WO2009098975A1 - 音声ミキシング装置および方法ならびに多地点会議サーバ - Google Patents
音声ミキシング装置および方法ならびに多地点会議サーバ Download PDFInfo
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- WO2009098975A1 WO2009098975A1 PCT/JP2009/051302 JP2009051302W WO2009098975A1 WO 2009098975 A1 WO2009098975 A1 WO 2009098975A1 JP 2009051302 W JP2009051302 W JP 2009051302W WO 2009098975 A1 WO2009098975 A1 WO 2009098975A1
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- 238000005070 sampling Methods 0.000 claims abstract description 175
- 230000005236 sound signal Effects 0.000 claims description 276
- 238000004891 communication Methods 0.000 claims description 11
- 238000006243 chemical reaction Methods 0.000 abstract description 31
- 230000005540 biological transmission Effects 0.000 description 13
- 238000010586 diagram Methods 0.000 description 4
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M3/00—Automatic or semi-automatic exchanges
- H04M3/42—Systems providing special services or facilities to subscribers
- H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- G10L19/00—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
Definitions
- the present invention relates to a technique for mixing a plurality of audio signals, and more particularly, to an audio signal mixing technique used in a server or the like that provides a multipoint conference service.
- This multipoint video conference system includes a plurality of conference terminals and a multipoint control apparatus to which these conference terminals are connected. A conference terminal is assigned to the participant.
- each conference terminal transmits an acoustic signal related to sound (voice) detected by the terminal itself to the multipoint control device.
- the multipoint control device adds the acoustic signals received from the conference terminals.
- the multipoint control device subtracts the audio signal received from the conference terminal from the added audio signal for each conference terminal, encodes the audio signal obtained as a result of the subtraction, and outputs the encoded audio signal.
- a signal is transmitted to the conference terminal.
- the multipoint control device can be applied to various communication networks such as a circuit switching network, a mobile network, and a packet network.
- a circuit switching network H.264 of ITU-T (Telecommunication Union Telecommunication Standardization Sector) recommendation.
- a communication protocol defined by H.324 is used.
- a communication protocol defined by 3G-324M is used.
- a packet network based on IP Internet Protocol
- RFC3550 RTP of IETF The Internet Engineering Task Force
- the multipoint control device is equipped with a voice encoder for a telephone band voice having a sampling frequency of 8 kHz and a band of 3.4 kHz, or for a wideband voice having a sampling frequency of 16 kHz and a band of 7 kHz.
- Some are equipped with a speech coder.
- a speech coder for telephone band speech G.I. 711 and G.G.
- the AMR (Adaptive Multi-Rate) method adopted in 729, 3GPP and the EVRC (Enhanced Variable Rate Codec) method adopted in 3GPP2 are used.
- As a speech coder for wideband speech G.I.
- the AMR-WB (Wide Band) method specified in 722 and 3GPP TS26.190 is used.
- a codec such as MPEG-4 AAC (Advanced Audio Coding)
- the multipoint conference service can be used even between terminals that transmit and receive audio (acoustic) signals in different bands, such as terminals that use telephone bands and terminals that use broadband. It is desirable that it can be provided.
- the multipoint control device described above supports only a single-band audio signal, such as for telephone band audio or broadband audio, between terminals transmitting and receiving audio signals of different bands It is difficult to provide a multipoint conference service.
- An object of the present invention is to provide an audio mixing apparatus, an audio mixing method, and a multipoint conference server that can solve the above-described problems and can mix audio signals of a plurality of bands having different sampling frequencies.
- an audio mixing apparatus includes: It consists of multiple mixing processing units provided for each sampling frequency, Each of the plurality of mixing processing units includes: Input audio signals having the same sampling frequency are added to generate a first added audio signal, the sampling frequency of the first added audio signal is converted to a sampling frequency that can be processed by another mixing processing unit, and the sampling frequency To the other mixing processing unit The first added audio signal generated by the own processing unit and the first added audio signal which is supplied from the other mixing processing unit and converted to a sampling frequency that can be processed by the own processing unit. Are added to generate a second added audio signal.
- the audio mixing method of the present invention includes: A first step of classifying a plurality of input audio signals having different sampling frequencies into a plurality of groups according to the sampling frequency; For each group classified in the first step, input audio signals having the same sampling frequency are added to generate a first added audio signal, and the sampling frequency of the first added audio signal can be processed by another group A second step of converting to a different sampling frequency and assigning the audio signal having the converted sampling frequency to the other group; For each group classified in the first step, the first added audio signal generated in the own group and the sampling frequency allocated from the other group and processed in the own group are converted. And a third step of adding the first added audio signal to generate a second added audio signal.
- the multipoint conference server of the present invention is a multipoint conference server connected to a plurality of communication terminals via a network, A signal classification unit that classifies a plurality of audio signals received from the plurality of communication terminals by sampling frequency; A plurality of mixing processing units provided for each sampling frequency, and Each of the plurality of mixing processing units includes: Input audio signals having the same sampling frequency are added to generate a first added audio signal, the sampling frequency of the first added audio signal is converted to a sampling frequency that can be processed by another mixing processing unit, and the sampling frequency To the other mixing processing unit The first added audio signal generated by the own processing unit and the first added audio signal which is supplied from the other mixing processing unit and converted to a sampling frequency that can be processed by the own processing unit. Are added to generate a second added audio signal.
- FIG. 1 It is a block diagram which shows the structure of the audio
- FIG. 1 is a block diagram showing a configuration of an audio mixing apparatus according to an embodiment of the present invention.
- the audio mixing apparatus shown in FIG. 1 is mounted on a multipoint conference server, which is a multipoint control apparatus, and has k mixing processing units 1 1 to 1 k .
- the multipoint conference server can receive audio signals in a plurality of bands having different sampling frequencies, and a mixing processing unit is provided for each band. That is, the number of mixing processing units 1 1 to 1 k corresponds to the maximum number of bands that can be handled by the multipoint conference server.
- the multipoint conference server is configured to receive audio signals in k different bands B 1 to B k , and mixing processing units 1 1 to 1 k in which the received audio signals are provided for each band. To be supplied.
- FIG. 2 is a block diagram showing a configuration of a multipoint conference system using a multipoint conference server equipped with the audio mixing apparatus shown in FIG.
- This multipoint conference system includes a plurality of terminals 200 and a multipoint conference server 100 to which these terminals 200 are connected via a transmission path 300.
- the transmission line 300 includes a plurality of communication networks such as a circuit switching network, a mobile network, and a packet network.
- a circuit switching network such as a circuit switching network, a mobile network, and a packet network.
- the plurality of terminals 200 include a plurality of terminals having different audio signal bands and sampling frequencies transmitted and received via the transmission line 300.
- a terminal for telephone band voice having a sampling frequency of 8 kHz and a band of 3.4 kHz, a terminal for broadband voice having a sampling frequency of 16 kHz and a band of 7 kHz, and the like are used as the terminal 200.
- the configuration of each terminal 200 is basically the same.
- the terminal 200 includes an AD conversion unit 201, an encoding unit 202, a transmission unit 203, a DA conversion unit 204, a decoding unit 205, and a reception unit 206.
- the AD converter 201 converts the audio signal (analog signal) from the microphone 207 into a digital signal.
- the encoding unit 202 encodes the audio signal (digital signal) supplied from the AD conversion unit 201.
- the transmission unit 203 transmits the encoded audio signal supplied from the encoding unit 202 to the multipoint conference server 100 via the transmission path 300.
- the receiving unit 206 receives the encoded audio signal (digital signal) from the multipoint conference server 100 via the transmission path 300.
- the decoding unit 205 decodes the encoded audio signal supplied from the receiving unit 206.
- the DA converter 204 converts the decoded audio signal (digital signal) from the decoder 205 into an analog signal.
- the audio signal converted into the analog signal is supplied from the DA conversion unit 204 to the speaker 208.
- the multipoint conference server 100 includes a reception unit 101, a plurality of decoding units 102, a signal classification unit 103, an audio mixing device 104, and a transmission unit 105.
- the audio mixing device 104 is the audio mixing device shown in FIG.
- the receiving unit 101 receives an audio signal from each terminal 200 via the transmission path 300.
- the received audio signal is supplied from the receiving unit 101 to any of the plurality of decoding units 102.
- the decoding unit 102 decodes the audio signal supplied from the receiving unit 101.
- the decoded audio signal is supplied from the decoding unit 102 to the signal classification unit 103.
- the signal classification unit 103 converts the decoded audio signal supplied from the decoding unit 102 into a corresponding mixing processing unit among the mixing processing units 1 1 to 1 k shown in FIG. 1 according to the sampling frequency of the decoded audio signal. To supply. In addition, the signal classification unit 103 supplies the audio signal supplied from the audio mixing device 104 to the transmission unit 105.
- the sampling frequency of the decoded voice signal can be obtained from call control information obtained when the receiving unit 101 receives the voice signal.
- the transmission unit 105 transmits the audio signal supplied from the signal classification unit 103 to a corresponding terminal among the plurality of terminals 200 via the transmission path 300. Based on the call control information obtained when the reception unit 101 receives an audio signal, a terminal serving as a transmission destination can be identified.
- the audio mixing device 104 mixes and encodes a plurality of audio signals classified by sampling frequency supplied from the signal classification unit 103, and supplies the encoded audio signals to the signal classification unit 103.
- the audio mixing device 104 includes mixing processing units 1 1 to 1 k .
- the mixing processing units 1 1 to 1 k have basically the same configuration.
- FIG. 1 shows specific configurations of the mixing processing unit 1 1 , the mixing processing unit 1 2, and the mixing processing unit 1 k .
- the mixing processing unit 1 1 includes audio signal input terminals 10 1 to 10 n , a group signal addition unit 13 1 , sampling conversion units 14 1 to 14 k ⁇ 1 , an all signal addition unit 15 1 , and signal subtraction units 16 1 to 16 n. , Encoders 17 1 to 17 n and audio signal output terminals 19 1 to 19 n .
- the audio signal in the band B 1 is assigned to the audio signal input terminals 10 1 to 10 n .
- the received audio signals are supplied to the audio signal input terminals 10 1 to 10 n .
- the audio signal from the audio signal input terminal 10 1 is supplied to the first input of the signal subtracting unit 16 1 and also supplied to the group signal adding unit 13 1 .
- the audio signals from the audio signal input terminals 10 2 to 10 n are supplied to the first inputs of the signal subtracting units 16 2 to 16 n and also supplied to the group signal adding unit 13 1 .
- the group signal adding unit 13 1 adds the audio signals from the audio signal input terminals 10 1 to 10 n and outputs the addition result.
- the output of the group signal adder 13 1 is supplied to the sampling converters 14 1 to 14 k ⁇ 1 and the total signal adder 15 1 .
- Sampling converters 14 1 to 14 k ⁇ 1 are provided corresponding to other bands B 2 to B k excluding band B 1 .
- the sampling conversion unit 14 1 converts the sampling frequency of the audio signal (addition result) supplied from the group signal addition unit 13 1 to match the sampling frequency of the audio signal in the band B 2 .
- the sampling conversion unit 14 1 uses the audio signal from the group signal adding unit 13 1.
- the sampling frequency is converted from 8 kHz to 16 kHz.
- the sampling converters 14 2 to 14 k ⁇ 1 also convert the sampling frequency of the audio signal from the group signal adding unit 13 1 to the sampling frequency of the audio signal in the corresponding band.
- the output of the sampling converter 14 1 is supplied to all the signal addition unit of mixing processing unit 1 2 corresponding to band B 2.
- the outputs of the sampling converters 14 2 to 14 k ⁇ 1 are supplied to all signal adders of the mixing processors 1 3 to 1 k corresponding to the bands B 3 to B k .
- All signal adding unit 15 1 receives as input the sound signal from each group signal adder unit of the audio signal and the other mixing processing unit 1 2 ⁇ 1 k from group signal adder 13 1, adds the input audio signal To do.
- the output of all signal adder 15 1 is supplied to signal subtractors 16 1 to 16 n .
- the signal subtracting unit 16 1 uses the audio signal from the audio signal input terminal 10 1 as a first input, the audio signal from the all-signal adding unit 15 1 as a second input, and the first input from the second input. Output audio signal minus input. The output of the signal subtracting unit 16 1 is supplied to the encoding unit 17 1 .
- each of the signal subtracting units 16 2 to 16 n uses the audio signal from the corresponding input terminal of the audio signal input terminals 10 2 to 10 n as the first input, and uses the total signal adding unit 15 1. Is used as the second input, and the audio signal obtained by subtracting the first input from the second input is output.
- the output of the signal subtraction unit 16 2 ⁇ 16 n are supplied to the encoding unit 17 2 ⁇ 17 n.
- the encoding unit 17 1 encodes the audio signal from the signal subtracting unit 16 1 .
- the encoding units 17 2 to 17 n also encode the audio signal from the corresponding signal subtracting unit among the signal subtracting units 16 2 to 16 n .
- the output of the encoding unit 17 1 ⁇ 17 n is supplied to the audio signal output terminals 19 1 ⁇ 19 n.
- the audio signal output terminals 19 1 to 19 n supply the input audio signals to the signal classification unit 103 shown in FIG.
- Mixing processing unit 1 2 the audio signal input terminals 20 1 ⁇ 20 n, group signal adder 13 2, sampling conversion section 24 1 ⁇ 24 k-1, all the signal addition unit 15 2, signal subtraction unit 26 1 ⁇ 26 n , Encoders 27 1 to 27 n , and audio signal output terminals 29 1 to 29 n .
- the audio signal in the band B 2 is assigned to the audio signal input terminals 20 1 to 20 n .
- the number of audio signal input terminals 20 1 to 20 n may be the same as or different from the number of audio signal input terminals of other mixing processing units.
- the audio signal from the audio signal input terminal 20 1 is supplied to the first input of the signal subtracting unit 26 1 and also supplied to the group signal adding unit 13 2 .
- audio signals from the audio signal input terminals 20 2 to 20 n are supplied to the first inputs of the signal subtracting units 26 2 to 26 n and also supplied to the group signal adding unit 13 2 .
- the group signal adding unit 13 2 adds the audio signals from the audio signal input terminals 20 1 to 20 n and outputs the addition result.
- the output of the group signal adder 13 2 is supplied to the sampling converters 24 1 to 24 k ⁇ 1 and the total signal adder 15 2 .
- the sampling converters 24 1 to 24 k-1 are provided corresponding to the other bands B 1 and B 3 to B k excluding the band B 2 .
- the sampling conversion unit 24 1 converts the sampling frequency of the audio signal (addition result) supplied from the group signal addition unit 13 2 to match the sampling frequency of the audio signal in the band B 1 .
- the sampling converters 24 2 to 24 k ⁇ 1 also convert the sampling frequency of the audio signal from the group signal adding unit 13 2 to the sampling frequency of the audio signal in the corresponding band.
- the output of the sampling conversion section 24 1 is supplied to all the signal addition unit of mixing processing unit 1 1 corresponding to band B 1.
- the outputs of the sampling converters 24 2 to 24 k ⁇ 1 are supplied to all signal adders of the mixing processors 1 3 to 1 k corresponding to the bands B 3 to B k .
- the total signal adder 15 2 receives the audio signal from the group signal adder 13 2 and the audio signals from the group signal adders of the other mixing processing units 1 1 and 1 3 to 1 k , and inputs these input audios. Add the signals.
- the output of all signal adding unit 15 2 is supplied to signal subtracting units 26 1 to 26 n .
- the signal subtracting unit 26 1 uses the audio signal from the audio signal input terminal 20 1 as a first input, the audio signal from the all-signal adding unit 15 2 as a second input, and the first input from the second input. Output audio signal minus input. The output of the signal subtracting unit 26 1 is supplied to the encoding unit 27 1 .
- each of the signal subtracting units 26 2 to 26 n uses the audio signal from the corresponding audio signal input terminal of the audio signal input terminals 20 2 to 20 n as the first input, the audio signal from the 15 2 has a second input, and outputs a sound signal obtained by subtracting the first input from the second input.
- the output of the signal subtraction unit 26 2 ⁇ 26 n are supplied to the encoding unit 27 2 ⁇ 27 n.
- the encoding unit 27 1 encodes the audio signal from the signal subtracting unit 26 1 .
- the encoding units 27 2 to 27 n also encode the audio signal from the corresponding signal subtracting unit among the signal subtracting units 26 2 to 26 n .
- Output encoding unit 27 1 ⁇ 27 n is supplied to the audio signal output terminals 29 1 ⁇ 29 n.
- the audio signal output terminals 29 1 to 29 n supply the input audio signals to the signal classification unit 103 shown in FIG.
- the mixing processing unit 1 k includes audio signal input terminals 30 1 to 30 n , group signal addition unit 13 k , sampling conversion units 34 1 to 34 k ⁇ 1 , total signal addition unit 15 k , and signal subtraction units 36 1 to 36 n. , Encoders 37 1 to 37 n , and audio signal output terminals 39 1 to 39 n .
- the audio signal in the band B k is assigned to the audio signal input terminals 30 1 to 30 n .
- the number of audio signal input terminals 30 1 to 30 n may be the same as or different from the number of audio signal input terminals of other mixing processing units.
- the audio signal from the audio signal input terminal 30 1 is supplied to the first input of the signal subtracting unit 36 1 and also supplied to the group signal adding unit 13 k .
- audio signals from the audio signal input terminals 30 2 to 30 n are supplied to the first inputs of the signal subtracting units 36 2 to 36 n and also supplied to the group signal adding unit 13 k .
- the group signal adding unit 13 k adds the audio signals from the audio signal input terminals 30 1 to 30 n and outputs the addition result.
- the output of the group signal adder 13 k is supplied to the sampling converters 34 1 to 34 k ⁇ 1 and the total signal adder 15 k .
- Sampling converters 34 1 to 34 k-1 are provided corresponding to other bands B 1 to B k-1 other than band B k .
- the sampling conversion unit 34 1 converts the sampling frequency of the audio signal (addition result) supplied from the group signal addition unit 13 k so as to match the sampling frequency of the audio signal in the band B 1 .
- the sampling converters 34 2 to 34 k ⁇ 1 also convert the sampling frequency of the audio signal from the group signal adding unit 13 k to the sampling frequency of the audio signal in the corresponding band.
- the output of the sampling conversion section 34 1 is supplied to all the signal addition unit of mixing processing unit 1 1 corresponding to band B 1.
- the outputs of the sampling converters 34 2 to 34 k-1 are supplied to all signal adders of the mixing processors 1 1 to 1 k-1 corresponding to the bands B 1 to B k-1 .
- the total signal adding unit 15 k receives the audio signal from the group signal adding unit 13 k and the audio signal from each of the group signal adding units of the other mixing processing units 1 1 to 1 k ⁇ 1 as input signals. Is added. The output of all signal adding unit 15 k is supplied to signal subtracting units 36 1 to 36 n .
- the signal subtracting unit 36 1 uses the audio signal from the audio signal input terminal 30 1 as a first input, the audio signal from the all-signal adding unit 15 k as a second input, and receives the first input from the second input. Output audio signal minus input.
- each of the signal subtracting units 36 2 to 36 n also uses the audio signal from the corresponding audio signal input terminal among the audio signal input terminals 30 2 to 30 n as the first input, the audio signal from the 15 k and as a second input, and outputs a sound signal obtained by subtracting the first input from the second input.
- the output of the signal subtraction unit 36 1 ⁇ 36 n are supplied to the encoding unit 37 1 ⁇ 37 n.
- the encoding unit 37 1 encodes the audio signal from the signal subtracting unit 36 1 .
- the encoding units 37 2 to 37 n also encode the audio signal from the corresponding signal subtracting unit among the signal subtracting units 36 2 to 36 n .
- the output of the encoding unit 37 1 ⁇ 37 n is supplied to the audio signal output terminals 39 1 ⁇ 39 n.
- the audio signals input to the audio signal output terminals 39 1 to 39 n are supplied to the signal classification unit 103 shown in FIG.
- the configuration of the other mixing processing units 1 3 to 1 k-1 is basically the same as the configuration of the mixing processing units 1 1 , 1 2 , 1 k described above.
- FIG. 3 is a flowchart showing a procedure of mixing processing of the audio mixing apparatus shown in FIG.
- the operations of the mixing processing units 1 1 to 1 k are basically the same.
- the signal classifying unit 103 shown in FIG. 2 the operation of mixing processing unit 1 1 in the case where the audio signal band B 1 ⁇ B k is supplied to mixing processing unit 1 1 ⁇ 1 k, FIGS This will be described with reference to FIG.
- the sampling frequencies of the audio signals in the bands B 1 to B k are the sampling frequencies F 1 to F k , respectively.
- a plurality of audio signals S 1 to S n having a sampling frequency F 1 are supplied to the audio signal input terminals 10 1 to 10 n as audio signals in the band B 1 (step S10).
- Audio signals S 1 ⁇ S n from the audio signal input terminals 10 1 ⁇ 10 n is supplied to a first input of the signal subtraction unit 16 1 ⁇ 16 n, group signal a first input of the adder 13 1 To be supplied.
- group signal adder 13 1 generates a first addition voice signal by adding the audio signal S 1 ⁇ S n from the audio signal input terminals 10 1 ⁇ 10 n (step S11).
- the first added audio signal is supplied to sampling converters 14 1 to 14 k ⁇ 1 and full signal adder 15 1 .
- the sampling converter 14 1 converts the sampling frequency F 1 of the first added audio signal in the same band supplied from the group signal adder 13 1 to the sampling frequency F 2 .
- the sampling conversion section 14 2 ⁇ 14 k-1 is the sampling frequencies F 1 of the first addition voice signal of the same band supplied from group signal adder 13 1 of the sampling frequency F 3 ⁇ F k Convert to the corresponding sampling frequency.
- the first added audio signal in the same band whose sampling frequency is converted to the sampling frequency in the other band by the sampling converters 14 1 to 14 k ⁇ 1 is added to all the signals of the other mixing processors 1 2 to 1 k. Is supplied to the units 15 2 to 15 k (step S12).
- the all signal adder 15 1 converts the sampling frequency from the first added audio signal in the same band supplied from the group signal adder 13 1 and the other mixing processors 1 2 to 1 k. and other by adding the first addition audio signals of the same band, and outputs a second addition audio signals of the same sampling frequency F 1 (step S13). Second addition audio signals of the same sampling frequencies F 1 outputted from all the signal addition unit 15 1 is supplied to the signal subtraction unit 16 1 ⁇ 16 n.
- the signal subtracting unit 16 1 subtracts the input audio signal (first input) from the audio signal input terminal 10 1 from the second added audio signal (second input) from the total signal adding unit 15 1. Audio signal is output. Then, the encoding unit 17 1 encodes the audio signal from the signal subtracting unit 16 1 . Similarly, each of the signal subtraction unit 16 2 ⁇ 16 n is, from the second summing speech signals from all the signal addition unit 15 1 (second input), of the audio signal input terminals 10 2 ⁇ 10 n The audio signal obtained by subtracting the audio signal (first input) from the corresponding input terminal is output. Then, the encoding units 17 2 to 17 n encode the audio signals from the signal subtracting units 16 2 to 16 n (step S14).
- the outputs of the encoding units 17 1 to 17 n are supplied to the signal classification unit 103 shown in FIG. 2 via the audio signal output terminals 19 2 to 19 n (step S15).
- a plurality of terminals 200 shown in FIG. 2 transmits and receives a voice signal (for example, G.729 or AMR voice data) with a sampling frequency of 8 kHz, and a voice with a sampling frequency of 16 kHz.
- a voice signal for example, G.729 or AMR voice data
- a second terminal group that transmits and receives signals (for example, G.722 and AMR-WB audio data) and a third terminal that transmits and receives audio signals (for example, AAC audio data) with a sampling frequency of 32 kHz.
- Terminal group transmits and receives a voice signal (for example, G.729 or AMR voice data) with a sampling frequency of 8 kHz, and a voice with a sampling frequency of 16 kHz.
- a second terminal group that transmits and receives signals (for example, G.722 and AMR-WB audio data)
- a third terminal that transmits and receives audio signals (for example, AAC audio data) with a sampling frequency of
- Audio signal from the first terminal group is supplied to mixing processing unit 1 1, the audio signal from the second terminal group is supplied to mixing processing unit 1 2, the audio signal from the third terminal group mixing process It is supplied to the part 1 3.
- mixing processing unit 1 the procedure shown in FIG 3, the mixing process is performed for the audio signal from the first terminal group.
- sampling converter 14 the sampling frequency 8kHz of the addition sound signal of the same band from group signal adder 13 1 is converted into the processing capable sampling frequency 16kHz in mixing processing unit 1 2.
- the upsampling conversion from the sampling frequency of 8 kHz to the sampling frequency of 16 kHz for example, by inserting one sample having a value of 0 between each sample of the audio signal having the sampling frequency of 8 kHz, the audio having the number of samples doubled. Generate a signal. Then, the generated audio signal is passed through a band limiting filter that passes only a frequency band of 4 kHz or less, thereby obtaining an audio signal having a sampling frequency of 16 kHz.
- sampling conversion section 14 sampling frequency 8kHz of the addition sound signal of the same band from group signal adder 13 1, to the conversion processing in the mixing processor 1 3 capable sampling frequency 32 kHz.
- the number of samples is quadrupled by inserting three samples having a value of 0 between each sample of the audio signal having the sampling frequency 8 kHz. Generate an audio signal. Then, the generated audio signal is passed through a band limiting filter that passes only a frequency band of 4 kHz or less, thereby obtaining an audio signal having a sampling frequency of 32 kHz.
- band extension processing for adding a pseudo signal to a high band may be performed.
- bandwidth expansion processing see, for example, the publications “Yan Ming Cheng, O'Shaughnessy and D. Mermelstein,“ Statistical Recovery of Wideband Speech from Narrowband speech, ”Speech and Audio Processing, IEEE Transactions on Volume 2, 1994 pp.544-548.
- any mixing processing unit 1 2 the procedure shown in FIG. 3, the mixing process is performed for the audio signal from the second terminal group.
- This mixing process sampling converter 24 1, the sampling frequency 16kHz of the same band of the addition sound signal from group signal adder 13 2 is converted into the processing capable sampling frequency 8kHz in mixing processing unit 1 1.
- an audio signal having a sampling frequency of 16 kHz is passed through a band limiting filter that passes only a band having a frequency of 4 kHz or less and then thinned out for each sample.
- An audio signal having a sampling frequency of 8 kHz is obtained.
- sampling conversion section 24 sampling frequency 16kHz of the addition sound signal of the same band from group signal adder 13 2, converting processing in the mixing processor 1 3 capable sampling frequency 32 kHz.
- the generated audio signal is passed through a band limiting filter that allows only a frequency band of 8 kHz or less to pass, thereby obtaining an audio signal having a sampling frequency of 32 kHz.
- Any mixing processing unit 1 3 the procedure shown in FIG. 3, the mixing process is performed for the audio signal from the third terminal group.
- This mixing process sampling converter 34 1, the sampling frequency 32kHz of the addition sound signal of the same band from group signal adder 13 3, converted into process capable sampling frequency 8kHz in mixing processing unit 1 1.
- an audio signal having a sampling frequency of 32 kHz is passed through a band limiting filter that passes only a band having a frequency of 4 kHz or less, and then thinned every three samples.
- a band limiting filter that passes only a band having a frequency of 4 kHz or less, and then thinned every three samples.
- sampling frequency 32kHz of the addition sound signal of the same band from group signal adder 13 2 is converted into the processing capable sampling frequency 16kHz in mixing processing unit 1 2.
- an audio signal having a sampling frequency of 32 kHz is passed through a band limiting filter that passes only a band having a frequency of 8 kHz or less, and then thinned out for each sample.
- a band limiting filter that passes only a band having a frequency of 8 kHz or less
- each of the mixing processing units 1 1 to 1 k is capable of processing the sampling frequency of the inputted additional audio signal in the same band by another mixing processing unit. Convert to frequency. Furthermore, each of the mixing processing units 1 1 to 1 k has been converted into the added audio signal in the same band generated by the own processing unit and the sampling frequency of the own processing unit supplied from another mixing processing unit. The added audio signals in the same band are added to generate an added signal having the same sampling frequency. Each of the mixing processing units 1 1 to 1 k subtracts the input audio signal from the addition signal having the same sampling frequency, and encodes the audio signal obtained as a result of the subtraction.
- each of the mixing processing units 1 1 to 1 k converts the sampling frequency of the added audio signal in the same band into a sampling frequency that can be processed by another mixing processing unit, and is generated by the own processing unit.
- a plurality of different band audios It is possible to mix signals. Therefore, for example, a multipoint conference service can be provided between terminals that transmit and receive audio signals in different bands, such as terminals that use telephone bands and terminals that use broadband.
- each of the mixing processing units 1 1 to 1 k has been converted into the added audio signal of the same band generated by the own processing unit and the sampling frequency of the own processing unit supplied from another mixing processing unit.
- a pseudo audio signal having a predetermined high frequency component may be added to the added signal.
- audio mixing apparatus of the present embodiment is an example of the present invention, and the configuration and operation thereof can be changed as appropriate without departing from the spirit of the invention.
- the mixing processing units 1 1 to 1 k are the audio signals output from the all signal adding units 15 1 to 15 k or the audio data obtained by encoding the output audio signals. May be the respective output signals.
- the encoding units of the mixing processing units 1 1 to 1 k (for example, encoding units 17 1 to 17 k , 27 1 to 27 k , 37 1 to 37 k, etc.) However, it may be a predictive encoder.
- the decoding unit and the signal classification unit may be provided in the audio mixing apparatus or may be provided in the reception unit.
- the multipoint conference server shown in FIG. 2 can be realized by a computer system operated by a program.
- the main parts of this computer system are storage devices that store programs and data, input devices such as keyboards and mice, display devices such as LCD (Liquid Crystal Display), communication devices such as modems that communicate with the outside, printers It consists of a control device (CPU: Central Processing Unit) that operates according to the program stored in the storage device and the output device, and receives the input from the input device and controls the operation of the communication device, output device, and display device.
- a program for causing the CPU to execute the mixing process shown in FIG. 3 is stored in the storage device.
- This program may be provided through a recording medium or the Internet.
- a program for causing a DSP (Digital Signal Processor) to execute the mixing process shown in FIG. 3 can be provided as a program.
- DSP Digital Signal Processor
- a multipoint conference service can be provided between terminals that transmit and receive audio (sound) signals in different bands. Therefore, it is possible to improve convenience in the multipoint audio conference service.
- the present invention can be applied not only to a system that provides a multipoint conference service, but also to all devices that perform audio mixing.
- the present invention can be applied to a system that provides various media services realized by MRF (Media Resource Function) defined by 3GPP and MRCF (Media Resource Control Function) corresponding to a call control unit. it can.
- MRF Media Resource Function
- MRCF Media Resource Control Function
- the MRF and MRCF are used to realize the function of a so-called multipoint control unit (MCU) of a multipoint conference system.
- MCU multipoint control unit
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Abstract
Description
サンプリング周波数別に設けられた複数のミキシング処理部からなり、
前記複数のミキシング処理部のそれぞれは、
同一サンプリング周波数の入力音声信号を加算して第1の加算音声信号を生成し、該第1の加算音声信号のサンプリング周波数を他のミキシング処理部で処理可能なサンプリング周波数に変換し、該サンプリング周波数の変換がなされた音声信号を前記他のミキシング処理部に供給し、
自処理部で生成した前記第1の加算音声信号と、前記他のミキシング処理部から供給される、自処理部での処理が可能なサンプリング周波数への変換がなされた前記第1の加算音声信号とを加算して第2の加算音声信号を生成する、ことを特徴とする。
サンプリング周波数が異なる複数の入力音声信号をサンプリング周波数別に複数のグループに分類する第1のステップと、
前記第1のステップで分類したグループ毎に、同一サンプリング周波数の入力音声信号を加算して第1の加算音声信号を生成し、該第1の加算音声信号のサンプリング周波数を他のグループで処理可能なサンプリング周波数に変換し、該サンプリング周波数の変換がなされた音声信号を前記他のグループに割り当てる第2のステップと、
前記第1のステップで分類したグループ毎に、自グループで生成した前記第1の加算音声信号と、前記他のグループから割り当てられる、自グループでの処理が可能なサンプリング周波数への変換がなされた前記第1の加算音声信号とを加算して第2の加算音声信号を生成する第3のステップと、を含むことを特徴とする。
前記複数の通信端末から受信した複数の音声信号をサンプリング周波数別に分類する信号分類部と、
サンプリング周波数別に設けられた複数のミキシング処理部と、を有し、
前記複数のミキシング処理部のそれぞれは、
同一サンプリング周波数の入力音声信号を加算して第1の加算音声信号を生成し、該第1の加算音声信号のサンプリング周波数を他のミキシング処理部で処理可能なサンプリング周波数に変換し、該サンプリング周波数の変換がなされた音声信号を前記他のミキシング処理部に供給し、
自処理部で生成した前記第1の加算音声信号と、前記他のミキシング処理部から供給される、自処理部での処理が可能なサンプリング周波数への変換がなされた前記第1の加算音声信号とを加算して第2の加算音声信号を生成する、ことを特徴とする。
101~10n、201~20n、301~30n 音声信号入力端子
131~13k グループ信号加算部
141~14k-1、121~12k-1、131~13k-1 サンプリング変換部
151~15k 全信号加算部
161~16n、261~26n、361~36n 信号減算部
171~17n、271~27n、371~37n 符号化部
191~19n、291~29n、391~39n 音声信号出力端子
ミキシング処理部11は、音声信号入力端子101~10n、グループ信号加算部131、サンプリング変換部141~14k-1、全信号加算部151、信号減算部161~16n、符号化部171~17n、および音声信号出力端子191~19nを有する。
ミキシング処理部12は、音声信号入力端子201~20n、グループ信号加算部132、サンプリング変換部241~24k-1、全信号加算部152、信号減算部261~26n、符号化部271~27n、および音声信号出力端子291~29nを有する。
ミキシング処理部1kは、音声信号入力端子301~30n、グループ信号加算部13k、サンプリング変換部341~34k-1、全信号加算部15k、信号減算部361~36n、符号化部371~37n、および音声信号出力端子391~39nを有する。
Claims (8)
- サンプリング周波数別に設けられた複数のミキシング処理部からなり、
前記複数のミキシング処理部のそれぞれは、
同一サンプリング周波数の入力音声信号を加算して第1の加算音声信号を生成し、該第1の加算音声信号のサンプリング周波数を他のミキシング処理部で処理可能なサンプリング周波数に変換し、該サンプリング周波数の変換がなされた音声信号を前記他のミキシング処理部に供給し、
自処理部で生成した前記第1の加算音声信号と、前記他のミキシング処理部から供給される、自処理部での処理が可能なサンプリング周波数への変換がなされた前記第1の加算音声信号とを加算して第2の加算音声信号を生成する、音声ミキシング装置。 - 前記複数のミキシング処理部のそれぞれは、前記同一サンプリング周波数の入力音声信号毎に、前記第2の加算音声信号から該入力音声信号を差し引いた減算音声信号を生成し、該減算音声信号を符号化する、請求の範囲第1項に記載の音声ミキシング装置。
- 前記複数のミキシング処理部のそれぞれは、予め定められた高域成分を有する擬似音声信号を前記第2の加算音声信号に加える、請求の範囲第1項または第2項に記載の音声ミキシング装置。
- 前記複数のミキシング処理部のそれぞれは、
前記同一サンプリング周波数の入力音声信号を加算して前記第1の加算音声信号を生成するグループ信号加算部と、
前記グループ信号加算部にて生成された前記第1の加算音声信号と、前記他のミキシング処理部から供給される、自処理部での処理が可能なサンプリング周波数への変換がなされた前記第1の加算音声信号とを加算して前記第2の加算音声信号を生成する全信号加算部と、
前記同一サンプリング周波数の入力音声信号毎に設けられ、該入力音声信号が第1の入力として供給され、前記全信号加算部で生成された前記第2の加算音声信号が第2の入力として供給され、該第2の入力から該第1の入力を減算する複数の信号減算器と、
前記複数の信号減算器から出力された音声信号をそれぞれ符号化する複数の符号化部と、を有する、請求の範囲第1項乃至第3項のいずれかに記載の音声ミキシング装置。 - サンプリング周波数が異なる複数の入力音声信号をサンプリング周波数別に複数のグループに分類する第1のステップと、
前記第1のステップで分類したグループ毎に、同一サンプリング周波数の入力音声信号を加算して第1の加算音声信号を生成し、該第1の加算音声信号のサンプリング周波数を他のグループで処理可能なサンプリング周波数に変換し、該サンプリング周波数の変換がなされた音声信号を前記他のグループに割り当てる第2のステップと、
前記第1のステップで分類したグループ毎に、自グループで生成した前記第1の加算音声信号と、前記他のグループから割り当てられる、自グループでの処理が可能なサンプリング周波数への変換がなされた前記第1の加算音声信号とを加算して第2の加算音声信号を生成する第3のステップと、を含む、音声ミキシング方法。 - 前記第1のステップで分類したグループのそれぞれにおいて、前記同一サンプリング周波数の入力音声信号毎に、前記第2の加算音声信号から該入力音声信号を差し引いた減算音声信号を生成し、該減算音声信号を符号化するステップを、さらに含む、請求の範囲第5項に記載の音声ミキシング方法。
- 前記第1のステップで分類したグループのそれぞれにおいて、予め定められた高域成分を有する擬似音声信号を前記第2の加算音声信号に加えるステップを、さらに含む、請求の範囲第5項または第6項に記載の音声ミキシング方法。
- 複数の通信端末とネットワークを介して接続される多地点会議サーバであって、
前記複数の通信端末から受信した複数の音声信号をサンプリング周波数別に分類する信号分類部と、
サンプリング周波数別に設けられた複数のミキシング処理部と、を有し、
前記複数のミキシング処理部のそれぞれは、
同一サンプリング周波数の入力音声信号を加算して第1の加算音声信号を生成し、該第1の加算音声信号のサンプリング周波数を他のミキシング処理部で処理可能なサンプリング周波数に変換し、該サンプリング周波数の変換がなされた音声信号を前記他のミキシング処理部に供給し、
自処理部で生成した前記第1の加算音声信号と、前記他のミキシング処理部から供給される、自処理部での処理が可能なサンプリング周波数への変換がなされた前記第1の加算音声信号とを加算して第2の加算音声信号を生成する、多地点会議サーバ。
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JP2009552440A JP5158099B2 (ja) | 2008-02-04 | 2009-01-28 | 音声ミキシング装置および方法ならびに多地点会議サーバ |
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