JP2009089257A - Multiple voice path switching method - Google Patents

Abstract

In a system having multiple audio paths, even when audio is simultaneously input to a plurality of microphones, an overinput state is blocked to prevent audio interruption.
In a system having multiple audio paths, a multi-link connection state is established between a plurality of microphones 21a, 21b, 21c,... For inputting audio and a mixer 32 for mixing audio input by a short-range wireless system. The mixer 32 receives the quantized data transmitted from the short-range wireless system, determines the characteristics of the multiple sound paths based on the optimum conditions, selects the optimum sound path, and outputs the selected sound path to the processing device.
[Selection] Figure 1

Description

  The present invention relates to a multiplexing voice path switching method for judging characteristics of a multiplexed voice path based on an optimum condition and selecting and switching an optimum voice path.

  An example of a system having multiple audio paths is a video conference system (see, for example, Patent Document 1).

  The video conference system may use a plurality of microphones (microphones) 11a, 11b, 11c,... As shown in FIG. The plurality of microphones 11a, 11b, 11c,... Are connected to the mixer 13 via cables 12a, 12b, 12c,. The mixer 13 mixes the audio signals input from the microphones 11a, 11b, 11c,... And inputs them to the existing video conference system 14. In addition to audio input means, the video conference system 14 includes, for example, a TV camera that captures conference participants and inputs the captured images, a speaker that outputs audio, an image processing device, a sound processing device, a transmission / reception control device, and the like. Yes.

In the system having multiple sound paths as described above, when a plurality of people input sound simultaneously to the plurality of microphones 11a, 11b, 11c,. As a result, the audio gain in the mixer 13 becomes an excessive input state, and the audio is interrupted.
JP-A-10-178624

  In a conventional system having multiple audio paths such as the video conference system 14, a plurality of microphones 11a, 11b, 11c,... Are input to the mixer 13 to be mixed, and the plurality of microphones 11a, 11b,. When a plurality of persons simultaneously input sound to 11c,..., The sound input from each microphone competes in the mixer 13, and as a result, the sound gain in the mixer 13 is over-input, It will cause interruptions.

  The present invention has been made in order to solve the above-described problems. By determining the characteristics of multiple audio paths based on the optimum conditions and selecting and switching the optimum audio paths, a plurality of people can be simultaneously connected to a plurality of microphones. An object of the present invention is to provide a multiple voice path switching method capable of reliably preventing voice interruption even when voice is input.

  The multiple audio path switching method according to the present invention includes a plurality of audio signal input means for inputting an analog audio signal, a quantizing means for quantizing the audio signal inputted by each of the input means, and each quantization A plurality of transmission units using a short-range wireless system that transmits the audio information quantized by the means to the outside, a reception unit that receives the audio information transmitted from each of the transmission units, and received by the reception unit And a mixer that selects and switches an optimal audio path based on the audio information, and a processing device that processes the audio information output from the mixer.

  According to the present invention, in a system having multiple audio paths, even if a plurality of analog audio signals are input simultaneously, an excessive input state of audio gain in the mixer is eliminated, and an audio discontinuity phenomenon is surely prevented. be able to.

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

  FIG. 1 illustrates a case where a multiple audio path switching method according to an embodiment of the present invention is applied to a video conference system.

  In FIG. 2, 21a, 21b, 21c,... Are a plurality of microphones (microphones) for inputting audio in the video conference system, and the audio signals input from the microphones 21a, 21b, 21c,. Are quantized by being input to the quantization circuits 22a, 22b, 22c,... And output as audio information (quantized data). The audio information output from the quantization circuits 22a, 22b, 22c,..., That is, the quantized data is input to the transmission units 23a, 23b, 23c,... Using the short-range wireless system, and the antennas 24a, 24b, 24c. , ... sent to the mixer.

  On the mixer side, a receiving unit 31 using the short-range wireless system is provided, and audio information (quantized data) transmitted from the antennas 24a, 24b, 24c,... Of the transmitting units 23a, 23b, 23c,. Is received by the antenna 30 and input to the mixer 32.

  As the short-range wireless system, for example, a Bluetooth (registered trademark) wireless system is used, and a multilink system is constructed between the plurality of microphones 21a, 21b, 21c,. The Bluetooth wireless system performs near field communication within about 10 m using a frequency in the 2.4 GHz band, and the communication speed is a maximum of 1 to 2 Mbps. When the above-described Bluetooth wireless system is used, simultaneous communication is possible between up to seven terminals, in this case, seven microphones 21a, 21b, 21c,. The plurality of microphones 21a, 21b, 21c,..., And the mixer 32 can be built with a Bluetooth chipset to construct a Bluetooth wireless system and perform short-range wireless communication.

  When the voice information (quantized data) received by the receiving unit 31 is sent, the mixer 32 determines the characteristics of the multiplexed voice path according to the optimum condition, selects the optimum voice path, and processes the quantized data. For example, the data is output to the terminal device 41 of the video conference system.

  There are the following two methods for the mixer 32 to switch the call path based on the optimum condition.

  (1) A method of switching the call path by calculating and comparing the absolute value of voice information (quantized data).

  (2) A method of sequentially passing audio information (quantized data) that reaches the mixer 32 in order.

  In the case of the above method (1), since the data quantized by the quantization circuits 22a, 22b, 22c,... On the microphone side also represents the level of audio gain, audio information (quantized data) has been received. The mixer 32 calculates the absolute value of the voice gain of the received data, and switches the call path so as to select the data with the largest voice gain by comparison.

  In the case of the method (2) above, the plurality of microphones 21a, 21b, 21c,... Transmit audio information (quantized data) from the transmitters 23a, 23b, 23c,. The voice information (quantized data) is compared in arrival order, and the call path is switched so that the paths are opened in order from the earliest arrival.

  The mixer 32 employs one of the two methods according to circuit conditions and the like, and switches the call path. The sampling period of the mixer 32 is set to 8 kHz, for example. When the sampling period is 8 kHz, the mixer 32 switches the call path within the processing time of 125 μsec, thereby ensuring a sufficient processing time that does not cause a voice interruption.

  The above video conference system is an ITU-T recommendation H.264 standard. A terminal device 41 standardized by 320 is provided, and this terminal device 41 is connected to an ISDN line 43 via a DSU (Digital Service Unit) 42. Although not shown, the terminal device 41 includes a television camera that captures a conference participant and inputs the captured image, a speaker that outputs sound, an image processing device, a sound processing device, a transmission / reception control device, and the like. The ISDN line 43 is connected to a communication partner terminal device (not shown) configured in the same manner as the terminal device 41.

  As described above, the analog audio signals input from the plurality of microphones 21a, 21b, 21c,... Are quantized by the quantization circuits 22a, 22b, 22c,. The analog speech is simultaneously input to the plurality of microphones 21a, 21b, 21c,... By selecting and switching the optimum call path based on the speech information (quantized data) received by the mixer 32. Even if it is a case, the excessive input state of the audio gain in the mixer 32 is eliminated, and the audio interruption phenomenon can be surely prevented. As a result, the progress of the video conference system is facilitated, and the conference efficiency is improved. Can be achieved.

  In the above embodiment, the case where three microphones are used has been described. However, the number of microphones can be arbitrarily set.

  Moreover, although the case where the Bluetooth wireless system was used as the short-range wireless system has been described in the above embodiment, it is needless to say that other wireless systems may be used.

  In the above-described embodiment, the case where the multiple audio path switching method is applied to the video conference system has been described. However, other systems can be implemented in the same manner as in the above-described embodiment.

  Further, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.

It is a block diagram which shows the structure of the switching system of the multiple audio | voice path | route which concerns on one Embodiment of this invention. In the conventional video conference system, it is a block diagram which shows schematic structure in the case of inputting an audio | voice using a some microphone.

Explanation of symbols

  21a, 21b, 21c, ..., microphone, 22a, 22b, 22c, ..., quantization circuit, 23a, 23b, 23c, ..., transmission unit, 24a, 24b, 24c, ..., antenna of the transmission unit, 30 ... Receiver antenna 31 ... Receiver 32 ... Mixer 41 ... Terminal device 42 ... DSU 43 ... ISDN line

Claims (1)

  A plurality of audio signal input means for inputting analog audio signals, a quantizing means for quantizing the audio signals input by the input means, and audio information quantized by the quantizing means respectively A plurality of transmission units using a short-range wireless system to transmit, a reception unit that receives audio information transmitted from each transmission unit, and an optimal audio path based on the audio information received by the reception unit A switching system for switching multiple audio paths, and a processing device for processing audio information output from the mixer.

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