JP2008060675A - Sound reproduction device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To synchronize the output timing of sounds reproduced by a plurality of audio reproduction devices receiving the data transmitted from the same audio source in a network. <P>SOLUTION: As an external sound picked up by a microphone connected with an audio reproduction device, its own reproduced sound is acquired and its own internal signal processing delay is measured at the timing of an internal reproduction audio signal obtained at a predetermined signal processing stage as a starting point. Reproduced sound of other device is also picked up, and the delay time of reproduced sound from other device is also measured at the timing of an internal reproduction audio signal as a starting point. Delay time of reproduced sound of other device for its own reproduced sound is measured by these delay times and output timing of the internal reproduction audio signal is varied in correspondence with this delay time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an audio reproducing apparatus that reproduces and outputs an audio signal as audio, and a method thereof.

  For example, as a so-called home network, a network for video / audio is being constructed and proposed. Incidentally, DLNA (Digital Living Network Alliance) has been formulated as one of the standards corresponding to such video / audio home networks (AV home networks). By conforming to DLNA, for example, an AV home network can be constructed with high versatility without being restricted by the same vendor.

  For example, in such an AV home network, video / audio content is transmitted from a device functioning as a server, and data (video signal, audio signal) as video / audio content is transmitted by an acoustic playback device (sound playback device) serving as a player. For example, it can be reproduced and output as sound such as music. In the case of a home network, a device that is a server that is a source of content and a device that is a player that receives and plays back the content are separated from each other as long as they are connected via the network. This is one of the advantages of the home network. In other words, without being limited to the installation location of the server device, for example, a player can be installed in an arbitrary room or location in the house to view and enjoy video / audio contents.

As an AV home network, data transmission / reception of video / audio contents between a server and a player is performed by network communication, for example. Therefore, for example, by using a transmission mode such as multicast, the same video / audio content is transmitted from a server to a plurality of players in a streaming format, and the content is reproduced and output almost simultaneously by these players. It becomes possible.
Then, as one form of use of the AV network, for example, in a situation where a family member who is a user frequently moves in the house by cleaning or the like, it is installed in a room away from one server. It is conceivable that the same audio content is transmitted to a plurality of audio reproduction devices and reproduced and output. In this way, the user can listen to the same audio content with sufficient volume and sound quality regardless of where the user moves in the house.

JP 2003-37585 A

  However, communication over a network is called a so-called best effort type, and a reduction in communication speed due to an increase in traffic or errors is allowed. For this reason, for example, as described above, even if the same audio content is simultaneously sent from a single server to a plurality of sound reproduction devices (players), the plurality of sound reproduction devices There is no guarantee that playback will be output at the same time. If the audio reproduction output timings between the plurality of audio reproducing apparatuses are shifted by a certain amount or more, the user who listens to it feels uncomfortable and uncomfortable, which is not preferable.

In view of the above-described problems, the present invention is configured as follows as an audio reproducing apparatus.
That is, the audio reproduction signal processing means for executing the signal processing for inputting the audio signal supplied from one audio signal output source and reproducing and outputting it as the audio, and the audio reproduced and output by the audio reproduction signal processing means From the collected sound signal of the microphone device provided so as to pick up the surrounding sound at a predetermined position determined according to the position where the generation source of the sound signal is installed, another sound reproduction device generates an audio signal output source. The other device output sound acquisition means for acquiring the sound signal component of the other device sound that is assumed to be in playback output by inputting the audio signal supplied from the other device, and the sound signal of the other device sound by the other device output sound acquisition means The audio reproduction signal processing means reproduces and outputs the audio having the reproduced audio content that is the same as the audio signal component of the other device audio when the component is acquired A time difference detecting means for detecting a time difference from the timing to be reproduced, and a reproduction output control means for controlling the sound reproduction signal processing means to change the timing at which the sound is reproduced and output based on the time difference detected by the time difference detecting means. It was decided to comprise.

In the audio reproducing apparatus of the present invention having the above-described configuration, an audio signal is input from one audio signal output source and reproduced and output as audio. In the present invention, it is assumed that the same audio signal supplied from the same audio signal output source is input and reproduced and output as a sound by another audio reproducing apparatus. Here, the audio signal output source refers to a device or a part that can output an audio signal through a predetermined output path regardless of inside or outside of the sound reproducing device of the present invention.
In addition, in the audio reproduction device of the present application, another audio reproduction device collects the sound (other device audio) that is input and reproduced by the same audio signal supplied from the same audio signal output source by the microphone. get. The timing at which the sound of the other device is picked up and acquired by the microphone and the timing at which the sound of the reproduced sound content that is the same as the sound of the other device is reproduced and output by the sound reproducing device of the present invention. Find the time difference. This time difference indicates the amount of deviation of the audio that should be reproduced and output at the same timing between the audio reproducing apparatus of the present invention and another audio reproducing apparatus. Therefore, for example, the timing at which the sound is reproduced and output is varied on the sound reproducing apparatus side of the present invention so that the deviation amount tends to be eliminated or reduced. As a result, the sound of the same sound source reproduced and output by the sound reproducing device of the present invention and another sound reproducing device can be output at the same time.

  In this way, depending on the present invention, synchronization is maintained so that the sounds of the same sound source reproduced and output by a plurality of sound reproducing devices are synchronized. As a result, for example, a user who is placed in a situation where he / she listens to the sound reproduced and output by the plurality of sound reproducing devices within a certain physical range does not feel a difference in sound. , You can get a comfortable listening environment.

  The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below. In the present embodiment, the audio reproduction device of the present invention is applied to an audio reproduction device that forms a home network (AV network) for video / audio.

FIG. 1 schematically shows an example of construction of an AV home network formed with the audio playback device of the present embodiment.
In this figure, a house 100 is shown first, and this house 100 is assumed to be divided into three rooms: a first room 101, a second room 102, and a third room 103. The server 11 is installed in the first chamber 101, and the audio playback devices 12 and 13 are installed in the second chamber 102 and the third chamber 103, respectively. One AV home network is constructed by interconnecting the apparatuses via the network line 1 so that they can communicate with each other.
It should be noted that the standard adopted as the network line 1 for constructing such an AV home network should not be limited in particular, and what is known so far, or what will be formulated in the future, etc. Any standard may be adopted, but in the present situation, DLNA (Digital Living Network Alliance) can be cited. As is well known, DLNA is intended as a home network for exchanging data of video content and audio content, and is intended to be as versatile as possible so that devices of different vendors can construct a network. It is standardized based on existing standards such as IP networks.

  The server 11 includes a relatively large-capacity storage medium represented by, for example, a hard disk, and stores and saves a large number of audio contents based on audio data in a predetermined format corresponding to, for example, music pieces. Yes. Then, for example, when the audio content is requested from the audio playback devices 12 and 13 via the network line 1, the requested audio content is read from the storage unit and transmitted to the requesting device in a stream format, for example. To be done.

In this case, the audio reproduction device 12 receives the audio content data sent from the server 11 via the network line 1 as described above, and reproduces and outputs it as sound from the speaker SP connected to the audio reproduction device 12. The audio reproduction device 12 shown in this figure can reproduce and output so as to correspond to a so-called multi-channel audio source such as 5.1ch surround.
Similarly, the audio playback device 13 also receives audio content data sent from the server 11 to itself, and plays back and outputs it as sound from the speaker SP connected thereto. In this figure, the audio playback device 13 is configured to support playback using, for example, L and R stereo channels.

Next, an example of the internal configuration of the server 11 will be described with reference to FIG.
The server 11 is configured so that, for example, the interface 41, the storage unit 42, and the control unit 43 are interconnected by an internal bus 45. Note that the delay time information holding unit 44 is a functional part provided in association with other embodiments to be described later, and therefore description thereof is omitted here.
The interface 41 is an interface function unit for connecting to the network line 2 corresponding to the home network 1, a hardware device corresponding to the physical layer for connecting to the network line 1 and performing communication, and predetermined software And a program corresponding to the hierarchy. The communication operation is controlled by the control unit 43.
For example, as described above, the storage unit 42 is configured by a storage medium such as a hard disk that can be relatively easily increased in capacity and cost in terms of cost and technology. The storage medium 42 stores and saves data of video / audio content corresponding to, for example, a musical piece unit. Such video / audio content data is managed in file units by a file system or the like.
The control unit 43 includes a computer system including, for example, a CPU (Central Processing Unit), a ROM, a RAM, and the like, and executes various control processes in the server 11.

  FIG. 3 is a block diagram illustrating an internal configuration example of each of the audio playback devices 12 and 13. For example, as described with reference to FIG. 1, the audio playback apparatuses 12 and 13 have different audio channel configurations, but the basic configurations can be handled in common. The configuration is shown in the same figure.

  In this figure, first, the interface 21 is an interface function unit for connecting to the network line 1, similarly to the interface 41 of the server device 11. When audio content data is streamed from the server 11, first, the interface 21 receives and acquires the audio content data as a packet. Then, the audio signal data is extracted from the packet and transferred to the reproduction data buffer 22A via the internal bus 36.

  As described above, audio signal data acquired by receiving the audio content transmitted from the server 11 is transferred to the reproduction data buffer 22A. In the reproduction data buffer 22A, the transferred audio signal data is stored in a state of being arranged and connected according to the original format, read out at a predetermined timing, and output to the signal processing unit 23.

The signal processing unit 23 performs necessary signal processing on the input audio signal data.
For example, audio signal data as audio content transmitted from the server 11 is subjected to compression encoding according to a predetermined method. Therefore, the signal processing unit 23 performs a decoding process (decompression process) corresponding to this compression encoding.
In addition, the signal processing unit 23 executes a decoding process corresponding to the audio channel configuration.
For example, as described above, the audio playback device 12 is adapted to support 5.1ch surround sound playback. Then, it is assumed that the audio content received and acquired from the server 11 is a 5.1ch surround source. This audio content has a structure in which, for example, audio signal data of a total of six audio channels corresponding to 5.1ch are multiplexed by a predetermined encoding method. When the audio playback device 12 receives such audio content data, the signal processing unit 23 performs decoding processing on the multiplexed audio signal data as described above to support 5.1ch. The audio signal data is divided into six audio channels.
Furthermore, the signal processing unit 23 can also perform signal processing such as sound quality adjustment and application of acoustic effects such as reverberation as necessary.

  The audio signal data that has undergone the signal processing of the signal processing unit 23 is transferred to the reproduction audio signal buffer 22B and temporarily stored therein. Then, reading is performed at an output timing corresponding to a delay time set as will be described later, and input to the first filter 24 at the subsequent stage. Actually, for example, as described above, if the audio playback device 12 is used, an audio output system for 6 channels corresponding to 5.1ch surround is required, and if the audio playback device 13 is used, L, R An audio output system for two channels corresponding to the stereo channel is required. In other words, the audio signal processing system subsequent to the audio signal buffer 22B is provided with a number corresponding to the audio channel. However, in this figure, these audio channels are collectively shown as one system for the sake of simplicity and ease of illustration.

  For example, as described later, the first filter 24 switches between a mode in which an input signal is passed (passed) as it is (all-pass mode) and a mode in which a passband characteristic in which only a predetermined frequency band is attenuated is set. It is supposed to be. The audio signal data that has passed through the first filter 24 is converted into an analog signal by the D / A converter 25, amplified by the amplifier 26, and output from the speaker output terminal 27 as a speaker drive signal. Although not shown here, a speaker is connected to the speaker output terminal 27, and the speaker is driven by the speaker drive signal. As a result, the audio signal data of the audio content transmitted from the server 11 is reproduced and output as sound from the speaker.

In addition, the audio playback devices 12 and 13 are provided with a microphone input terminal 28 to which a microphone M can be connected. In this case, the audio signal obtained by collecting sound by the microphone M is input to the second filter 29. As will be described later, the second filter 29 is switched between an all-pass mode that allows an input signal to pass (pass) as it is and a mode that operates as a band-pass filter that allows only a predetermined frequency band to pass. Then, the signal that has passed through the second filter 29 is converted into a digital audio signal (audio signal data) by the A / D converter 30 and input to the collected sound buffer 31.
Audio signal data (collected audio signal data) based on an audio signal obtained by collecting sound by the microphone M is input to the collected sound buffer 31. The collected sound buffer 31 temporarily stores the collected audio signal data. Using the collected audio signal data temporarily stored in the collected audio buffer 31 in this way, as described later, each of the audio reproducing devices 12 and 13 transmits the audio to be reproduced and output from itself. Control (sound reproduction synchronization control) for matching the output timing of the sound reproduced and output from the apparatus is executed.

Further, the delay time setting processing unit 32 is a part that executes a process for setting a delay time for a sound to be reproduced and output from itself for the above-described sound reproduction synchronization control. The delay time information holding unit 33 is an area in which information (delay time information) indicating the delay time set by the delay time setting processing unit 32 is held.
In correspondence with the actual hardware configuration, the delay time setting processing unit 32 can realize its function by the CPU in the control unit 34 executing a program stored in the ROM or the like. The The delay time information holding unit 33 may also use an area of a storage device such as a RAM or a non-volatile memory provided in the control unit 34.

The control unit 34 includes a microcomputer formed by combining, for example, a CPU, a ROM, a RAM, and the like, and executes various control processes for the audio playback devices 12 and 13.
Further, the microcomputer in the control unit 34 is configured to have a time measuring function. That is, the control unit 34 can measure the time and time by executing the internal clock counting process. Also, the internal bus 36 is used to execute control of each unit and exchange data internally.
The operation unit 35 generates various operation elements provided in the main body of the audio playback devices 12 and 13 and operation signals corresponding to operations performed on these operation elements to generate a control unit 34 (CPU). The operation signal output unit to be output is collectively shown. When the audio playback devices 12 and 13 are configured to be operated by a remote controller, the remote controller and the operation code signal transmitted from the remote controller on the main body side are received and used as an operation signal. A receiving unit that outputs to the control unit 34 is also included in the operation unit 35.

In the AV home network constructed by interconnecting the server 11 and the audio playback devices 12 and 13 with the above configuration, as is understood from the above description, the AV data is stored and stored in the storage unit 42 of the server 11. The audio content is received and acquired by the audio playback devices 12 and 13 as players, and signal processing for audio playback is executed, and the audio content can be played back and output from a speaker. In the present embodiment, as a mode of reproduction and output of audio content in such an AV home network, one common audio content among audio contents stored in the storage unit 42 of the server 11 is: Audio content data can be transmitted from the server 11 so as to be reproduced and output at the same timing by the audio reproducing devices 12 and 13.
In this way, by playing back and outputting the same audio content simultaneously by the audio playback devices 12 and 13, for example, a user using the AV home network goes back and forth between the second room 102 and the third room 103 of the house 100. Even in such a case, the reproduced sound having the same content can be heard in each room in a sufficiently clear state.

The audio content sending operation by the server 11 for enabling the simultaneous timing reproduction as described above is, for example, as follows.
The server 11 performs simultaneous timing reproduction by the audio reproduction devices 12 and 13 in accordance with the control of the control unit 43 in response to an appropriate operation procedure that is assumed to be performed on a predetermined device forming the AV home network. The audio content data designated as power is read from the storage unit 42 and transferred to the interface 41.
In the interface 41, the transferred audio content data is divided in units of packets in a format suitable for transmission via the network line 1. That is, a packet for storing audio content data is obtained. The packet is transmitted and output by multicasting with the audio playback devices 12 and 13 as the transmission destination.
Here, the timing at which the packets transmitted by multicast as described above are normally received and acquired by the audio playback devices 12 and 13 and the time from when the audio signal data is extracted from the received and acquired packets to be reproduced and output as sound. It is assumed that the difference in time is such that it is not perceived that the audio playback apparatuses 12 and 13 are deviated auditorily. If it does so, the audio | voice of the audio content reproduced | regenerated and output by each of the audio reproduction apparatuses 12 and 13 will almost correspond in the output timing.

  In addition, as the sending operation of the audio content by the server 11 for enabling the simultaneous timing reproduction, in addition to the multicast, the reproduction sound that is audibly heard can be transmitted within a time that is not deviated. It is also conceivable that packets storing data of the same audio content are transmitted and output to each of the audio playback apparatuses 12 and 13 by unicast.

  By the way, in actual network transmission, traffic increase or communication error occurs due to data transmission / reception that requires a very wide bandwidth or congestion. obtain. For this reason, the audio playback devices 12 and 13 are provided with a playback data buffer 22A, etc., and buffer the received audio signal data and temporarily store it, so that temporal continuity of audio signal playback is achieved. Is maintained. However, the amount of audio signal data to be accumulated by buffering is usually different depending on the specifications of each device. For example, this causes a deviation in the reproduction output timing of the audio content. Also, the processing delay until the buffered data is processed and output as sound often differs depending on the model of the audio playback device. For this reason, it can be said that there is a possibility that the audio output timing of each of the audio playback devices 12 and 13 may be shifted to an auditory level. Such a shift in the reproduced sound gives the user a sense of incongruity or discomfort. Therefore, in this embodiment, in order to avoid the inconveniences as described above, the audio playback apparatuses 12 and 13 side adopt a configuration for synchronized playback of audio contents as described below. .

FIG. 4 conceptually shows a process for synchronized playback performed by the audio playback devices 12 and 13. For convenience of simplifying the description, the audio playback device 12 will be described below.
First, FIG. 4A shows the timing of the internal playback audio signal and the external audio signal of the external device, which are assumed to have the same playback audio content. The internal playback audio signal is read from the playback audio signal buffer 22B in the audio playback device 12 as an audio signal (playback audio signal) that the audio playback device 12 receives from the server 11 and should be played back and output. The output timing is shown. The external audio signal indicates the timing at which the audio reproduction apparatus 12 reproduces and outputs the same reproduction audio signal as described above (that is, the reproduction audio signal having the same audio content obtained by reproduction) from the speaker. .
As the audio playback device 12, for example, the external audio signal acquisition timing (indicated by time t1) with respect to the appearance timing (indicated by time t0) of the internal playback audio signal shown in FIG. Delay time Dt1). The appearance timing of the internal playback audio signal can be recognized from the signal processing status inside the audio playback device 12. In addition, the appearance timing of the external audio signal of the external device is determined after the microphone M is installed at a position where the sound of the speaker (sound generation source) connected to the audio playback device 12 can be collected satisfactorily. It is possible to recognize from this collected sound signal by performing sound and obtaining a collected sound signal.
According to the above, the delay time Dt1 is, for example, output from the reproduction audio signal buffer 22B to the first filter 24, then reproduced and output as sound, and further collected by the microphone M and collected sound buffer. This is the time difference until the data is written to 31. That is, a system comprising a signal processing path after the first filter 24 in a system for reproducing and outputting reproduced audio signal data as sound and a sound collecting path for the sound from which the reproduced audio signal data is reproduced and output. The signal processing time required is shown.

  Next, as shown in FIG. 4B, the audio playback device 12 timings the external audio signal of the other external device having the same playback audio content as the internal playback audio signal with respect to the timing of the internal playback audio signal (time point t0). The delay time Dt2, which is the time difference of (time point t2), is measured. The external external device audio signal is collected by the microphone M after setting appropriate passbands (filter characteristics) for the first filter 24 and the second filter 29 as described later. It is obtained as a signal. Therefore, the delay time Dt2 is the time difference from when the audio reproduction device 12 transfers and outputs the reproduction audio signal data to the first filter 24 until the audio reproduction device 13 which is another device reproduces and outputs the sound. Then, the playback and output sound is picked up by the audio playback device 12 and transmitted in a time difference until it is written into the sound pickup sound buffer 31. Here, as the delay time Dt2, as shown in the figure, the result of measuring a time longer than the delay time Dt1 is shown.

  Then, as shown in FIG. 4B, a time (Dt2-Dt1) obtained by subtracting the delay time Dt1 from the delay time Dt2 is a reproduction audio signal to the first filter 24 in the audio reproduction device 12. The time from when the data is transferred and output until the audio is played back and output by the audio playback device 13 which is another device, and after the playback audio signal data is transferred and output to the first filter 24 in the audio playback device 12 This is a time obtained by subtracting the time until the reproduced audio signal data is reproduced and output as audio from the same audio reproducing device 12. In other words, assuming that the audio playback device 13 has the same processing configuration as the audio playback device 12, the processing delay time from the filter processing of the first filter 24 in the audio playback device 13 until sound output is performed. Therefore, the time (Dt2−Dt1) indicates a delay time for the audio output timing by the audio reproduction device 13 with respect to the audio output timing by the audio reproduction device 12.

Therefore, as shown in FIG. 4C, the audio playback device 12 shows the timing of the internal playback audio signal, that is, the timing at which the playback audio signal should be read from the playback audio signal buffer 22B and input to the first filter 24. Thus, the delay time Dtp set to coincide with the time (Dt2-Dt1) is delayed. In the figure, the timing at which the internally reproduced audio signal is delayed by the delay time Dtp from time t0 is shown as time t0a.
The internal reproduction audio signal input to the first filter 24 at the timing t0a passes through the time corresponding to the delay time Dt1 from the time t0a, as shown as the external own audio signal in FIG. 4C. However, this audio output timing is set to a time point t2 and is made to coincide with the audio signal from the other external device shown in FIG. 4B.
That is, the sounds output from the audio playback device 12 and the audio playback device 13 are synchronized so that their output timings coincide.

  As can be understood from the description of FIG. 4, the audio playback device 12 according to the present embodiment outputs other audio playback devices 13 by delaying the output timing of the sound played back by itself. Synchronize with audio. Therefore, when the timing is shifted so that the sound output from the audio playback device 13 is ahead in time, synchronization cannot be established on the audio playback device 12 side. At this time, the audio playback device 13 synchronizes the playback sound by delaying the timing of the sound to be played back and output by the operation described with reference to FIG.

By the way, in the process for audio reproduction synchronization shown in FIG. 4, the delay time difference between the audio timing output by itself and the audio timing output by the other device is finally obtained as the delay time Dtp. In this case, as shown in FIG. 4A, first, the delay time Dt1 corresponding to the internal signal processing time is obtained. In this way, the delay time Dtp is obtained in consideration of its own internal signal processing time, so that a highly accurate and reliable value can be obtained as the delay time Dtp.
However, for example, the internal signal processing is relatively simple, or the signal processing capability is very high, so the time required for the internal signal processing is a deviation in the output timing of the reproduced audio. In the case where the time is short enough not to be perceived, for example, the delay time Dt2 may be set as it is as the delay time Dtp for synchronization control without obtaining the delay time Dt1. .
Also, the internal signal processing time does not change greatly with the passage of time, such as the usage status of a network line, for example, and tends to maintain a constant state almost constantly. Therefore, the delay time Dt1 corresponding to the internal signal processing time is not actually obtained by using the collected sound signal, but a value obtained by a previous measurement or the like is set to 1 of the control parameter value. Alternatively, it may be stored as preset data from the time of factory shipment.

  Next, an example of the audio signal data reproduction processing procedure including the synchronous reproduction control, which is executed by the audio reproduction device 12 (13), will be described with reference to the flowcharts of FIGS. Note that the processing shown in these drawings is a processing operation realized by the CPU in the control unit 34 included in the audio playback device 12 (13) executing a program stored in a storage device such as a ROM. Can be seen. Such a program is written and stored in the ROM at the time of manufacture, for example, as described above, or stored in a removable storage medium and then installed from the storage medium. It is conceivable to store the data in an appropriate storage device or storage medium in the playback device 12 (13). In addition, the audio playback device 12 (13) is provided with a network function after being stored in a storage device in a server or the like on a network, and is downloaded and acquired from the server to obtain a predetermined storage device or storage medium. It is possible to install it.

The flowchart of FIG. 5 shows processing for the audio playback device 12 (13) to receive audio content.
Here, first, as shown in step S101, the interface 21 waits for reception of a packet storing audio content data transmitted from the server 11 to itself. Then, when a packet is received, the procedure of steps S102 and S103 is executed.

In step S102, the received audio content data packet is subjected to signal processing, and audio signal data to be reproduced and output (reproduced audio signal data) is extracted and acquired. In step S103, the reproduction audio signal data acquired in step S102 is transferred to and held in the reproduction audio signal buffer 22B via the reproduction data buffer 22A and the signal processing unit 23. As a result, the reproduction audio signal buffer 22B accumulates reproduction audio signal data.
In response to reception of the audio content data packet, the procedure of steps S101 to S103 is repeatedly executed.

Next, with reference to the flowchart of FIG. 6, a description will be given of a process for reading the reproduced audio signal data stored in the reproduced audio signal buffer 22B according to the procedure of FIG. Do.
Here, first, for example, the control unit 34 (CPU) reads the delay time information held in the delay time information holding unit 33 in step S201. The processing procedure for setting the delay time, which is information to be held in the delay time information holding unit 33, will be described later with reference to FIG.
In the subsequent step S202, the data read timing in the playback audio signal buffer 22B is set so that the timing of the audio to be played back is delayed by the delay time indicated by the delay time information read in step S201. To do. Then, in the next step S203, read control for the playback audio signal buffer 22B is executed at the set data read timing, and the playback audio signal data is output to the first filter 24. As a result, for example, as shown in FIG. 4C, the output timing of the internally reproduced audio signal is delayed, and as a result, the audio reproduction output timing coincides with the audio reproduction output timing of the other audio reproduction apparatus. To (synchronize).

Next, a procedure for setting a delay time by the delay time setting processing unit 32 will be described with reference to the flowchart of FIG.
First, the setting of the delay time is performed every predetermined time. This is not limited to the AV home network to which the audio playback device 12 (13) is connected, but can be applied to the entire network. Various situations and states of the network can change with the passage of time. Therefore, the communication speed between the audio playback device 12 or the audio playback device 13 and the server 11 may also change, and in this case, the delay time needs to be newly set. .
Therefore, in step S301, the system waits for the timing at which the delay time should be set, for example, by counting a predetermined time. Then, if it is determined that the timing for setting the delay time has been reached, the procedure after step S302 is executed.

  In step S302, as a preparatory process for capturing the collected sound signal as the external own audio signal shown in FIG. 4A, for example, the first filter 24 is determined in advance at a certain period of time. A band pass characteristic is set so that only the specified frequency band f is passed. In addition, about the 2nd filter 29, the mode (all pass mode) which passes an input signal as it is shall be set. At the same time, according to the procedure as step S303, the sound pickup audio signal is captured at a timing of a predetermined time length corresponding to the timing at which the first filter 24 passes the frequency band f and the band pass characteristic is set. Execute. That is, a collected sound signal, which is a sound signal obtained by collecting sound by the microphone M, is taken in as a digital signal via the second filter 29 and the A / D converter 30, and the collected sound buffer 31. Is input and held.

Depending on the next step S304, the delay time Dt1 of the external audio signal with respect to the internal reproduction audio signal described with reference to FIG. 4A is obtained and acquired.
For this purpose, the collected sound signal held in the collected sound buffer 31 in the previous step S303 and the data held in the reproduction audio signal buffer 22B, for example, by waveform analysis processing or the like. To be compared. By this comparison processing, a waveform section which is assumed to be composed only of the predetermined frequency band f in the collected sound signal (a band other than the frequency band f is attenuated (cut)) is specified. Next, a time timing (time) at which a waveform section composed only of the predetermined frequency band f is picked up, and a time timing at which band pass characteristics in which only the frequency band f is passed in the first filter 24 are set. The difference from (time) is obtained. This difference is the delay time Dt1. In step S304, for example, the delay time Dt1 is acquired in this way.
Further, in the processing of this figure, in response to the completion of the acquisition of the delay time Dt1, the all-pass mode is once set (reset) for the first filter 24 in step S305.

  Next, in step S306, band pass characteristics in which only a predetermined specific frequency band fa is cut (attenuated) with respect to the first filter 24 provided in the reproduction signal processing system of the reproduction audio signal data. Set. At the same time, in the subsequent step S307, the second filter 29 provided in the input stage of the collected sound signal cancels the all-pass mode and passes only the specific frequency band fa. To set the characteristics. Then, in step S308, control processing for capturing the collected sound signal into the collected sound buffer 31 is executed.

  The collected sound signal captured in step S308 is the external other-device audio signal shown in FIG. That is, first, by setting the pass band characteristic for the first filter 24 in step S306, the speaker sound by the audio reproduction device 12 has a band characteristic in which only the frequency band fa is attenuated. On the other hand, the second filter 29 has a passband characteristic that allows only the frequency band fa to pass, which is the same as picking up ambient sound of only the frequency band fa depending on the microphone M. Therefore, depending on step S308, the speaker sound by the audio playback device 12 itself is not picked up in the same way as being silent, and instead is masked by the speaker sound of the audio playback device 12 instead. The sound that the speaker sound of the audio playback device 13 leaks into the second chamber is collected. In other words, depending on step S308, as described above, only the component of the external external device audio signal is captured as the collected sound signal.

Depending on the next step S309, as shown in FIG. 4B, first, a delay time Dt2, which is a delay time difference of the time timing of the external audio signal from the external device with respect to the time timing of the internal reproduction audio signal, is obtained. To be done.
For this purpose, for example, the data of the collected sound signal (external other device audio signal) that is assumed to be held in the collected sound buffer 31 by the procedure of step S308 and the reproduction audio signal buffer 23 are stored. A comparison process using, for example, a waveform analysis process is performed on the data of the reproduced audio signal (internally reproduced audio signal). As a result of this comparison processing, the time timing (time) at which the internal playback audio signal is output from the playback audio signal buffer 22B to the first filter 24 for the audio signal portion having the same playback content, and the external others The difference (time difference) from the time timing (time) at which the machine audio signal (collected sound signal) is held in the collected sound buffer 31 is obtained. This time difference is the delay time Dt2.

  If it is assumed that the external external device audio signal is taken in as the collected sound signal as described above, then, in step S310, the delay time Dtp to be set for the reproduced audio signal is obtained and acquired. That is, the delay time Dtp is obtained by calculating Dt2−Dt1. Then, the delay time information held so far by the delay time information holding unit 33 is updated so that the value of the delay time Dtp obtained in this step S304 is indicated.

  In step S311, the band pass characteristics of the first filter 24 and the second filter 29 set in the previous steps S306 and S307 are canceled, the all-pass mode is reset, and the process returns to step S301.

  In the procedure shown in FIG. 7, in order to obtain the required time timing (time) for obtaining the delay times Dt1 and Dt2 as well as the timing for waiting for the delay time setting timing in step S301, For example, a clocking function assumed to be provided in the microcomputer in the control unit 34 may be used. For example, the microcomputer of the control unit 34 can measure the time and time by counting the internal clock and the like, thereby realizing the above-described time measuring function.

  Here, in the procedure shown in FIG. 6, the audio playback device 12 performs the audio output playback based on the delay time information (delay time Dtp) held in the delay time information holding unit 33. The process of variably controlling the read timing from the reproduction data buffer 22 is repeated. The delay time information held in the delay time information holding unit 33 is updated at regular intervals according to the procedure of FIG. 7, so that the delay time Dtp always adapted to the current actual audio output delay situation. Have a value. In this way, the procedure of FIG. 6 and the procedure of FIG. 7 are executed in parallel, so that, for example, the output timing of the reproduced sound between the audio reproducing devices 12 and 13 with the passage of time. Even if the amount of deviation changes, it is possible to synchronize the reproduced sound by following this.

Next, another embodiment of the present invention will be described.
For example, the delay time Dtp actually obtained depends on the time difference of the output timing of the reproduced sound between the audio reproducing apparatuses that can actually occur and the condition of the maximum delay time for the reproduced audio signal data in the audio reproducing apparatus. However, it may be possible that the maximum delay delay time is exceeded and reproduction synchronization cannot be achieved properly. In view of this, as another embodiment, a configuration is proposed for synchronizing the output timing of the reproduced sound between the audio reproducing apparatuses 12 and 13 even in such a situation.

  A configuration for reproduction audio synchronization as another embodiment will be described with reference to a flowchart of FIG. The procedure shown in FIG. 7 is executed by the audio playback device 12 (13), and should be executed in place of step S310 in the flow of the processing procedure in FIG. That is, in another embodiment, as the processing procedure of FIG. 6, after executing steps S301 to S309, the procedure shown in FIG. 8 is executed and then step S310 is executed. .

First, in step S401 in FIG. 8, the delay time Dtp is obtained in the same manner as in the original step S310 in FIG. In another embodiment, the delay time Dtp obtained in step S401 is referred to as “actual delay time” as it is actually occurring, and is held in the delay time information holding unit 33. It is distinguished from delay time (set delay time Dtp1) which is delay time information.
In addition, in the next step S402, it is determined whether or not the actual delay time Dtp calculated in step S401 exceeds the maximum delay possible time Dtmax.

  If an affirmative determination result is obtained in step S402, the audio playback device 12 (13) itself reads the playback audio signal data from the playback data buffer 22 at the read timing according to the setting of the maximum delay time Dtmax. Even if the output is executed, the delay time is still insufficient and it cannot be synchronized with the audio output timing of the other audio reproducing apparatus. Therefore, in this case, steps S403 and S404 are executed.

First, in step S403, the maximum delay possible time Dtmax is set here as the set delay time Dtp1 to be used for setting the data read timing from the playback audio signal buffer 22B for the playback audio signal data. . Then, the delay time information held in the delay time information holding unit 33 is rewritten (updated) by the set delay time Dtp1 having a value as the maximum delay possible time Dtmax.
Then, depending on the next step S404, a delay time assistance request is transmitted to the server 11 via the network line 1. Along with this delay time assistance request, a time value represented by Dtp−Dtmax is designated as the assistance delay time Dsp. In other words, the audio playback device 12 (13) requests the server 11 to have the server 11 delay the time that exceeds the maximum delay possible time Dtmax in the actual delay time Dtp. Is to do.

As a result of the execution of the procedures in steps S403 and S404, first, the audio playback device 12 (13) plays back the playback audio signal data based on the delay time information in the delay time information holding unit 33 updated in step S403. Is delayed by a delay time corresponding to the maximum delay possible time Dtmax.
At the same time, the server 11 that has received the delay time auxiliary request holds the information of the auxiliary delay time Dsp transmitted together with this request in the delay time information holding unit 44 shown in FIG. The delay time information holding unit 44 should be provided according to this other embodiment, and is a part that holds information on the auxiliary delay time Dsp as described above. As an actual delay time information holding unit 44, for example, a partial storage area of a storage device such as a RAM provided in the control unit 43 is used. In the server 11, when sending the audio content packet, the audio playback device 12 (13) as the transmission source of the delay time auxiliary request according to the time indicated by the auxiliary delay time Dsp held in the delay time information holding unit 44. The transmission timing of the audio content data packet is delayed. As a result, in the audio playback device 12 (13) that has made the delay time auxiliary request, the reception timing of the audio content packet is delayed by the time corresponding to the auxiliary delay time Dsp. A delay corresponding to the auxiliary delay time Dsp is also obtained as the audio output timing for the reproduced audio signal data of the audio content. In addition, as described above, in the audio reproduction device 12 (13), reproduction output is performed with a delay time corresponding to the maximum delay possible time Dtmax. As a result, a delay corresponding to the time represented by the maximum delay possible time Dtmax + auxiliary delay time Dsp occurs with respect to the output timing of the reproduced sound. Thus, the sound reproduced and output with a delay is synchronized with the reproduction output sound of the other audio reproducing apparatus at the same output timing. That is, it is possible to appropriately synchronize the audio reproduction output timing in correspondence with the actual delay time Dtp that exceeds the maximum delay possible time Dtmax of the other audio reproduction device 12 (13) itself.

On the other hand, if a negative determination result is obtained in step S402, the procedure after step S405 is executed.
If a negative determination result is obtained in step S402, the delay corresponding to the actual delay time Dtp calculated in step S401 can be dealt with only by internal delay processing, and the assistance of the server 11 is not necessary. It will be. Therefore, in step S405, the delay time information held in the delay time setting processing unit 32 is updated so that the actual delay time Dtp becomes the set delay time Dtp1.
In the next step S406, whether the relationship between the actual delay time Dtp obtained in the previous delay time setting process and the maximum delay possible time Dtmax is Dtp> Dtmax, that is, an affirmative result in step S402. It is determined whether or not this has occurred. The case where an affirmative determination result is obtained in step S406 means that the actual delay time Dtp is less than or equal to the maximum delay possible time Dtmax from the state in which the delay time assistance by the server 11 was required in the previous delay time setting process. Thus, it is a case where the state is restored to the state where the delay time assistance is not required. Then, the server 11 at this time is in a state of executing processing for delay time assistance (delay of packet transmission timing) in response to step S404 executed at the time of the previous delay time setting processing. It will be. Therefore, depending on step S407, a delay time auxiliary cancellation request is transmitted to the server 11. In response to this request, the server 11 stops the delay control of the packet transmission timing as the auxiliary delay time that has been executed so far, and transmits the packet at the same timing as the packet transmission to the other audio playback device. To return to control.
If a negative determination result is obtained in step S406, the delay time assistance by the server 11 is not required even in the previous delay time setting process. The process of FIG. 8 is exited.

  In the procedure of FIG. 8, the server 11 sets the time length obtained by the actual delay time Dtp−the maximum delay delay time Dtmax as the auxiliary delay time Dsp to be covered. However, a predetermined time longer than this is set. The setting may be made according to a certain rule. In other words, as a result of integrating the internal delay control by the audio playback device 12 (13) and the delay by the server 11, a delay corresponding to the actual delay time Dtp is given to the reproduced and output sound. .

Further, the present invention is not limited to the configuration as the embodiment described so far.
For example, in the above-described embodiment, a configuration limited to only audio playback is shown, but a video playback device that plays back video content may be used instead of the audio playback device of the embodiment. That is, the present invention is applied to a playback apparatus that inputs video content data consisting of a video signal and an audio signal synchronized with the playback time, plays back the video signal by display, and plays back and outputs the audio signal as sound. Applicable. In this case, as in the description of the embodiment, for example, by synchronizing audio output from a plurality of video playback devices connected to the network, as a result, an image displayed by the video playback device is also output. Timing synchronization is obtained. Such a system in which video playback devices are connected to a network is useful when, for example, relatively large-scale event venues display images having the same contents on monitors arranged at various locations.

It is a figure which shows the structural example of the home network with which embodiment of this invention respond | corresponds. It is a figure which shows the structural example of the server with which the home network of embodiment is equipped. It is a figure which shows the structural example of the audio reproduction apparatus with which the home network of embodiment is equipped. It is a figure which shows typically the example of a process sequence for the audio | voice synchronous reproduction | regeneration performed by the audio reproduction apparatus of embodiment. It is a flowchart which shows the example of a process sequence for the audio content reception which the audio reproduction apparatus of embodiment performs. It is a flowchart which shows the example of a procedure of the audio | voice output process which the audio reproduction apparatus of embodiment performs. It is a flowchart which shows the example of a procedure of the delay time setting process about the reproduction | regeneration output audio | voice which the audio reproduction apparatus of embodiment performs. As another embodiment, an example of a processing procedure to be executed by the audio reproduction device in order to synchronize the reproduction output audio by using both the delay of the reproduction output audio by the audio reproduction device and the delay of the packet transmission timing by the server. FIG.

  DESCRIPTION OF SYMBOLS 1 Network line, 11 server, 12.13 audio | voice reproducing apparatus, 21 interface, 22A reproduction | regeneration data buffer, 22B reproduction | regeneration audio signal buffer, 23 signal processing part, 24 1st filter, 25 D / A converter, 26 amplifier, 27 Speaker output Terminal, 28 microphone terminal, 29 second filter, 30 A / D converter, 31 sound pickup buffer, 32 delay time setting processing unit, 33 delay time information holding unit, 34 control unit, 35 operation unit, 36 internal bus, 41 Interface, 42 storage unit, 43 control unit, 44 delay time information holding unit, 45 internal bus, M microphone

Claims (5)

Audio reproduction signal processing means for inputting an audio signal supplied from one audio signal output source and executing signal processing for reproducing and outputting as audio;
Collected sound signal of a microphone device provided so as to pick up ambient sound at a predetermined position determined according to the position where the sound source reproduced and output by the sound reproduction signal processing means is installed From other device output sound acquisition means for acquiring the audio signal component of the other device sound that is input to the other audio playback device from the audio signal output source and is being reproduced and output,
The audio reproduction signal processing means reproduces the audio having the reproduction audio content that is the same as the audio signal component of the other apparatus audio and the timing at which the audio signal component of the other apparatus audio is acquired by the other apparatus output audio acquisition means. A time difference detecting means for detecting a time difference from the output timing;
Reproduction output control means for controlling the sound reproduction signal processing means to change the timing at which the sound is reproduced and output based on the time difference detected by the time difference detection means;
An audio reproducing apparatus comprising: The other machine output voice acquisition means is
Under the state where the predetermined frequency band is attenuated for the sound reproduced and output by the audio reproduction signal processing means, by acquiring the collected sound signal only in the predetermined frequency band, The voice signal component of the other machine voice is acquired.
The sound reproducing apparatus according to claim 1, wherein The time difference detecting means is
The signal processing time corresponding to the predetermined signal processing path in the audio reproduction signal processing means, the timing of the audio signal input to the predetermined signal processing path in the audio reproduction signal processing means, and the same as this audio signal Based on the time difference from the timing at which the audio signal component of the other device audio having the reproduced audio content is acquired,
The audio reproduction signal processing means reproduces the audio having the reproduction audio content that is the same as the audio signal component of the other apparatus audio and the timing at which the audio signal component of the other apparatus audio is acquired by the other apparatus output audio acquisition means. The time difference from the output timing is detected.
The sound reproducing apparatus according to claim 1, wherein The time difference detecting means is
Collected sound signal of a microphone device provided so as to pick up ambient sound at a predetermined position determined according to the position where the sound source reproduced and output by the sound reproduction signal processing means is installed To obtain the audio signal component of the own sound reproduced and output by the audio reproduction signal processing means,
A timing at which an audio signal having the same playback sound content as the sound signal component of the own device sound is obtained in a predetermined signal processing stage of the sound reproduction signal processing means; and a timing at which the sound signal component of the own device sound is acquired. By calculating the time difference between
A signal processing time corresponding to a predetermined signal processing path in the sound reproduction signal processing means is obtained.
The sound reproducing apparatus according to claim 3. An audio reproduction signal processing procedure for inputting an audio signal supplied from one audio signal output source and executing signal processing for reproducing and outputting as audio;
Collected sound signal of a microphone device provided to pick up ambient sound at a predetermined position determined according to a position where a sound source to be reproduced and output by the sound reproduction signal processing procedure is installed From the other device output sound acquisition procedure for acquiring the sound signal component of the other device sound that is input from the audio signal supplied from the audio signal output source to the other sound playback device and is being reproduced and output,
The audio signal component of the other device's sound is acquired by the other device's output sound acquisition procedure, and the sound having the reproduced sound content that is the same as the sound signal component of the other device's sound is reproduced by the sound reproduction signal processing procedure. A time difference detection procedure for detecting a time difference from the output timing;
A reproduction output control procedure for controlling so as to change the timing at which audio is reproduced and output by the audio reproduction signal processing procedure based on the time difference detected by the time difference detection procedure;
A sound reproduction method characterized by executing

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