimum time interval between the packets on the basis of the arrival times of the N voice packets received from the packet receiver 100. Also, the delay variation detector 110 calculates the expected arrival time of the (N+ 1)" 1 packet on the basis of the detected minimum time interval. For example, if the minimum time interval between the received N packets is T 1n , the expected arrival time T m . of the (N+ 1)" 1 packet is the sum of the minimum time interval Tin and the arrival time of the N" 1 packet.
  • the delay calculator 120 calculates the difference between the extraction time Tout when the voice reproducer 160 extracts the (N+l)" 1 voice data (i.e., the (N+l)" 1 packet) from the reproduction buffer 150 and the expected arrival time Tin' of the (N+ 1)" 1 packet, which is calculated by the delay variation detector 110.
  • the difference between the expected arrival time T m . and the extraction time T out is a packet delay time D buf of the reproduction buffer 150.
  • the present invention aims at generating a fixed delay.
  • the delay calculator 120 calculates the difference (hereinafter referred to as a compensation time) between a predetermined fixed delay time D flx and the delay time D buf of the reproduction buffer 150.
  • the compensation voice reproducer 130 reproduces a compensation voice (i.e., a silent signal) during the compensation time calculated by the delay calculator 120.
  • the data length of the compensation voice reproduced by the compensation voice reproducer 130 is calculated by multiplying the compensation time by the voice data length per unit time.
  • the voice reproducer 160 sequentially reproduces the voice data extracted from the reproduction buffer 150 after the reproduction of the compensation voice by the compensation voice reproducer 130. That is, even though the voice reproducer 160 extracts the (N+ 1)" 1 voice data from the reproduction buffer 150 earlier, the extracted (N+ 1)" 1 voice data is reproduced after the reproduction of the compensation voice during the compensation time calculated by the delay calculator 120.
  • FIG. 2 is a flow diagram illustrating a method for generating a fixed delay of a variable-bandwidth multicodec by compensating a delay variation of the variable- bandwidth multicodec according to an embodiment of the present invention.
  • the present apparatus receives voice packets in operation S200.
  • the present apparatus compensates a predetermined (i.e., N) number of the initial and following received voice packets for a delay variation, uses the compensated voice packets in an operation for generation of a fixed delay, and decodes/reproduces the (N+ 1)" 1 and following packets.
  • N a predetermined number of the initial and following received voice packets for a delay variation
  • the present apparatus determines whether the number of the received packets is smaller than or equal to N. If the number of the received packets is smaller than or equal to N (in operation S210), the present apparatus detects the minimum time interval T 1n between the received packets on the basis of the detected arrival times of the received packets in operation S220. In operation S230, the present apparatus calculates the expected arrival time T 1n ' of the (N+ 1)" 1 packets on the basis of the detected minimum time interval T 1n .
  • the present apparatus decodes the (N+ 1)" 1 and following received packets to generate reproducible voice data in operation S270.
  • the present invention stores the generated voice data in the reproduction buffer.
  • the present apparatus detects the extraction time T out of the voice (N+ 1)" 1 data when extracting/reproducing the voice data stored in the reproduction buffer.
  • the present apparatus calculates the data length of a compensation voice necessary for the fixed delay by subtracting the delay time D buf of the reproduction buffer from the fixed delay time D flx (i.e., D flx - D buf ).
  • the present apparatus reproduces the compensation voice (i.e., a silent signal) according to the calculated reproduction voice data length. Thereafter, in operation S290, the present apparatus extracts the (N+ 1)" 1 and following voice data from the reproduction buffer and reproduces the extracted voice data.
  • the compensation voice i.e., a silent signal
  • the invention can also be embodied as computer readable codes on a computer readable recording medium.
  • the computer readable recording medium is any data storage device that can store data which can be thereafter read by a computer system. Examples of the computer readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and carrier waves (such as data transmission through the Internet).
  • ROM read-only memory
  • RAM random-access memory
  • CD-ROMs compact discs
  • magnetic tapes magnetic tapes
  • floppy disks optical data storage devices
  • carrier waves such as data transmission through the Internet
  • the present invention compensates an initial delay variation of the variable-bandwidth multicodec to generate a fixed delay with a size desired by a called party, thereby making it possible to maintain a high-quality voice call.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Environmental & Geological Engineering (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)

Abstract

Provided is an apparatus and method for generating a fixed delay of a variable-bandwidth multicodec. In the method, the minimum time interval between an N number of received packets is detected and the expected arrival time of the (N+1)th packet is calculated on the basis of the detected minimum time interval. The (N+1)th and following packets are decoded and stored in a buffer. A delay time of the buffer is calculated on the basis of the difference between the calculated expected arrival time and the extraction time of voice data from the buffer. A compensation time is calculated on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer. A silent compensation voice is reproduced according to the calculated compensation time. Thus, a delay variation is compensated to generate a fixed delay.

Description

Description
Apparatus and method for generating fixed delay of variable- bandwidth multicodec
Technical Field
[1] The present invention relates to a variable-bandwidth multicodec, and more particularly, to an apparatus and method for generating a fixed delay of a variable- bandwidth multicodec by compensating a delay variation of the variable-bandwidth multicodec.
[2] This work was supported by the IT R&D program of MIC/IITA. [2005-S- 100-03,
Development of Multi-codec and its Control Technology Providing Variable Bandwidth Scalability] Background Art
[3] Variable-bandwidth multicodecs convert natural sounds into codec data with a plurality of data rates. For example, a variable-bandwidth multicodec classifies frequency bands into a narrow band (300 Hz ~ 3,400 Hz), a broad band (50 Hz ~ 7,000 Hz) and an audio band (20 Hz ~ 20,000 Hz), and calculates codec data with data rates of 8, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 and 32 bps in the respective bands.
[4] In a Voice over Internet Protocol (VoIP) voice call service of a packet network, a network band is variable and unpredictable and a variable-bandwidth multicodec has a 32 bps codec data rate providing the highest voice quality and an 8 bps codec data rate providing the lowest voice quality. In this case, when the network band is sufficient to transmit a high band, a 32 bps transmission band is transmitted using the variable- bandwidth multicodec. On the other hand, when the network condition becomes poor due to a change in the network band, a lower transmission band of 30 bps, 28 bps, etc. is transmitted using the variable-bandwidth multicodec so that the network transmission is facilitated while providing low voice quality.
[5] When a transmission data rate is high, the variable-bandwidth multicodec can provide high voice quality but has a high probability of causing transmission loss and delay in the network. On the other hand, when the transmission data rate is low, the variable-bandwidth multicodec provides low voice quality but has a low probability of causing transmission loss and delay in the network.
[6] A high-performance phone device is required for the reproduction operation of the variable-bandwidth multicodec. When the variable-bandwidth multicodec generates packets at intervals of 20 msec, the phone device must complete the encoding/ decoding operation of the variable -bandwidth multicodec within 20 msec in order to provide a normal call service. Up to now, the best-performance phone device requires an encoding/decoding time of 17 msec. However, because the encoding/decoding time point has no choice but to be fixed due to the long encoding/decoding time of the phone device, it is difficult to control a delay variation or generate a fixed delay by means of a conventional reproduction buffer algorithm. Disclosure of Invention Technical Problem
[7] The present invention provides an apparatus and method for generating a fixed delay of a variable-bandwidth multicodec by compensating a delay variation of the variable- bandwidth multicodec. Technical Solution
[8] According to an aspect of the present invention, there is provided an apparatus for generating a fixed delay, including: a packet receiver receiving packets; a delay variation detector detecting the minimum time interval between a predetermined number of packets, and calculating, based on the detected minimum time interval, the expected arrival time of a packet received after a predetermined number of the packets; a decoder generating voice data by decoding packets received after a predetermined number of the packets, and storing the generated voice data in a buffer; a delay calculator calculating a delay time of the buffer on the basis of the difference between the expected arrival time and the initial extraction time of the voice data from the buffer, and calculating a compensation time on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer; a compensation voice reproducer reproducing a silent compensation voice during the calculated compensation time; and a voice reproducer reproducing the voice data stored in the buffer after the reproduction of the silent compensation voice.
[9] According to another aspect of the present invention, there is provided a method for generating a fixed delay, including: receiving packets; detecting the minimum time interval between a predetermined number of packets, and calculating, based on the detected minimum time interval, the expected arrival time of a packet received after a predetermined number of the packets; generating voice data by decoding packets received after a predetermined number of the packets, and storing the generated voice data in a buffer; calculating a delay time of the buffer on the basis of the difference between the calculated expected arrival time and the initial extraction time of the voice data from the buffer, and calculating a compensation time on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer; reproducing a silent compensation voice during the calculated compensation time; and reproducing the voice data stored in the buffer after the reproduction of the silent compensation voice. Advantageous Effects
[10] As described above, when a variable-bandwidth multicodec requiring a high- performance phone is used in a high-quality real-time Internet phone service, the present invention compensates an initial delay variation of the variable-bandwidth multicodec to generate a fixed delay with a size desired by a called party, thereby making it possible to maintain a high-quality voice call. Description of Drawings
[11] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:
[12] FIG. 1 is a block diagram of an apparatus for generating a fixed delay of a variable- bandwidth multicodec by compensating a delay variation of the variable-bandwidth multicodec according to an embodiment of the present invention; and
[13] FIG. 2 is a flow diagram illustrating a method for generating a fixed delay of a variable-bandwidth multicodec by compensating a delay variation of the variable- bandwidth multicodec according to an embodiment of the present invention. Best Mode
[14] According to an aspect of the present invention, there is provided an apparatus for generating a fixed delay, including: a packet receiver receiving packets; a delay variation detector detecting the minimum time interval between a predetermined number of packets, and calculating, based on the detected minimum time interval, the expected arrival time of a packet received after a predetermined number of the packets; a decoder generating voice data by decoding packets received after a predetermined number of the packets, and storing the generated voice data in a buffer; a delay calculator calculating a delay time of the buffer on the basis of the difference between the expected arrival time and the initial extraction time of the voice data from the buffer, and calculating a compensation time on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer; a compensation voice reproducer reproducing a silent compensation voice during the calculated compensation time; and a voice reproducer reproducing the voice data stored in the buffer after the reproduction of the silent compensation voice.
[15] According to another aspect of the present invention, there is provided a method for generating a fixed delay, including: receiving packets; detecting the minimum time interval between a predetermined number of packets, and calculating, based on the detected minimum time interval, the expected arrival time of a packet received after a predetermined number of the packets; generating voice data by decoding packets received after a predetermined number of the packets, and storing the generated voice data in a buffer; calculating a delay time of the buffer on the basis of the difference between the calculated expected arrival time and the initial extraction time of the voice data from the buffer, and calculating a compensation time on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer; reproducing a silent compensation voice during the calculated compensation time; and reproducing the voice data stored in the buffer after the reproduction of the silent compensation voice. Mode for Invention
[16] The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.
[17] FIG. 1 is a block diagram of an apparatus for generating a fixed delay of a variable- bandwidth multicodec by compensating a delay variation of the variable-bandwidth multicodec according to an embodiment of the present invention.
[18] Referring to FIG. 1, the apparatus according to the present invention (hereinafter referred to as the present apparatus) includes a packet receiver 100, a delay variation detector 110, a delay calculator 120, a compensation voice reproducer 130, a decoder 140, a reproduction buffer 150, and a voice reproducer 160.
[19] The packet receiver 100 receives a voice packet and detects the arrival time of the received voice packet. The received voice packet is generally a user datagram protocol (UDP) packet. The packet receiver 100 transfers a predetermined number of packets, which are received from the initial call start time, to the delay variation detector 110; and transfers packets, which are received after a predetermined number of the packets received from the initial call start time, to the decoder 140. The predetermined number of the received packets transferred to the delay variation detector 110 may vary depending on embodiments of the present invention. In general, the received packets transferred to the delay variation decoder 110 may be about ten packets that do not carry important voice information. The following description will be made on the assumption that the predetermined number of the packets transferred from the packet receiver 100 to the delay variation detector 110 is 'N'.
[20] Using the variable-bandwidth multicodec, the decoder 140 decodes the (N+ 1)"1 and following packets, which are received from the packet receiver 100, to generate reproducible voice data. The reproduction buffer 150 stores the voice data generated by the decoder 140.
[21] The delay variation detector 110 detects the minimum time interval between the packets on the basis of the arrival times of the N voice packets received from the packet receiver 100. Also, the delay variation detector 110 calculates the expected arrival time of the (N+ 1)"1 packet on the basis of the detected minimum time interval. For example, if the minimum time interval between the received N packets is T1n, the expected arrival time Tm. of the (N+ 1)"1 packet is the sum of the minimum time interval Tin and the arrival time of the N"1 packet.
[22] The delay calculator 120 calculates the difference between the extraction time Tout when the voice reproducer 160 extracts the (N+l)"1 voice data (i.e., the (N+l)"1 packet) from the reproduction buffer 150 and the expected arrival time Tin' of the (N+ 1)"1 packet, which is calculated by the delay variation detector 110. The difference between the expected arrival time Tm. and the extraction time Tout is a packet delay time Dbuf of the reproduction buffer 150. The present invention aims at generating a fixed delay. Thus, the delay calculator 120 calculates the difference (hereinafter referred to as a compensation time) between a predetermined fixed delay time Dflx and the delay time Dbuf of the reproduction buffer 150.
[23] The compensation voice reproducer 130 reproduces a compensation voice (i.e., a silent signal) during the compensation time calculated by the delay calculator 120. The data length of the compensation voice reproduced by the compensation voice reproducer 130 is calculated by multiplying the compensation time by the voice data length per unit time.
[24] The voice reproducer 160 sequentially reproduces the voice data extracted from the reproduction buffer 150 after the reproduction of the compensation voice by the compensation voice reproducer 130. That is, even though the voice reproducer 160 extracts the (N+ 1)"1 voice data from the reproduction buffer 150 earlier, the extracted (N+ 1)"1 voice data is reproduced after the reproduction of the compensation voice during the compensation time calculated by the delay calculator 120.
[25] FIG. 2 is a flow diagram illustrating a method for generating a fixed delay of a variable-bandwidth multicodec by compensating a delay variation of the variable- bandwidth multicodec according to an embodiment of the present invention.
[26] Referring to FIG. 2, the present apparatus receives voice packets in operation S200.
The present apparatus compensates a predetermined (i.e., N) number of the initial and following received voice packets for a delay variation, uses the compensated voice packets in an operation for generation of a fixed delay, and decodes/reproduces the (N+ 1)"1 and following packets.
[27] In operation S210, the present apparatus determines whether the number of the received packets is smaller than or equal to N. If the number of the received packets is smaller than or equal to N (in operation S210), the present apparatus detects the minimum time interval T1n between the received packets on the basis of the detected arrival times of the received packets in operation S220. In operation S230, the present apparatus calculates the expected arrival time T1n' of the (N+ 1)"1 packets on the basis of the detected minimum time interval T1n.
[28] On the other hand, if the number of the received packets is larger than N (in operation S210) using the variable-bandwidth multicodec, the present apparatus decodes the (N+ 1)"1 and following received packets to generate reproducible voice data in operation S270. In operation S280, the present invention stores the generated voice data in the reproduction buffer.
[29] The present apparatus detects the extraction time Tout of the voice (N+ 1)"1 data when extracting/reproducing the voice data stored in the reproduction buffer. In operation S240, the present apparatus calculates the difference (i.e., the delay time Dbuf of the reproduction buffer) between the detected extraction time Tout and the calculated expected arrival time Tm. of the (N+ 1)"1 packet (Dbuf = Tout - T1n). In operation S250, the present apparatus calculates the data length of a compensation voice necessary for the fixed delay by subtracting the delay time Dbuf of the reproduction buffer from the fixed delay time Dflx (i.e., Dflx - Dbuf). In operation S260, the present apparatus reproduces the compensation voice (i.e., a silent signal) according to the calculated reproduction voice data length. Thereafter, in operation S290, the present apparatus extracts the (N+ 1)"1 and following voice data from the reproduction buffer and reproduces the extracted voice data.
[30] The invention can also be embodied as computer readable codes on a computer readable recording medium. The computer readable recording medium is any data storage device that can store data which can be thereafter read by a computer system. Examples of the computer readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and carrier waves (such as data transmission through the Internet). The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.
[31] As described above, when a variable-bandwidth multicodec requiring a high- performance phone is used in a high-quality real-time Internet phone service, the present invention compensates an initial delay variation of the variable-bandwidth multicodec to generate a fixed delay with a size desired by a called party, thereby making it possible to maintain a high-quality voice call.
[32] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

Claims
[1] An apparatus for generating a fixed delay, the apparatus comprising: a packet receiver receiving packets; a delay variation detector detecting the minimum time interval between a predetermined number of packets, and calculating, based on the detected minimum time interval, the expected arrival time of a packet received after a predetermined number of the packets; a decoder generating voice data by decoding packets received after a predetermined number of the packets, and storing the generated voice data in a buffer; a delay calculator calculating a delay time of the buffer on the basis of the difference between the expected arrival time and the initial extraction time of the voice data from the buffer, and calculating a compensation time on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer; a compensation voice reproducer reproducing a silent compensation voice during the calculated compensation time; and a voice reproducer reproducing the voice data stored in the buffer after the reproduction of the silent compensation voice.
[2] The apparatus of claim 1, wherein the packet receiver outputs a predetermined number of packets received from the initial call start time to the delay variation detector, and outputs packets received after a predetermined number of the received packets to the decoder.
[3] The apparatus of claim 1, wherein the decoder decodes packets using a variable- bandwidth multicodec.
[4] A method for generating a fixed delay, the method comprising: receiving packets; detecting the minimum time interval between a predetermined number of packets, and calculating, based on the detected minimum time interval, the expected arrival time of a packet received after a predetermined number of the packets; generating voice data by decoding packets received after a predetermined number of the packets, and storing the generated voice data in a buffer; calculating a delay time of the buffer on the basis of the difference between the calculated expected arrival time and the initial extraction time of the voice data from the buffer, and calculating a compensation time on the basis of the difference between a predetermined fixed delay time and the delay time of the buffer; reproducing a silent compensation voice during the calculated compensation time; and reproducing the voice data stored in the buffer after the reproduction of the silent compensation voice. [5] The method of claim 4, wherein the receiving of the packets comprises detecting the arrival time of a packet. [6] The apparatus of claim 4, wherein the storing of the generated voice data comprises decoding packets by means of a variable-bandwidth multicodec to generate voice data and storing the generated voice data in the buffer.
PCT/KR2008/004429 2007-12-17 2008-07-30 Apparatus and method for generating fixed delay of variable-bandwidth multicodec WO2009078535A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050111371A1 (en) * 2003-11-20 2005-05-26 Tsuyoshi Miura Apparatus and method for packet error correction
US20060173687A1 (en) * 2005-01-31 2006-08-03 Spindola Serafin D Frame erasure concealment in voice communications

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100744542B1 (en) * 2005-12-08 2007-08-01 한국전자통신연구원 Apparatus and method for multi-codec variable bandwidth QoS control

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050111371A1 (en) * 2003-11-20 2005-05-26 Tsuyoshi Miura Apparatus and method for packet error correction
US20060173687A1 (en) * 2005-01-31 2006-08-03 Spindola Serafin D Frame erasure concealment in voice communications

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