JP2013074358A - Communication device, voice processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve voice quality of a data portion where a communication error has occurred in a communication device having a voice level adjusting function.SOLUTION: A communication device comprises: a receiving unit 10 for receiving a signal; a voice decoding unit 12 for decoding a voice signal from the received signal; a voice level adjusting unit 14 for adjusting the voice level of the decoded voice signal by either one of a first adjustment mode and a second adjustment mode; and a transmission state determination unit 15 for determining the reception state of the received signal. The voice level adjusting unit 14 switches the adjustment mode on the basis of the signal reception state determined by the transmission state determination unit 15. This structure allows for optimal voice level adjustment even if the reception state is determined to be a communication error, and improves voice quality of a data portion where a communication error has occurred.

Description

  The present invention relates to a communication device, a voice processing method, and a program. In particular, the present invention relates to a communication device having a function of adjusting a sound level, a sound processing method for adjusting a sound level, and a program thereof.

  In a communication device that receives and reproduces an audio signal, for example, in a cellular phone, the reproduced audio deteriorates due to a transmission error due to radio environment deterioration in wireless communication, and in an IP (Internet Protocol) phone, in the process of transmitting via the Internet. There is a problem that the reproduced voice is deteriorated due to the packet loss. In recent years, in order to solve these problems, it has been proposed to detect a communication error during transmission and correct an audio signal of a portion where the communication error has occurred by error concealment processing. It has also been proposed that when a communication error is detected, the received sound is made easy to hear by applying sound mute.

  Patent Document 1 discloses a communication terminal that performs appropriate audio mute level control according to a communication error state. FIG. 10 is a diagram for explaining a control operation of the communication terminal described in Patent Document 1. As shown in FIG. 10, this communication terminal switches and controls mute level control at the time of continuous error and mute level control at the time of intermittent error (mute level controls 1 to 4) according to the communication error state. . In this way, the received voice is improved by variably controlling the mute level of the received voice according to the communication error state.

JP 2000-59243 A

“Easy-to-use mobile phone“ Easy Phone Series ”, NTT Docomo Report No. 59, 2007.9.14, [Search September 19, 2011], Internet URL http://www.nttdocomo.co.jp/binary/pdf/info/news_release/report/070914.pdf

  The following analysis is given by the present invention.

  In recent years, as represented by “Raku Raku Phone” described in Non-Patent Document 1, a speech level adjustment function is provided after speech decoding processing to make it easy to hear the received speech even for elderly people or noise. Mobile phones equipped are commercialized. The “speech volume increase” function described in Non-Patent Document 1 senses the volume level of the other party's voice when the other party speaks low, and automatically increases the received volume.

  However, when the mobile phone having the sound level adjustment function described in Non-Patent Document 1 is used to perform the sound mute level control described in Patent Document 1, the following adverse effects occur. When a communication error occurs due to deterioration of the radio wave environment of wireless communication, mute processing is performed step by step with mute level control after error concealment processing, but the audio suppressed by the mute processing is automatically performed by the audio level adjustment function. Will be amplified. At this time, there may be a sense of incongruity in the level fluctuation in the reproduced sound, or the sound level immediately after the error is overloaded and an abnormal sound such as sound cracking may occur.

  In general, the error concealment process does not take into account the sound quality when there is a change in the sound level. Therefore, for the sound subjected to the error concealment process, the suppression by the mute process and the amplification by the sound level adjustment function are simultaneously performed. If this is done, the reproduced sound will have an unpleasant level fluctuation or a strange sound such as sound cracking, resulting in a problem that the sound quality deteriorates.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a communication apparatus having a sound level adjustment function, which improves the sound quality of a data portion where a communication error has occurred.

  A communication apparatus according to a first aspect of the present invention includes a receiving unit that receives a signal, a voice decoding unit that decodes a voice signal from the signal received by the receiving unit, and a first voice level of the decoded voice signal. An audio level adjustment unit that adjusts in accordance with any one of the adjustment mode and the second adjustment mode, and a transmission state determination unit that determines a reception state of the received signal, and the audio level adjustment unit includes: The adjustment mode is switched based on the reception state of the signal determined by the transmission state determination unit.

  An audio processing method according to a second aspect of the present invention is an audio processing method for receiving a signal including audio information, decoding the signal and converting it into an audio signal, and adjusting the audio level of the audio signal. A reception state determination step for determining a reception state of the received signal, and a step of stopping the adjustment of the audio level when the reception state determined in the reception state determination step is an error state.

  An audio processing method according to a third aspect of the present invention is an audio processing method for receiving a signal including audio information, decoding the signal and converting it into an audio signal, and then adjusting an audio level of the audio signal. A reception state determination step for determining a reception state of the received signal, and a step of slowing a response speed of the audio level adjustment when the reception state determined in the reception state determination step is an error state; including.

  According to a fourth aspect of the present invention, there is provided a program for determining a reception state of a received signal, and adjusting one of a first adjustment mode and a second adjustment mode for an audio signal obtained by decoding the signal. The computer executes a process for adjusting the audio level in the mode and a process for switching the adjustment mode based on the reception state.

  According to the communication apparatus of the present invention, it is possible to provide a communication apparatus that improves the audio quality of a data portion in which a communication error occurs in a communication apparatus having an audio level adjustment function. The reason is that the communication apparatus according to the present invention switches the adjustment mode based on the reception state of the received signal, so that the optimum audio level adjustment can be performed according to each reception state. For this reason, it is possible to make an optimum audio level adjustment even for a data portion in which a communication error occurs.

It is a block diagram which shows the receiving part and received audio | voice processing part of the communication apparatus which concern on one Embodiment of this invention. It is a block diagram which shows the receiving part and reception audio | voice processing part of the communication apparatus which concern on Embodiment 1 of this invention. It is a block diagram which shows the audio | voice level adjustment part of FIG. It is a figure for demonstrating operation | movement of the error concealment process part of FIG. It is a flowchart which shows operation | movement of the communication apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the communication apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the audio | voice level adjustment part of the communication apparatus which concerns on the modification of Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the communication apparatus which concerns on Embodiment 2 of this invention. It is a block diagram which shows the communication apparatus which concerns on Embodiment 2 of this invention. 6 is a diagram for explaining a control operation of a communication terminal described in Patent Document 1. FIG.

  First, the outline | summary of embodiment of this invention is demonstrated with reference to drawings as needed. It should be noted that the drawings cited in the description of the outline of the embodiments and the reference numerals of the drawings are shown as examples of the embodiments, and do not limit the variations of the embodiments according to the present invention.

  As shown in FIG. 1, the communication device according to an embodiment of the present invention includes a receiving unit 10 that receives a signal S1, a speech decoding unit 12 that decodes a speech signal S2 from the signal S1 received by the receiving unit 10, and a decoding A sound level adjustment unit 14 that adjusts the sound level of the sound signal S2 in accordance with one of the first adjustment mode and the second adjustment mode, and a transmission state determination unit 15 that determines the reception state of the received signal S1. The audio level adjustment unit 14 switches the adjustment mode based on the reception state of the signal S1 determined by the transmission state determination unit 15. With such a configuration, it is possible to perform optimum audio level adjustment for each reception state determined by the transmission state determination unit 15.

  When the transmission state determination unit 15 determines that the reception state of the signal S1 is an error state, the adjustment mode is set to the second adjustment mode, and in other cases, the adjustment mode is set to the first adjustment mode. May be. Thereby, when the signal S1 is in an error state, the sound quality of the signal S1 in the error state can be improved by setting the adjustment mode to the second adjustment mode.

  When the transmission state determination unit 15 continuously determines that the reception state of the signal S1 is an error state for a predetermined number of times or more, the adjustment mode is set to the second adjustment mode. In other cases, the adjustment mode is set to the first adjustment mode. The adjustment mode may be selected.

    In the second adjustment mode, the audio level adjustment by the audio level adjustment unit 14 may be stopped. Thereby, when the transmission state determination unit 15 determines that the reception state of the signal S1 is an error state, it is possible to eliminate the adverse effects caused by the amplification of the audio level adjustment unit 14.

  You may make it make the response speed of 2nd adjustment mode slower than the response speed of 1st adjustment mode. Thereby, when the transmission state determination unit 15 determines that the reception state of the signal S1 is an error state, it is possible to reduce the adverse effects caused by the amplification of the audio level adjustment unit 14.

  As shown in FIG. 2, when the reception state of the signal S1 is an error state, an error concealment processing unit 20 that corrects the signal S1 may be further provided.

  Further, as shown in FIG. 2, a mute unit 22 that suppresses the audio level of the signal S1 in accordance with correction by the error concealment processing unit 20, and an audio level adjustment control unit that performs control to switch the adjustment mode of the audio level adjustment unit 14a. The audio level adjustment control unit 18 performs control to switch the adjustment mode according to the reception state of the signal S1 determined by the transmission state determination unit 16 and the suppression operation by the mute unit 22. Also good. Thereby, it is possible to prevent the suppression operation by the mute unit 22 and the amplification operation by the audio level adjustment control unit 18 from being performed simultaneously.

  An audio processing method according to an embodiment of the present invention is an audio processing method in which a signal S1 including audio information is received, the signal S1 is decoded and converted into an audio signal S2, and then the audio level of the audio signal S2 is adjusted. If the reception state determined in the reception state determination step (step S12 in FIG. 5) for determining the reception state of the received signal S1 and the reception state determined in the reception state determination step is an error state, the adjustment of the audio level is stopped. Step (step S15 in FIG. 5).

  The audio processing method according to an embodiment of the present invention is an audio processing method that receives a signal S1 including audio information, decodes the signal and converts the signal into an audio signal S2, and then adjusts the audio level of the audio signal S2. If the reception state determined in the reception state determination step (step S12 in FIG. 5) for determining the reception state of the received signal S1 and the reception state determined in the reception state determination step is an error state, the response speed of the sound level adjustment is set. Slowing down.

  The program according to the embodiment of the present invention is a program for determining a reception state of the received signal S1, and for either the first adjustment mode or the second adjustment mode for the audio signal S2 obtained by decoding the signal S1. The computer causes the computer to execute a process for adjusting the audio level in the adjustment mode and a process for switching the adjustment mode based on the reception state. Here, the program is stored in the storage unit (58 in FIG. 6 and 86 in FIG. 9) and is executed by a computer provided in the control unit (52 in FIG. 6 and 80 in FIG. 9).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1

[Configuration of Embodiment 1]
FIG. 6 is a block diagram illustrating the communication apparatus 101 according to the first embodiment. The communication device 101 is a mobile phone terminal having a call function by wireless communication. As shown in FIG. 6, a mobile phone terminal (communication device) 101 includes an antenna 1 that transmits and receives radio waves, and a transmission unit 40 that modulates signals and transmits radio waves to a base station (not shown) via the antenna 1. A reception unit 42 that receives radio waves from the base station and demodulates the signal, a transmission audio processing unit 44 that processes an audio signal to be transmitted, and a reception audio processing unit that decodes the received signal and performs predetermined audio processing 46, a microphone 48 that collects the user's voice and supplies it to the transmission voice processing unit 44, a speaker 50 that outputs the voice signal processed by the reception voice processing unit 46 as voice, and the user performs various operations. An operation unit 56 to perform, a display unit 54 that displays various information to the user, a control unit 52 that performs overall control of the mobile phone terminal 101, and a storage unit 58 that stores various programs and various data. It has.

  Next, FIG. 2 shows the reception unit 42 and the reception voice processing unit 46 of FIG. 6, and is a block diagram showing a more detailed configuration especially regarding the reception voice processing unit 46. As shown in FIG. 2, the received voice processing unit 46 includes a voice decoding unit 12, an error concealment processing unit 20, a frame buffer 24, a mute unit 22, a voice level adjustment unit 14a, and a transmission state determination unit 16. The voice level adjustment control unit 18 is configured.

  First, the signal S1 received by the receiving unit 42 is an AMR or ITU-T specified by 3GPP. Since it is encoded by the encoding algorithm 729, the audio decoding unit 12 decodes the encoded signal and outputs the audio signal S2.

  Next, the error concealment processing unit 20 performs a process of correcting a frame of a portion where an error has occurred when the audio signal S2 includes an error due to deterioration of a radio wave environment at the time of transmission. FIG. 4 is a diagram for explaining error concealment processing performed by the error concealment processing unit 20. Several methods are conceivable for error concealment processing, and typical methods are shown in FIGS. 4 (a) to 4 (c).

  FIG. 4A shows a case where frames 2 and 3 are in an error state among a plurality of received audio frames. In the method shown in FIG. 4A, a process of replacing a frame in an error state with silence is performed. Thereby, it is possible to delete the abnormal sound generated when the audio signal S2 including the error state is reproduced. However, since the audio signal after the error concealment process is discontinuous at timings t1 and t2, unnaturalness occurs in the reproduced audio.

  FIG. 4B shows a case where frames 4 and 5 are in an error state among a plurality of received audio frames. In the method shown in FIG. 4B, a process of replacing a frame in an error state with a frame 3 that is not the previous error is performed. In order to perform such processing, the frame buffer 24 is used because it is necessary to temporarily store a frame signal that is not an error. Thereby, it is possible to delete the abnormal sound generated when the audio signal S2 including the error state is reproduced. However, since the audio signal after the error concealment process is discontinuous at the timing t3, unnaturalness occurs in the reproduced audio.

  FIG. 4C shows a case where frames 3 and 4 are in an error state among a plurality of received audio frames. In the method shown in FIG. 4C, a process of replacing an errored frame with frames before and after the error (frames 2 and 5) is performed. In this case as well, the frame buffer 24 is used to temporarily store frames that are not error before and after. Thereby, it is possible to delete the abnormal sound generated when the audio signal S2 including the error state is reproduced. However, since the audio signal after the error concealment process is discontinuous at the timing t4, unnaturalness occurs in the reproduced audio.

  Here, the determination of the error state in the error concealment processing unit 20 may use the result determined by the transmission state determination unit 16 described later, or the error concealment processing unit 20 may use a well-known FEC (Forward Error Correction; forward error). A correction) technique may be used to determine the error state.

  Next, the mute unit 22 has a function of suppressing the sound level, and reduces the unnaturalness of the sound due to the discontinuity of the sound signal (timing t1 to t4 in FIG. 4). Specifically, control is performed so that the mute unit 22 suppresses the sound level during the period in which the error concealment processing unit 20 performs the error concealment processing. In this way, by linking the error concealment processing unit 20 and the mute unit 22, a sound without unnaturalness can be obtained.

  Next, the transmission state determination unit 16 determines the reception state of the signal S1 received by the reception unit 42. Specifically, error detection is performed using a known FEC technique, and either a normal state (not an error state) or an error state is determined and output. Furthermore, the transmission state determination unit 16 has a counter that counts consecutive error states. When the number of consecutive error states reaches N (where N is a predetermined number set in advance and is a natural number), the reception state The determination result C1 is set to the High level, otherwise it is set to the Low level, and the reception state determination result C1 is output to the audio level adjustment control unit 18.

  Next, the audio level adjustment unit 14a will be described. FIG. 3 is a block diagram showing details of the audio level adjustment unit 14a. First, as shown in FIG. 3, the audio level adjustment unit 14 a includes an amplifier 26, a first gain control unit 28, and a switch 30.

  In FIG. 3, an amplifier 26 and a first gain control unit 28 operate as an auto gain control amplifier, and automatically adjust the audio signal S3 that has been subjected to mute processing to a predetermined audio level. Specifically, the first gain control unit 28 acquires the sound level of the mute-processed sound signal S3, automatically adjusts the gain of the amplifier 26 so that the sound level becomes a predetermined sound level, and the sound level is automatically adjusted. The audio signal S3 ′ thus output is output.

  Also, the two input terminals of the switch 30 are connected to the mute-processed audio signal S3 and the audio signal S3 ′ whose audio level is automatically adjusted, and the adjustment mode switching signal supplied from the audio level adjustment control unit 18 Switching control is performed by C2. Specifically, when the adjustment mode switching signal C2 is at the low level, the switch 30 selects and outputs the audio signal S3 ′ whose audio level is automatically adjusted, and when the adjustment mode switching signal C2 is at the high level, The switch 30 selects and outputs the muted audio signal S3 as it is.

  As described above, the audio level adjustment unit 14a has two adjustment modes and is configured to be switched by the adjustment mode switching signal C2. Here, the adjustment mode in which the switch 30 selects and outputs the audio signal S3 ′ whose audio level is automatically adjusted is the first adjustment mode, and the adjustment mode in which the switch 30 selects and outputs the mute-processed audio signal S3 as it is is the second. This is called the adjustment mode. The first adjustment mode corresponds to the “voice volume increase” function of “Raku-Raku Phone” described in Non-Patent Document 1, and when there is a voice signal, the average voice level becomes a predetermined voice level. Automatic adjustment is made. For example, if the predetermined sound level is set to -3 dBm, the unintelligible sound spoken by the other party is automatically averaged and amplified to -3 dBm, and the sound becomes easy to hear. On the other hand, the second adjustment mode is an adjustment mode for turning off automatic adjustment in the first adjustment mode.

  Next, the audio level adjustment control unit 18 will be described. The audio level adjustment control unit 18 receives the reception state determination result C1 output from the transmission state determination unit 16, and outputs the adjustment mode switching signal C2 to the audio level adjustment unit 14 based on the reception state determination result C1. To do. Specifically, when the reception state determination result C1 is at the low level, the adjustment mode switching signal C2 is set to the low level, and the audio level adjustment control unit 18 is set to the first adjustment mode. On the other hand, when the reception state determination result C1 is at the high level, the adjustment mode switching signal C2 is set to the high level, and the audio level adjustment control unit 18 is set to the second adjustment mode.

  As described above, when the reception state of the signal S1 received by the reception unit 42 is an error state continuous N times or more by the configuration of the reception voice processing unit 46 shown in FIG. The automatic adjustment is turned off. In other cases, the audio level is automatically adjusted in the first adjustment mode.

[Operation of Embodiment 1]
Next, the operation of the first embodiment will be described in detail with reference to FIGS. FIG. 5 is a flowchart showing the operation of the communication apparatus (mobile terminal apparatus) 101 according to the first embodiment. In FIG. 5, in the initial state, it is assumed that the adjustment mode of the sound level adjustment unit 14a is operating in the first adjustment mode. First, the receiving unit 42 receives the signal S1 (step S11). Next, the reception state of the signal S1 is determined by the FEC of the transmission state determination unit 16 (step S12).

  Next, when the transmission state determination unit 16 determines that the reception state is an error state, it is determined whether or not the transmission state is an error state that has continued N times or more (step S13). When it is determined NO in step S13, the audio level adjustment control unit 18 sets the adjustment mode of the audio level adjustment unit 14a to the first adjustment mode (step S14). On the other hand, when it is determined YES in step S13, the audio level adjustment control unit 18 sets the adjustment mode of the audio level adjustment unit 14a to the second adjustment mode (step S15). Then, it returns to step S11 and repeats a process.

  The above is the operation of the first embodiment shown in the flowchart of FIG. Hereinafter, the relationship between the operation of the mute unit 22 in Embodiment 1 and the operation of the audio level adjustment unit 14a controlled by the audio level adjustment control unit 18 will be described in more detail. The suppression operation of the mute unit 22 and the operation of switching the adjustment mode of the audio level adjustment unit 14a to the second adjustment mode are preferably interlocked. As described above, when correction is performed by the error concealment processing unit 20, the sound level is suppressed by the mute unit 22, but the amplification operation is not performed by automatic adjustment by the sound level adjustment unit 14a during that period. It is.

  Here, the following method can be used as a method of linking the suppression operation of the mute unit 22 and the operation of switching the adjustment mode of the audio level adjustment unit 14a to the second adjustment mode. As a first method, based on the reception state determined by the transmission state determination unit 16, the audio level adjustment control unit 18 predicts the suppression operation of the mute unit 22, and synchronizes with the suppression operation of the mute unit 22. This is a method for performing control to switch the adjustment mode of the level adjustment unit 14a to the second adjustment mode. The first method is used in the first embodiment. Specifically, when the transmission state determination unit 16 detects an error state continuously N times or more, it is predicted that the suppression operation of the mute unit 22 is in the suppression state. For this reason, it is determined in step S13 in FIG. 5 whether or not the error state continues N times or more.

  As a second method, as shown in FIG. 2, the mute unit 22 supplies the mute state C3 to the audio level adjustment unit 18 (indicated by a broken line in FIG. 2), and the audio level adjustment unit 18 transmits the transmission state determination unit 16. This is a method for performing control to switch the adjustment mode of the audio level adjustment unit 14a to the second adjustment mode using not only the reception state determined by the above but also the information of the mute state C3. Although the first method is used in the first embodiment, the second method may be used.

  In Step S13, there is another reason as described below as the reason for determining whether or not the error has continued N times or more. If N = 1, if it is determined that the error state has occurred even once, the adjustment mode switches from the first adjustment mode to the second adjustment mode, and then immediately returns to the normal state. In this case, the second adjustment mode is switched to the first adjustment mode, and the adjustment mode hunts, resulting in a sound that is difficult to hear. Therefore, it is preferable to switch to the second adjustment mode only when the error state continues N times or more to avoid hunting.

  In the first embodiment, as shown in FIG. 2, the audio level adjustment control unit 18 is provided. However, when the information of the mute state C3 is not used, the audio level adjustment control unit as shown in FIG. 18 may be configured such that the transmission state determination unit 15 directly outputs the adjustment mode switching signal C2 and switches the adjustment mode of the audio level adjustment unit 14.

  5 is stored in the storage unit 58 as a program, and is called and executed by a computer provided in the control unit 52. The steps S12, S13, S14, and S15 shown in the flowchart of FIG. The program can be downloaded via a network or updated using a storage medium storing the program.

  Hereinafter, effects of the first embodiment will be described. According to the mobile terminal 101 according to the first embodiment, when the received state of the received signal S1 is normal, the “voice volume increase” function of “Easy phone” described in Non-Patent Document 1 In addition, the audio level can be automatically adjusted. On the other hand, when the reception state of the received signal S1 is an error state, by turning off the automatic adjustment of the sound level, the voice quality of the part whose reception state is the error state in the communication device having the sound level adjustment function Can be improved. In other words, the voice level is amplified by turning off the automatic adjustment of the voice level in conjunction with the period during which the error concealment process and the mute process are performed on the voice signal of the part whose reception state is the error state. Can be avoided. As a result, it is possible to prevent the reproduced sound from generating strange sounds such as level fluctuations and sound cracks immediately after error recovery.

  In addition, according to the audio processing method in the first embodiment shown in FIG. 5, the audio processing capable of improving the audio quality of the portion in which the reception state is in the error state by appropriately switching the adjustment mode of the audio level adjustment. A method can be provided.

  In recent years, mobile phone terminals configured to automatically adjust the received voice level according to the noise level of the usage environment by inputting ambient noise from a microphone have been released. Even in such a cellular phone terminal, the same control as that of the voice level adjustment unit 14a and the voice level adjustment control unit 18 of the first embodiment can be performed, and the same effect as that shown in the first embodiment can be obtained.

[Modification of Embodiment 1]
Next, a communication device (portable terminal) according to a modification of the first embodiment will be described. A difference of the configuration of the first embodiment from the first embodiment is that the sound level adjustment unit 14a of the first embodiment is replaced with a sound level adjustment unit 14b shown in FIG.

  FIG. 7 is a block diagram illustrating an audio level adjustment unit 14b according to a modification of the first embodiment. In FIG. 7, the audio level adjustment unit 14 b includes an amplifier 26, a first gain control unit 28, a second gain control unit 32, and a switch 34. In FIG. 7, components having substantially the same functions as those in FIG. The first gain control unit 28 of FIG. 7 is the same as the first gain control unit 28 of the audio level adjustment unit 14a of the first embodiment. In the modification of the first embodiment, a second gain control unit 32 with a response speed delayed from that of the first gain control unit 28 is provided. The output of the first gain control unit 28 and the output of the second gain control unit 32 are connected to the two input terminals of the switch 34, respectively. The switch 34 is configured so that the above two inputs can be selected by the adjustment mode switching signal C2. Specifically, when the adjustment mode switching signal C2 is at the low level, the first gain control unit 28 is selected in the switch 34, and the sound level adjustment unit 14b enters the first adjustment mode. On the other hand, when the adjustment mode switching signal C2 is at the high level, the second gain control unit 32 is selected in the switch 34, and the sound level adjustment unit 14b is in the second adjustment mode.

  The second gain control unit 32 applies a known method of delaying the response speed in the auto gain amplifier. Thereby, the response speed of the automatic adjustment can be delayed in the second adjustment mode.

  According to the modification of the first embodiment, when the reception state of the received signal S1 is an error state, the voice quality of the portion where the reception state is an error state is delayed by delaying the response speed of the automatic adjustment of the sound level. Can be improved. That is, the audio level is amplified by delaying the response speed of the automatic adjustment of the audio level in conjunction with the period during which the error concealment process and the mute process are performed on the audio signal of the part whose reception state is the error state. Detrimental effects can be reduced. As a result, it is possible to prevent the reproduced sound from generating strange sounds such as level fluctuations and sound cracks immediately after error recovery.

Embodiment 2

  FIG. 9 is a block diagram illustrating the communication apparatus 102 according to the second embodiment. The communication device 102 is an IP telephone terminal having a call function via the Internet 1. As shown in FIG. 9, the IP telephone terminal (communication device) 102 includes a line connection unit 62 including a transmission unit 64 and a reception unit 66, a packet processing unit 68 that processes a packet to be transmitted and received, and a jitter of the received packet. A jitter buffer 70 for handling, a transmission voice processing unit 72 for processing a voice signal to be transmitted, a reception voice processing unit 74 for decoding a received signal and performing predetermined voice processing, and the like are provided. In FIG. 9, the microphone 76, the speaker 78, the control unit 80, the display unit 82, the operation unit 84, and the storage unit 86 are the microphone 48, the speaker 50, the control unit 52, the display unit 54, the operation unit 56, Since it has the same function as the storage unit 58, the description thereof is omitted.

  In the IP phone, packets are transmitted / received via the Internet 2 by RTP (Real-time Transport Protocol). IP telephones have a problem that packet loss occurs in the process of transmitting RTP packets via the Internet. Here, RTP used in IP telephone is a protocol that emphasizes the real-time nature of voice and does not have a retransmission mechanism corresponding to packet loss unlike TCP. Therefore, it is particularly important to improve the voice quality by detecting the packet loss and correcting the voice signal.

  In FIG. 9, the receiving unit 66 of the line connecting unit 62 receives a packet including voice information via the Internet 2. The received packet is temporarily stored in the jitter buffer 70, and the packet processing unit 68 performs processing corresponding to the switching of the packet order. The signal S 1 related to the audio data is extracted from the packets processed by the packet processing unit 68 and input to the received audio processing unit 74.

  Since the configuration of the reception voice processing unit 74 is the same as the configuration of the reception voice processing unit 46 in the mobile phone terminal 101 described in the first embodiment, the configuration of the reception voice processing unit 74 will be described with reference to FIG. explain. The audio decoding unit 12 decodes the received signal S1 and outputs an audio signal S2. Next, the error concealment processing unit 20 performs processing for correcting a frame of a portion where an error has occurred when an error corresponding to the packet loss is included in the audio signal S2. The processing algorithm of the error concealment processing unit 20 is the same as that in the first embodiment. Here, the determination of the error state in the error concealment processing unit 20 may use a result determined by the transmission state determination unit 16 described later, or may be performed by the error concealment processing unit 20. When an error state is determined inside the error concealment processing unit 20, a method based on the time stamp of the received RTP packet or a method of monitoring underflow in the jitter buffer 70 can be used. In the latter method, the packet processing unit 68 performs underflow due to the depletion of the jitter buffer 70, and the packet processing unit 68 supplies the result to the error concealment processing unit 20.

  Next, the transmission state determination unit 16 detects packet loss in the same manner as the error concealment processing unit 20. The transmission state determination unit 16 also uses the above-described method based on the time stamp of the RTP packet and the method of monitoring underflow in the jitter buffer 70.

  Further, the mute unit 22, the audio level adjustment unit 14a, and the audio level adjustment control unit 18 are the same as those in the first embodiment, and thus the description thereof is omitted. As described above, the configuration of the reception voice processing unit 74 of the second embodiment is the same as that of the reception voice processing unit 46 of the first embodiment when the error concealment processing unit 20 and the transmission state determination unit 16 determine the reception state. The only difference is that the RTP packet loss is changed to be detected.

  Next, the operation of the communication apparatus (IP telephone terminal) 102 according to the second embodiment will be described with reference to FIG. FIG. 8 is a flowchart showing the operation of the IP telephone terminal 102 according to the second embodiment.

  In FIG. 8, it is assumed that the adjustment mode of the audio level adjustment unit 14a is operating in the first adjustment mode in the initial state. First, the receiving unit 66 receives the signal S1 (step S21). Next, the transmission state determination unit 16 determines the reception state of the signal S1. That is, the presence / absence of packet loss is determined (step S22). As the reception state of the signal S1, the above-described method based on the time stamp of the RTP packet or the method of monitoring the underflow of the jitter buffer 70 is used.

  Next, when the transmission state determination unit 16 determines that the reception state is an error state, it is determined whether or not the transmission state is an error state that has continued N times or more (step S23). When it is determined NO in step S23, the audio level adjustment control unit 18 sets the adjustment mode of the audio level adjustment unit 14a to the first adjustment mode (step S24). On the other hand, if it is determined as YES in step S23, the audio level adjustment control unit 18 sets the adjustment mode of the audio level adjustment unit 14a to the second adjustment mode (step S25). Then, it returns to step S21 and repeats a process.

  8 is stored in the storage unit 86 as a program, and is called and executed by a computer provided in the control unit 80. The processes in steps S22, S23, S24, and S25 shown in the flowchart of FIG. The program can be downloaded via a network or updated using a storage medium storing the program.

  The effects of the second embodiment will be described below. According to the IP telephone terminal 101 according to the second embodiment, the reception state of the received signal S1 is determined by detecting the RTP packet loss, and the same processing as in the first embodiment is performed. The same effect as 1 is obtained. Further, the sound level adjustment unit 14a of the second embodiment can be replaced with the sound level adjustment unit 14b, and in this case, the same effect as that of the modification of the first embodiment can be obtained.

  The communication apparatus of the present invention is a mobile phone terminal having a function of automatically adjusting a voice level, such as “Raku-Raku Phone” disclosed in Non-Patent Document 1, or an IP phone terminal having a function of automatically adjusting a voice level. It is applicable to.

  Note that, within the scope of the entire disclosure (including claims) of the present invention, the embodiment or the embodiment can be changed or adjusted based on the basic technical concept. Various combinations and selections of various disclosed elements are possible within the scope of the claims of the present invention. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea.

1: Antenna 2: Internet 10, 42, 66: Reception unit 12: Audio decoding unit 14, 14a, 14b: Audio level adjustment unit 15, 16: Transmission state determination unit 18: Audio level adjustment control unit 20: Error concealment processing unit 22: mute unit 24: frame buffer 26: amplifier 28: first gain control unit 30, 34: switch 32: second gain control unit 40, 64: transmission unit 44, 72: transmission audio processing units 46, 74, 100: received voice processing unit 48, 76: microphone 50, 78: speaker 52, 80: control unit 54, 82: display unit 56, 84: operation unit 58, 86: storage unit 62: line connection unit 68: packet processing unit 70: Jitter buffer 101: Mobile phone terminal (communication device)
102: IP telephone terminal (communication device)
C1: Reception state determination result C2: Adjustment mode switching signal C3: Mute state signal S1: Signal S2: Audio signal S3: Mute-processed audio signal S3 ': Audio signal with automatically adjusted audio level S4: Audio level adjustment After audio signal

Claims (10)

A receiver for receiving the signal;
An audio decoding unit that decodes an audio signal from the signal received by the receiving unit;
An audio level adjustment unit that adjusts an audio level of the decoded audio signal in an adjustment mode of either the first adjustment mode or the second adjustment mode;
A transmission state determination unit for determining a reception state of the received signal,
The audio level adjustment unit switches the adjustment mode based on the reception state of the signal determined by the transmission state determination unit. When the transmission state determination unit determines that the signal reception state is an error state, the adjustment mode is the second adjustment mode,
The communication apparatus according to claim 1, wherein the adjustment mode is the first adjustment mode in other cases. When the transmission state determination unit determines that the reception state of the signal is an error state continuously for a predetermined number of times or more, the adjustment mode is set as the second adjustment mode,
The communication apparatus according to claim 1, wherein the adjustment mode is the first adjustment mode in other cases.   4. The communication apparatus according to claim 1, wherein in the second adjustment mode, the adjustment of the audio level by the audio level adjustment unit is stopped. 5.   4. The communication apparatus according to claim 1, wherein a response speed in the second adjustment mode is made slower than a response speed in the first adjustment mode. 5.   The communication apparatus according to claim 1, further comprising an error concealment processing unit that corrects the signal when the reception state of the signal is an error state. A mute unit that suppresses the audio level of the signal in accordance with correction by the error concealment processing unit, and an audio level adjustment control unit that performs control to switch the adjustment mode of the audio level adjustment unit,
The communication according to claim 6, wherein the audio level adjustment control unit switches the adjustment mode according to a reception state of the signal determined by the transmission state determination unit and a suppression operation by the mute unit. apparatus. An audio processing method for receiving a signal including audio information, decoding the signal and converting it into an audio signal, and adjusting an audio level of the audio signal,
A reception state determination step of determining a reception state of the received signal;
Stopping the adjustment of the audio level when the reception state determined in the reception state determination step is an error state;
A speech processing method comprising: An audio processing method for receiving a signal including audio information, decoding the signal and converting it into an audio signal, and adjusting an audio level of the audio signal,
A reception state determination step of determining a reception state of the received signal;
When the reception state determined in the reception state determination step is an error state, slowing down the response speed of the audio level adjustment;
A speech processing method comprising: A process for determining the reception state of the received signal;
A process of adjusting the audio level in the adjustment mode of either the first adjustment mode or the second adjustment mode for the audio signal obtained by decoding the signal;
A process of switching the adjustment mode based on the reception state;
A program that causes a computer to execute.

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