KR102482049B1 - Audio clock adjustment through buffer occupancy prediction in network based public address - Google Patents

Abstract

Disclosed is a method for audio clock adjustment in a network-based public address (PA). The disclosed method comprises: a step of buffering digital audio data to an audio buffer for a future withdrawal (the digital audio data of the specified amount for each pre-determined transmission cycle is transmitted through a network and is received by serial reception timing by a device); a step of calculating a plurality of prediction values of the amount of the digital audio data to be remaining in the audio buffer right before the following reception timing based on the comparison between serial reception timing; a step of setting a clock rate based on the plurality of prediction values; a step of generating an audio clock signal having the preset clock rate; and a step of providing digital audio data from the audio buffer in accordance with the audio clock signal. Therefore, clock signals can be generated in a cost-efficient manner.

Description

Audio clock adjustment through buffer occupancy prediction in network-based public address

This disclosure relates to audio clock adjustment in a network-based public address (PA), and more particularly, to audio clock adjustment through buffer occupancy prediction in a network-based PA.

Public Address (PA) systems are installed in environments such as buildings or complexes, such as apartment complexes, schools, government offices, large buildings, airports, shopping malls, etc. It is configured to transmit the sound of (eg, guide voice, background music, etc.). Occasionally, these systems are also equipped with the ability to make emergency broadcasts announcing emergency situations occurring in or around the environment in which they are installed (eg, fires, explosions, flooding, power outages, earthquakes, etc.). For such public address broadcasting, various devices are installed for each desired region (eg, company branch).

Recently, many examples of PA systems have been implemented on a large scale, such as by connecting several regional facilities to a network, as disclosed in Korean Patent Registration No. 10-1698979 (published date: January 24, 2017). In such a PA system, since audio data for the PA may not be received at a uniform rate at the receiving side through the network, latency may occur at the receiving side.

Audio clock coordination in network-based public address is disclosed herein.

In an example, a device for audio clock adjustment in a network-based public address (PA) includes an audio buffer in which digital audio data is buffered for later retrieval (the digital audio data is stored in a specific Calculate a plurality of predicted values of the amount that the digital audio data will remain in the audio buffer immediately before the subsequent reception timing, based on the comparison between the amount transmitted over the network and received by the device at successive reception timings and the successive reception timings and an audio clock adjustment unit that sets a clock rate based on a plurality of predicted values and generates an audio clock signal having the set clock rate, and provides digital audio data from an audio buffer according to the audio clock signal. It includes an audio data formatting unit that does.

The foregoing summary is provided to introduce some aspects in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to delineate the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that provide any or all of the advantages discussed herein.

According to the present disclosure, by buffering audio data received through a network and then outputting audio data according to an audio clock signal having a variable clock rate, discarding data due to excessive buffering and insufficient buffering It is possible to prevent loss of original audio data, such as insertion of data caused by the error, and suppress the occurrence of latency.

According to the present disclosure, by monitoring the reception timing of data buffered through a network, the actual reception timing can be recognized and the audio clock rate can be variably adjusted accordingly, so that transmission such as Precision Time Protocol (PTP) A clock signal for the output of audio data can be generated in a cost-effective manner with less complex hardware design, without the need for a network switch supporting the protocol.

1 shows an example of audio communication for Public Address (PA) in a networked environment.
FIG. 2 is a block diagram showing an example of a network-based PA system in which the network-based PA receiver of FIG. 1 is implemented.
3 is a block diagram showing an example of the local PA subsystem of FIG. 2;
4 is a block diagram showing an example of the network-based PA receiver of FIG. 1;
5 is a flow diagram showing an example of a process for performing audio clock adjustment through buffer occupancy prediction in a network-based PA.

Various terms used in the present disclosure are selected from the terminology of common terms in consideration of functions in this document, which may be recognized differently according to the intention of those skilled in the art, conventions, or the emergence of new technologies. In certain instances, some terms may be given meanings as set forth in the Detailed Description. Therefore, the terms used in this document should be defined consistently with the meanings of the terms in the context of the present disclosure, not simply by their names.

In this document, the terms "comprise", "have", etc. are used when specifying the presence of elements listed below, such as certain features, numbers, steps, operations, components, information, or combinations thereof. Unless otherwise indicated, these terms and variations thereof are not intended to exclude the presence or addition of other elements.

As used herein, the terms "first", "second", etc. are intended to identify several resembling elements. Unless otherwise stated, such terms are not intended to impose limitations on these elements or on the specific order of their use, but are merely used to refer to several elements separately. For example, an element may be referred to by the term "first" in one example, while the same element may be referred to by a different ordinal number, such as "second" or "third" in another example. In such instances, these terms are not intended to limit the scope of this disclosure. Further, use of the term “and/or” in a list of multiple elements includes all possible combinations of any one or more of the listed items, including any one or more of these items. Further, expressions in the singular form include the meanings in the plural form unless the context clearly dictates otherwise.

Certain examples of the present disclosure will now be described in detail with reference to the accompanying drawings. However, this disclosure may be embodied in many different forms and should not be construed as being limited to the examples set out in this document. Rather, these examples are given to provide a better understanding of the scope of the present disclosure.

1 shows an example of audio communication for Public Address (PA) in a networked environment.

In the illustrated example, network-based PA transmitter 105 transmits audio data to network-based PA receiver 110 over network 108 . In some example implementations, the network-based PA transmitter 105 transmits digital audio data at a given sample rate and at a given bit depth using a given data transmission method, e.g., multicast. In this way, it is possible to transmit with a predetermined transmission period. The network-based PA receiver 110 may receive such digital audio data, for example, by joining a multicast group. In addition, the network-based PA receiver 110 writes the received audio data into a buffer (eg, First-In-First-Out (FIFO) buffer) and reads the buffered audio data to variably It may be provided according to a clock signal having a set clock rate. In this way, the network-based PA receiver 110 is able to reduce the latency that may occur in the network-based PA receiver 110 even if, under certain circumstances in the network 108, audio data does not enter the network-based PA receiver 110 in its transmission period. can reduce

As an example, the network-based PA transmitter 105 may transmit stereo channel audio data to the network-based PA receiver 110 via the network 108 every predetermined transmission period of 1 ms. For example, this audio data may have a sample rate of 48 kHz and a bit depth of 24 bits for each of the left and right channels, so (1/1000)×2×48×1000×24 = 2304 bits (i.e. 288 bytes). The network-based PA receiver 110 may receive stereo channel audio data and buffer it in a buffer, e.g., with a non-Operating System (non-OS) design and eventually with some device driver. ) is also not used, and buffering can be done periodically in the buffer. When audio data is accumulated in the buffer to some extent, the network-based PA receiver 110 may output it in a predetermined internal interface format, for example, an Inter-IC Sound (I ² S) interface format. In order to maintain the amount of audio data remaining in the buffer or the buffer occupancy level representing it without significant fluctuation, the network-based PA receiver 110 may adjust the rate of a clock signal for outputting audio data. For example, this clock rate is a reference rate (which is, for example, the sample rate of audio data per channel in the case of providing output audio data of 32 bits wide for each channel according to the I ² S interface format 48 kHz 2 × 48 × 1000 × 32 = 3.072 × 10 ⁶ bits per second, i.e., determined as a bitrate of 3.072 MHz) based on the current buffer occupancy level around the reference rate based on can be regulated.

In a particular example, network 108 may be an Internet Protocol (IP) based network. Additionally, the network-based PA transmitter 105 and the network-based PA receiver 110 may not involve a network switch that supports the Precision Time Protocol (PTP) used for clock synchronization on the network 108. Bar, network 108 may be a non-PTP network.

2 is a block diagram showing an example of a network-based PA system 200 in which a network-based PA receiver 110 is implemented. The network-based PA system 200 may be implemented in a target environment (e.g., a complex comprising several buildings, a collection of local offices distributed in several remote locations, the interior of at least a portion of a building, an architectural structure, or the like). and/or outdoor environments). For example, the target environment may be divided into multiple zones, and performing PA through the PA system 200 may include notifying the same or different messages across several zones. An example implementation of network-based PA system 200 is discussed in more detail below.

In the illustrated example, the network-based PA system 200 includes at least one local PA subsystem 210-1, 210-2, ..., 210-k (which are hereinafter individually or collectively referenced " 210"). For example, each local PA subsystem 210 may be constructed or installed within a corresponding area (eg, per desired area or building) to enable a PA in a corresponding area within the target environment. Referring to FIG. 3 , example implementations of each local PA subsystem 210 will be described below.

In the example of FIG. 2 , local PA subsystem 210 is communicatively coupled with an external entity (e.g., other local PA subsystems 210 of network-based PA system 200) via network 280 ( communicatively coupled). Examples of networks 280 include the Internet, a wide area network (WAN), a metropolitan area network (MAN), a local area network (LAN), and the like.

As shown in FIG. 2 , network-based PA system 200 may further include a management subsystem 220 . Management subsystem 220 may be communicatively coupled with local PA subsystem 210 via network 280 . Management subsystem 220 may include a computing device operable to receive and process input from a user (eg, an administrator of network-based PA system 200), and to provide output representing certain information. For example, a memory of such a computing device may store program code that, when executed by a processor, provides a graphical user interface (GUI). The GUI may be displayed on a display device coupled to the computing device, for example, allowing a user to view at least a portion of the network-based PA system 200 (e.g., the local PA subsystem 210-1, 210-2, ..., 210-k), a control GUI that assists the user in controlling at least a part of the network-based PA system 200 (e.g., a part of the network-based PA system 200) may include a schematic GUI and/or other GUIs to assist in monitoring the local PA subsystem (specific device within one of 210-1, 210-2, ..., 210-k).

Additionally, in some example implementations, local PA subsystem 210 may be communicatively coupled to external service system 270 via network 280 . For example, the external service system 270 may include a platform operated by a provider or operator of the network-based PA system 200 or by a third party. The platform (e.g., based on a cloud computing system) provides PA-related services (e.g., audio streaming service, PA status/flow monitoring service, failover/remote monitoring service, system management service, and/or other service) can be provided.

3 is a block diagram showing an example of a local PA subsystem 210 .

In the example of FIG. 3 , the local PA subsystem 210 includes a control device 310, a source device 320, an amplifier 330, a relay device 340 and speakers 350-1, 350-2, ... , 350-m) (which may be individually or collectively referred to below by the reference number “350”).

In the illustrated example, certain of the components of local PA subsystem 210 (e.g., components 310, 320, 330, 340, 350) are communicatively coupled to other components within local PA subsystem 210. . Examples of such communication between devices within the local PA subsystem 210 include communication over a network such as a LAN local to the area where the local PA subsystem 210 is installed, digital serial communication, communication over contact lines, and various other analog or Including digital communication.

In the illustrated example, certain of the components (e.g., components 310, 320, 330, 340, and 350) of the local PA subsystem 210 are communicated via the network 280 to an external entity (e.g., network-based PA system 200). ) of the other local PA subsystem 210 (which may be referred to below by reference number “210′”, and its components, e.g., control device 310 and source device 320, also reference number “310”, respectively, below). (which may be referred to as '" and "320'"). For example, the control device 310 of the local PA subsystem 210 may be in communication over the network 280. In some cases, other specific components within the local PA subsystem 210 communicate with and/or bypass the controlling device 310, other local PA subsystems of the network-based PA system 200. 210' (eg, the controlling device 310' of the local PA subsystem 210').

In the illustrated example, the local PA subsystem 210 is operable under control by the control device 310 . To this end, the control device 310 is controlled according to control from inside or outside the local PA subsystem 210 to which it belongs (eg, the management subsystem 220 as shown in FIG. 2 or a computing device included therein). and can provide control signals. For example, the controlling device 310 may be configured from a sensing device coupled with the controlling device 310 (eg, a microphone, camera, or other type of sensor) or other local PA of the network-based PA system 200. A control signal may be provided according to a signal input to the control device 310 from the subsystem 210 'or the management subsystem 220 (eg, a computing device providing a control GUI in the management subsystem 220) , For example, an input signal may be used as a control signal, or a control signal may be generated and output based on the input signal. Such control signals may be used to control the local PA subsystem 210 to which the controlling device 310 belongs (eg, a specific device within the local PA subsystem 210), or other parts of the network-based PA system 200. Provided therein for control of the local PA subsystem 210' (eg, a specific device within the local PA subsystem 210').

In some example implementations, a controlling device 310 disposed within the local PA subsystem 210 may perform the following actions: send an audio signal for the PA to another device disposed within the local PA subsystem 210. (e.g., source device 320) and/or receive over network 280 from other local PA subsystems 210' (e.g., specific devices therein) of network-based PA system 200; Provides the received audio signal to another device (e.g., amplifier 330, relay device 340, or some type of additional device) disposed within the local PA subsystem 210 and/or to a network-based PA system ( 200) to transmit over network 280 to other local PA subsystems 210' (eg, specific devices within it); To a given device (e.g., relay device 340) disposed within the local PA subsystem 210, such an audio signal is sent to a specific speaker (e.g., relay device 340) within that local PA subsystem 210 for playback. providing a control signal to be transmitted to at least some of the speakers 350-1, 350-2, ..., 350-m coupled to; and/or the like.

In the illustrated example, source device 320 is the device from which an audio signal in a certain format is derived. For example, the source device 320 may be a sound player (eg, a compact disc player (CDP), MP3 player, FM/AM radio tuner, internet streaming receiver, cassette deck, other sound player, etc.), text-to-speech (Text-To-Speech: TTS) synthesizer, a microphone (eg, Remote Microphone (RM)), and the like. As described above, audio signals from source device 320 of local PA subsystem 210 may be provided to control device 310 of that local PA subsystem 210, then over network 280. Other local PA subsystems 210' (eg, the controlling device 310' of the local PA subsystem 210') may also be provided.

In the illustrated example, the relay device 340 is a line (in this document referred to as " may be referred to as an "audio line"). Thus, the relay device 340 can receive an audio signal through such an audio line. For example, an audio signal provided from the control device 310 may be input to the relay device 340 . Such audio signals may be internal (e.g., source device 320) or external (e.g., other local PA subsystems 210' of network-based PA system 200) of local PA subsystem 210 to which relay device 340 belongs. ) in the source device 320', external service system 270, etc.). In some exemplary implementations, the input audio signal of the relay device 340 is passed through a corresponding amplifier 330 interposed between the relay device 340 and the control device 310 so that the audio signal output from the control device 310 After being amplified, it may be provided to the relay device 340 through a corresponding audio line. For example, the control device 310 may output a line level (eg, about 1V) audio signal to an audio line connected between the control device 310 and the amplifier 330, and the amplifier 330 may output the audio signal of the control device 310 to the amplifier 330. An audio signal output from 310 may be received, amplified to a speaker level (eg, about 100V), and then output to an audio line connected between the amplifier 330 and the relay device 340 . In some other exemplary implementations, the output audio signal of control device 310 may be provided to relay device 340 via a corresponding audio line without going through amplifier 330 .

Also, in the illustrated example, the relay device 340 may relay the received audio signal to at least one of the speakers 350-1, 350-2, ..., 350-m coupled therewith. The relay of audio signals to each speaker 350 may be enabled or disabled according to a control signal provided from the control device 310 to the relay device 340 . For example, in response to receiving a specific control signal from the control device 310, the relay device 340 transmits, for example, one of several input audio signals of the relay device 340 to the relay device 340 according to the received control signal. ), relaying to at least one of the speakers 350-1, 350-2, ..., 350-m coupled to the speaker may be enabled or disabled. Then, when an input audio signal is relayed to the speaker 350, the speaker 350 may be driven to emit sound according to the audio signal.

In some example implementations, this audio signal relay control can be considered to involve on/off control of a contact corresponding to a channel between an input audio signal and a given speaker 350 . For example, 16 speakers corresponding to 16 channels may be coupled to the relay device 340, and the relay device 340 may receive one or more input audio signals and reproduce them to each of the 16 speakers. relaying of one of the input audio signals to the input may be enabled or disabled based on the control signal (ie, the contact for each channel may be turned on or off depending on the control signal). In such an example, the relay device 340 transmits a control signal for controlling the audio signal relay through a line connected between the control device 310 and the relay device 340 (which is, for example, a contact line that is a line separate from the audio line). It can be received from the control device 310 through).

2 and 3, the network-based PA receiver 110 is disposed in the local PA subsystem 210 of the network-based PA system 200, and the control device 310 of the local PA subsystem 210 exemplified by inclusion. Also, although not shown, the network-based PA transmitter 105 may be deployed in the network-based PA system 200, e.g., local PA subsystems 210-1, 210-2, ..., 210-k. ) may be included in the source device 320 of a particular one.

4 is a block diagram showing an example of a network-based PA receiver 110.

In the example of FIG. 4 , the network-based PA receiver 110 includes an audio data receiver 410 , an audio buffer 420 , an audio clock adjuster 440 and an audio data formatter 450 . Other example implementations of network-based PA receivers 110 are also contemplated. For example, the network-based PA receiver 110 may also include additional components not shown and/or may include some but not all of the components listed with respect to FIG. 4 .

In the illustrated example, the audio data receiver 410 includes an external interface 415 . For example, external interface 415 may be a modem, Ethernet interface, Network Interface Card (NIC), or the like, and may be a network (e.g., network 280) from network-based PA transmitter 105. )) to receive digital audio data (eg, a stereo channel audio data sample). As described above, digital audio data can be transmitted over the network in a specific amount at each predetermined transmission period and received by the external interface 415 at successive reception timings. A delay or advance may occur in the reception of such a particular amount of digital audio data. Delayed reception may indicate that the length of time between two consecutive reception timings is greater than a predetermined transmission period (eg, by a value over some value), and delayed reception may indicate that the length of time between two consecutive reception timings is greater than a predetermined transmission period (eg, by a value over some value). For example, by a value exceeding a certain value). Reception in which neither delay nor pre-set occurs can be called normal.

In the illustrated example, received digital audio data is buffered in audio buffer 420 for later retrieval. For example, audio buffer 420 may be a circular FIFO buffer or another type of FIFO buffer.

In the illustrated example, the audio clock adjusting unit 440 generates an audio clock signal having a specific clock rate. For example, the audio clock signal generated by the audio clock controller 440 may include a bit clock pulse having a high level part and a low level part.

In the illustrated example, the audio clock control unit 440 variably sets a clock rate and generates an audio clock signal having the set clock rate. To this end, the audio clock adjustment unit 440 determines the amount of digital audio data remaining in the audio buffer 420 immediately before the next reception timing, based on a comparison between successive reception timings at which the aforementioned specific amount of digital audio data is received. can predict By way of example, a comparison between the timing of successive receptions may include determining if such reception is normal or if there is a delay or early delay in such reception. If it is determined that there is a reception delay or an early reception, the audio clock adjusting unit 440 can predict the amount of digital audio data remaining in the audio buffer 420 immediately before the next reception timing. If it is determined that the reception is normal, without or with such prediction, the audio clock adjusting unit 440 adaptively adjusts the amount of digital audio data remaining in the audio buffer 420 as close as possible to the predetermined reference amount. You can set the clock rate. For example, if stereo channel audio data having a 48 kHz sample rate and 24 sample bits for each channel is transmitted from the network-based PA transmitter 105 as described above and the predetermined period of such transmission is 1 ms, the network-based PA The receiver 110 may wish to keep at least the following reference amount of audio data in the audio buffer 420 as much as possible to prevent the PA from being disconnected: (1.5/1000) x 2 x 48 x 1000 x 24 = 3456 bits (i.e. 432 bytes), the amount of audio data expected to be received. Then, the audio clock adjusting unit 440 may set the clock rate according to the difference between the amount of remaining audio data in the audio buffer 420 and the reference amount (eg, using an adaptive filter).

In some example implementations, if the amount of digital audio data to remain in the audio buffer 420 immediately prior to the timing of subsequent reception is predicted, the audio clock adjustment unit 440 adjusts the clock rate of the audio clock signal to be generated based on the predicted amount. so that it can be set to one of a plurality of possible clock rates. For example, audio clock adjustment unit 440 may set a clock divisor based on such prediction, which may be used as follows: Finite State Machine of network-based PA receiver 110 : FSM) clock generation unit (not shown) generates an FSM clock signal having a specific FSM clock frequency (eg, 150 MHz or 450 MHz), while the audio clock adjustment unit 440 divides the FSM clock frequency by the set clock divisor and An audio clock signal having the same clock rate is generated from the FSM clock signal. In particular, the audio clock adjustment unit 440 sets the clock divisor to one of a plurality of integers greater than 1 and determined for a given sample rate of digital audio data (eg, a predefined sample rate such as 48 kHz, 44.1 kHz, 32 kHz or 16 kHz). can be set For example, the clock divisor is a number of (e.g., five or six) candidate divisors, each being an integer greater than 1, determined based on the reference rate (which depends on the sample rate of the digital audio data) and the FSM clock frequency. can be one of Table 1 shows six candidate divisors and six corresponding possible clock rates in the case where the FSM clock frequency is set to 150 MHz and outputs stereo channel digital audio data with a sample rate of 48 kHz and a width of 32 bits for each channel. foreshadow

In Table 1, the reference rate is 2 × 48 × 1000 × 32 = 3.072 MHz as described above.

As can be seen in Table 1, these six possible clock rates are the FSM clock frequency divided by a divisor of 46 to 51, and have values around the reference rate. Any two of these possible clock rates can be said to have the following relationship: the larger of these two clock rates corresponds to the candidate divisor a and the smaller of these two clock rates corresponds to the candidate divisor a+x , the large clock rate is x orders of magnitude faster than the small clock rate, in other words, the small clock rate is x orders of magnitude slower than the larger clock rate.

In some example implementations, the audio clock adjustment unit 440 may set the clock divisor lower as the predicted value of the amount of digital audio data remaining in the audio buffer 420 at a subsequent reception timing increases. For example, when it is predicted that more digital audio data will remain in the audio buffer 420 at the preset clock rate, the audio clock adjuster 440 sets a smaller clock divisor, that is, a higher clock rate. By generating an audio clock signal of , the remaining data in the audio buffer 420 can be read more quickly. If it is predicted that less digital audio data will remain in the audio buffer 420 at the next reception timing at the preset clock rate, the audio clock adjusting unit 440 sets a large clock divisor so that the remaining data in the audio buffer 420 can be read more slowly.

In the illustrated example, the audio data formatting unit 450 fetches digital audio data from the audio buffer 420 and provides it through the internal interface 455 according to the audio clock signal generated by the audio clock adjusting unit 440. . In some example implementations, internal interface 455 may be an I ² S interface, another serial bus interface for audio data transmission, or another type of interface, and audio data formatter 450 converts the fetched digital audio data to It can be output according to the audio clock signal in a specific format suitable for the internal interface 455. For example, the audio data formatting unit 450 may format the fetched digital audio data to conform to the internal interface 455, and convert one bit of the formatted digital audio data to each bit clock pulse of the audio clock signal. can provide

5 is a flow diagram showing an example of a process 500 for performing audio clock adjustment through buffer occupancy prediction in a network-based PA. For example, process 1000 of FIG. 10 may be performed by network-based PA receiver 110 (eg, audio clock adjustment unit 440 and audio data formatter unit 450). Other example flows of process 500 are also contemplated. For example, process 500 may include additional operations not shown in FIG. 5 , may include some but not all of the operations listed with respect to FIG. 5 , and/or may include It may be performed in an order different from the order shown.

At operation 510, the digital audio data is buffered in an audio buffer for later retrieval. The digital audio data may be samples transmitted through a network (eg, an IP-based non-PTP network) by a specific amount at each predetermined transmission period and received at successive reception timings by the network-based PA receiver 110.

In operation 520, based on the comparison between successive receive timings, a plurality of predicted values of the amount of digital audio data will remain in the audio buffer immediately prior to the subsequent receive timing are calculated.

In some example implementations, the network-based PA receiver 110 (e.g., audio clock adjustment unit 440) performs a comparison between successive receive timings (e.g., comparing a current receive timing to a previous receive timing to determine a length of time between them). ), it is possible to determine whether reception of a specific amount of digital audio data transmitted per predetermined transmission period is normal, or whether there is a delay or early delay in such reception.

In some example implementations, the network-based PA receiver 110 (e.g., audio clock adjustment 440) may continuously make these determinations over a period of time to obtain statistical data such as: a value indicating how many times n receive delays have occurred (which may be denoted herein as delay(n), where n is a positive integer within any desired range); and/or a value indicating how many consecutive n reception preconditions have occurred. Accordingly, the network-based PA receiver 110 (eg, audio clock adjustment unit 440) may calculate other values from such statistical data. For example, a value delay(n, n+1, ...) indicating how many times n or more consecutive reception delays have occurred may be calculated as delay(n) + delay(n+1) + ....

In some example implementations, the network-based PA receiver 110 (e.g., audio clock adjustment unit 440) may obtain the following statistical data by continuously making the above-described comparisons and decisions over a predetermined period of time. :

- a value representing the time taken on average for the reception of the above-mentioned specific amount of digital audio data (which may be referred to herein as TIME _Average );

- at least one value indicative of the time taken for reception of said particular quantity of digital audio data if there is a delay, e.g. if the worst delay for reception of said particular quantity of digital audio data is A value representing the time taken for such reception, if any (which may be denoted herein as TIME _{Delay_Worst} ) and/or the average delay in the reception of the above-mentioned specific amount of digital audio data, if any. A value indicating how long it takes to receive (this may be referred to as TIME _{Delay_Average} in this document), and/or

- a value indicative of the time taken for such reception in case there is an advance in the reception of the above-mentioned specific amount of digital audio data, e.g. in case of the worst advance in the reception of the above-mentioned specific amount of digital audio data A value representing the time taken for such reception (which may be denoted herein as TIME _{Advance_Worst} ) and/or the average advance of the reception of the aforementioned specified amount of digital audio data. A value representing time (this may be referred to as TIME _{Advance_Average} in this document).

In some example implementations, the network-based PA receiver 110 (e.g., audio clock adjustment unit 440) predicts the length of time from a current reception timing to a subsequent reception timing during successive reception timings in a plurality of predictive manners to obtain multiple reception timings. time value can be calculated. For example, the prediction of the value of the reception time may be performed in a statistical manner, for example, based on the statistical data TIME _Average , TIME _{Delay_Worst} , TIME _{Delay_Average} , TIME _{Advance_Worst} and/or TIME _{Advance_Average} described above. For example, multiple receive time values may include:

- a first reception time value representing the time expected to take on average for the reception of the specified above-mentioned amount of digital audio data, which may be given, for example, as TIME _Average ;

- at least one second reception time value indicative of the expected time taken for reception of the above-mentioned specific amount of digital audio data, if there is a delay, which may be given, for example, as TIME _{Delay_Worst} and/or TIME _{Delay_Average} may, and/or

- at least one third reception time value indicative of the time expected to take the reception of a particular above-mentioned amount of digital audio data, in case there is an early reception, which may be given, for example, as TIME _{Advance_Worst} and/or TIME _{Advance_Average} can

In some example implementations, the network-based PA receiver 110 (e.g., audio clock adjustment unit 440) may each predict a plurality of values of the amount of digital audio data to remain in the audio buffer immediately prior to the timing of subsequent reception in a plurality of different ways. For example, it may be calculated based on a respective corresponding one of a plurality of reception time values, a preset clock rate, and an amount of digital audio data currently remaining in the audio buffer. For example, the plurality of predicted values of the amount of digital audio data to remain in the audio buffer immediately before the next reception timing may include (where the preset clock rate is CLK _PRESET , and the digital audio data in the audio buffer The amount currently remaining is denoted as BUF _CURR ):

,-

,

,-

,

,-

,

, 그리고/또는-

, and/or

.-

.

In operation 530, a clock rate is set based on the plurality of predicted values of the amount of digital audio data that will remain in the audio buffer immediately prior to a subsequent reception timing, and an audio clock signal having the set clock rate is generated. For example, prediction-based clock rate setting may be performed when reception delay or early reception occurs, and when reception is normal, adaptive clock rate setting may be performed as described above.

In some example implementations, the network-based PA receiver 110 (e.g., the audio clock adjustment unit 440) determines which of a plurality of predefined setting methods to set the clock rate based on the predicted value, and the corresponding You can set the clock rate by setting method. An example of a predefined setting method is a method of setting the clock rate based on a specific one of a plurality of predicted values, a method of setting the clock rate based on a probability that a delay will occur subsequent to a delay currently occurring in receiving a specific amount of digital audio data manner, setting the clock rate to a predefined minimum clock rate, and the like.

In some example implementations, the plurality of prediction values may include BUF _{PRED1 ,} BUF _PRED2a , BUF _PRED2b , BUF _PRED3a and BUF _PRED3b , and the network-based PA receiver 110 (e.g., audio clock adjuster 440) may It is possible to determine whether each predicted value of exceeds a reference value (eg, 0). For example, as illustrated in Table 2, according to whether each predicted value exceeds 0 (indicated by "+") or not (indicated by "-"), the first to fifth setting methods Either one may be applied.

This takes into account that as the delay in reception increases, the amount predicted to remain in the audio buffer increases, and as delay in reception increases, the amount predicted to remain in the audio buffer decreases.

In some example implementations, setting the clock rate in the first setting manner can include setting the clock rate based on the predicted value BUF _PRED1 . For example, the clock rate can be set as follows:

- if the prediction value BUF _PRED1 is within the first predefined range, the clock rate is set to the preset clock rate CLK _PRESET ;

- if the predicted value BUF _PRED1 is within a second predefined range covering the first predefined range and has a value greater than any value in the first predefined range, the clock rate is the preset clock rate CLK _PRESET set to a higher clock rate (eg, clock rate 1 step faster than clock rate CLK _PRESET );

- if the predicted value BUF _PRED1 is within a second predefined range covering the first predefined range and has a value smaller than any value in the first predefined range, the clock rate is the preset clock rate CLK _PRESET set to a lower clock rate (eg, a clock rate that is one step slower than the preset clock rate CLK _PRESET );

- if the predicted value BUF _PRED1 has a value greater than any value in the second predefined range, the clock rate is higher than the preset clock rate CLK _PRESET (eg, by one step higher than the preset clock rate CLK _PRESET ) set to fast clock rate); and/or

- if the predicted value BUF _PRED1 has a value smaller than any value in the second predefined range, the clock rate is lower than the preset clock rate CLK _PRESET (eg, by one step lower than the preset clock rate CLK _PRESET ) slow clock rate), but, for example, as a newly set low clock rate instead of the preset clock rate CLK _PRESET , if the value obtained by recalculating the predicted value BUF _PRED1 is outside the second predefined range, the clock rate is a lower clock rate (e.g., at a clock rate that is two steps slower than the preset clock rate CLK _PRESET ), otherwise the clock rate is maintained (e.g., at a clock rate that is one step slower than the preset clock rate CLK _PRESET ).

In some example implementations, setting the clock rate with the second setting method can include setting the clock rate based on the predicted value BUF _PRED2b . For example, the clock rate can be set as follows:

- the clock rate is set to a clock rate lower than the preset clock rate CLK _PRESET (eg, a clock rate slower than the preset clock rate CLK _PRESET by 1 step); next

- If the value obtained by recalculating the predicted value BUF _PRED2b as a newly set low clock rate instead of the preset clock rate CLK _PRESET is greater than the reference value (eg, 0), the clock rate is (eg, slower than the preset clock rate CLK _PRESET by 1 step) clock rate), otherwise set again to a lower clock rate (eg, a clock rate two steps slower than the preset clock rate CLK _PRESET ).

In some example implementations, setting the clock rate with the third setting method can include setting the clock rate based on the predicted value BUF _PRED2a . For example, the clock rate can be set as follows:

- the clock rate is set to a clock rate lower than the preset clock rate CLK _PRESET (eg, a clock rate slower than the preset clock rate CLK _PRESET by 2 steps); next

- If the value obtained by recalculating the predicted value BUF _PRED2a with a newly set low clock rate instead of the preset clock rate CLK _PRESET is greater than the reference value (eg, 0), the clock rate is (eg, 2 steps slower than the preset clock rate CLK _PRESET clock rate) is maintained, otherwise the clock fine-tuning described below is performed.

In some example implementations, setting the clock rate with the fourth setting method may include performing clock fine-tuning as follows. First, how many consecutive reception delays have occurred up to the currently occurring delay in reception of the above-mentioned specific amount of digital audio data (this can be referred to as the current delay continuation level, e.g., if the current delay following normal reception occurs, If a current delay occurs in succession of two reception delays and if a current delay occurs in succession to two consecutive reception delays, current delay continuation levels are 0, 1, and 2, respectively) may be checked. Subsequently, the probability that a delay occurs following the current delay may be calculated according to the following equation.

Then, a value of CLK _down that satisfies the condition that the following expression is greater than a reference value (eg, 0) may be searched for among several possible clock rate values.

Thereafter, the largest among the searched CLK _down values may be set as the clock rate. Additionally, depending on the current delay continuation level, the clock rate can be adjusted. For example, if the current delay continuation level is 2 or less, the clock rate can be set to a clock rate that is 2 steps faster than the currently set value, and if the current delay continuation level is 3 or 4, the clock rate is set to a clock rate that is 1 step faster than the currently set value. rate, and if the current delay sequence level is 5 or more, the clock rate may be maintained at the currently set value.

In some example implementations, setting the clock rate in a fifth setting way is setting the clock rate to a predefined lowest clock rate, e.g., among a plurality of possible clock rates (e.g., the six clock rates in Table 1). This may include setting it to the smallest.

At operation 540, digital audio data is fetched from the audio buffer and provided according to the audio clock signal. For example, the network-based PA receiver 110 (eg, the audio data formatting unit 450) fetches digital audio data from an audio buffer and synchronizes the fetched digital audio data with an audio clock signal to obtain a specific format ( For example, a format conforming to the I ² S protocol) may be provided.

The following are various examples of audio clock adjustment in network-based PAs.

In Example 1, a device for audio clock adjustment in a network-based public address (PA) includes: an audio buffer in which digital audio data is buffered for later retrieval (where the digital audio data is transmitted over the network by a specific amount every predetermined transmission period and received by the device at successive reception timings); Based on the comparison between the successive reception timings, calculating a plurality of predicted values of an amount of the digital audio data to remain in the audio buffer immediately before the subsequent reception timing, and setting a clock rate based on the plurality of prediction values; an audio clock adjusting unit generating an audio clock signal having the set clock rate; and an audio data formatting unit providing the digital audio data according to the audio clock signal generated from the audio buffer.

Example 2 includes the subject matter of Example 1, wherein the comparison includes determining whether reception of the above specific amount is normal or whether there is a delay or advance in reception of the above specific amount.

Example 3 includes the subject matter of Example 1 or Example 2, wherein setting the clock rate based on the plurality of predicted values sets the clock rate by any one of a plurality of setting methods based on the plurality of predicted values. Including determining whether to set, the plurality of setting methods is a method of setting the clock rate based on a specific one of the plurality of predicted values, the probability of delay occurring in succession to the delay currently occurring in the reception of the specific amount or a method of setting the above clock rate to a predefined minimum clock rate.

Example 4 includes the subject matter of any of Examples 1 to 3, wherein calculating the plurality of predicted values comprises, based on the comparison, a time length from a current reception timing among the consecutive reception timings to the subsequent reception timing. predicting by a plurality of prediction methods to calculate a plurality of reception time values, and corresponding to each of the plurality of prediction values among the plurality of reception time values, a preset clock rate, and the digital audio data in the audio buffer This includes calculating based on the amount currently remaining.

Example 5 includes the subject matter of Example 4, wherein each predicted value is the product of the corresponding receive time value multiplied by the preset clock rate minus the current remaining amount.

Example 6 includes the subject matter of Examples 4 or 5, wherein the plurality of reception time values include: a first reception time value representing an estimated amount of time expected to take on average for reception of the particular amount; at least one second reception time value representing the expected time it will take for reception above the particular amount if there is a delay in , or, if there is an early delay in reception above the particular amount, how long it will take for reception above the particular amount and one or more of at least one third reception time value representing a time predicted to be received.

Example 7 includes the subject matter of Example 6, wherein the at least one second time value is a time value representing a predicted time to take for reception of the particular amount if there is a worst-case delay for reception of the particular amount. or a time value representing an expected time taken for reception of the specific amount if there is an average delay in reception of the specific amount.

Example 8 includes the subject matter of Examples 6 or 7, wherein the at least one third time value is a predicted time that would take the reception of the particular amount of the above given that there is an average delay to the reception of the particular amount of the above. It includes at least one of a time value indicating or a time value indicating a time value that is predicted to take for reception of the particular amount if there is a worst-case premise on reception of the particular amount.

Example 9 includes the subject matter of Example 6, wherein setting the clock rate based on the plurality of predicted values comprises determining to set the clock rate in a first setting manner based on the plurality of predicted values. The plurality of reception time values include the first reception time value, the first reception time value corresponds to the first prediction value of the plurality of prediction values, and the clock rate according to the first setting method Setting includes setting the clock rate based on the first predicted value.

Example 10 includes the subject matter of Example 9, wherein setting the clock rate based on the first prediction value comprises: if the first prediction value is within a first range, setting the clock rate to the preset clock rate setting to, and if the first predicted value is within a second range covering the first range and greater than the first range, setting the clock rate to a higher clock rate than the preset clock rate; If the first prediction value is within the second range and smaller than the first range, setting the clock rate to a clock rate lower than the preset clock rate, and if the first prediction value is within the second range outside the above second range and greater than the above second range, setting the above clock rate to a clock rate higher than the above preset clock rate, and if the above first prediction value is outside the above second range and less than the above second range, the above and setting the clock rate to a clock rate lower than the preset clock rate.

Example 11 includes the subject matter of Example 10, wherein setting the clock rate to a clock rate lower than the preset clock rate comprises: recalculating the first predicted value with the lower clock rate instead of the preset clock rate; , setting the clock rate to another clock rate lower than the lower clock rate when the recalculated first prediction value is outside the second range.

Example 12 includes the subject matter of Example 6, wherein setting the clock rate based on the plurality of predicted values comprises determining to set the clock rate in a second setting manner based on the plurality of predicted values. Including, the plurality of reception time values include the second reception time value, the second reception time value corresponds to the second prediction value of the plurality of prediction values, and the above clock rate according to the second setting method Setting includes setting the clock rate based on the second predicted value.

Example 13 includes the subject matter of Example 12, wherein setting the clock rate based on the second predicted value comprises: setting the clock rate to a clock rate lower than the preset clock rate; Instead, recalculating the second predicted value at the lower clock rate, and maintaining the upper clock rate set at the lower clock rate or lowering the upper clock rate to the lower clock rate according to the recalculated second predicted value This includes setting the clock rate.

Example 14 includes the subject matter of Example 12, wherein setting the clock rate based on the second prediction value comprises: setting the clock rate to a clock rate lower than the preset clock rate; Instead, recalculating the second prediction value at the lower clock rate, and depending on the recalculated second prediction value, maintaining the upper clock rate set at the lower clock rate or receiving a certain amount above the higher clock rate Including setting based on the probability that a delay occurs next to the currently occurring delay.

In Example 15, a method for audio clock adjustment in a network-based public address (PA) includes: buffering digital audio data in an audio buffer for later retrieval (the digital audio data is transmitted through the network by a specific amount per determined transmission period and received by the device at successive reception timings); calculating, based on the comparison between the successive reception timings, a plurality of predicted values of an amount of the digital audio data remaining in the audio buffer immediately before a subsequent reception timing; setting a clock rate based on the plurality of predicted values; generating an audio clock signal having the set clock rate; and providing the digital audio data from the audio buffer according to the generated audio clock signal.

Example 16 includes the subject matter of Example 15, wherein the comparison includes determining whether reception of the stomach of the particular amount is normal or whether there is a delay or advance in reception of the stomach of the particular amount.

Example 17 includes the subject matter of Example 15 or Example 16, wherein setting the clock rate based on the plurality of predicted values comprises setting the clock rate based on any of a plurality of setting methods based on the plurality of predicted values. Including determining whether to set, the plurality of setting methods is a method of setting the clock rate based on a specific one of the plurality of predicted values, the probability of delay occurring in succession to the delay currently occurring in the reception of the specific amount or a method of setting the above clock rate to a predefined minimum clock rate.

Example 18 includes the subject matter of any of Examples 15-17, wherein calculating the plurality of predicted values comprises, based on the comparison, a time length from a current reception timing among the consecutive reception timings to the subsequent reception timing. predicting by a plurality of prediction methods to calculate a plurality of reception time values, and corresponding to each of the plurality of prediction values among the plurality of reception time values, a preset clock rate, and the digital audio data in the audio buffer This includes calculating based on the amount currently remaining.

Example 19 includes the subject matter of Example 18, wherein each predicted value is the product of the corresponding receive time value multiplied by the preset clock rate minus the current remaining amount.

Example 20 includes the subject matter of Examples 18 or 19, wherein the plurality of reception time values include: a first reception time value representing a predicted time to take on average to receive the reception of the particular amount; at least one second reception time value representing the expected time it will take for reception above the particular amount if there is a delay in , or, if there is an early delay in reception above the particular amount, how long it will take for reception above the particular amount and one or more of at least one third reception time value representing a time predicted to be received.

Example 21 includes the subject matter of example 20, wherein the at least one second time value is a time value representing a predicted time to take for reception of the particular amount if there is a worst-case delay for reception of the particular amount. or a time value representing an expected time taken for reception of the specific amount if there is an average delay in reception of the specific amount.

Example 22 includes the subject matter of examples 20 or 21, wherein the at least one third time value represents a predicted time that would take the reception of the particular amount of the above given that there is an average delay to the reception of the particular amount of the above. It includes at least one of a time value indicating or a time value indicating a time value that is predicted to take for reception of the particular amount if there is a worst-case premise on reception of the particular amount.

Example 23 includes the subject matter of Example 20, wherein setting the clock rate based on the plurality of predicted values comprises determining to set the clock rate in a first setting manner based on the plurality of predicted values. The plurality of reception time values include the first reception time value, the first reception time value corresponds to the first prediction value of the plurality of prediction values, and the clock rate according to the first setting method Setting includes setting the clock rate based on the first prediction value.

Example 24 includes the subject matter of Example 23, wherein setting the clock rate based on the first predicted value comprises: if the first predicted value is within a first range, setting the clock rate to the preset clock rate setting to, and if the first predicted value is within a second range covering the first range and greater than the first range, setting the clock rate to a higher clock rate than the preset clock rate; If the first prediction value is within the second range and smaller than the first range, setting the clock rate to a clock rate lower than the preset clock rate, and if the first prediction value is within the second range outside the above second range and greater than the above second range, setting the above clock rate to a clock rate higher than the above preset clock rate, and if the above first prediction value is outside the above second range and less than the above second range, the above and setting the clock rate to a clock rate lower than the preset clock rate.

Example 25 includes the subject matter of Example 24, wherein setting the clock rate to a clock rate lower than the preset clock rate comprises recalculating the first predicted value with the lower clock rate instead of the preset clock rate. , setting the clock rate to another clock rate lower than the lower clock rate when the recalculated first prediction value is outside the second range.

Example 26 includes the subject matter of Example 20, wherein setting the clock rate based on the plurality of predicted values comprises determining to set the clock rate in a second setting manner based on the plurality of predicted values. Including, the plurality of reception time values include the second reception time value, the second reception time value corresponds to the second prediction value of the plurality of prediction values, and the above clock rate according to the second setting method Setting includes setting the clock rate based on the second predicted value.

Example 27 includes the subject matter of Example 26, wherein setting the clock rate based on the second predicted value comprises: setting the clock rate to a clock rate lower than the preset clock rate; Instead, recalculating the second predicted value at the lower clock rate, and maintaining the upper clock rate set at the lower clock rate or lowering the upper clock rate to the lower clock rate according to the recalculated second predicted value This includes setting the clock rate.

Example 28 includes the subject matter of Example 26, wherein setting the clock rate based on the second predicted value comprises: setting the clock rate to a clock rate lower than the preset clock rate; Instead, recalculating the second prediction value at the lower clock rate, and depending on the recalculated second prediction value, maintaining the upper clock rate set at the lower clock rate or receiving a certain amount above the higher clock rate Including setting based on the probability that a delay occurs next to the currently occurring delay.

In Example 29, the computer-readable storage medium has computer-executable instructions stored in the computer-readable storage medium, which when executed by a computer processor cause the computer processor to cause any of Examples 15-28. to carry out the method described in

In Example 30, a computing device includes a processor and a computer-readable storage medium, wherein the computer-readable storage medium, when executed by the processor, causes the computing device to perform the method described in any of Examples 15-28. Computer-executable instructions that cause execution are stored.

In certain instances, an apparatus, device, system, machine, etc. referred to herein may be, include, or be implemented in any suitable type of computing device. A computing device may include a processor and a computer readable storage medium readable by the processor. A processor may execute one or more instructions stored in a computer readable storage medium. The processor may also read other information stored within the computer readable storage medium. Additionally, the processor may store new information in the computer readable storage medium and may update certain information stored in the computer readable storage medium. The processor includes, for example, a central processing unit (CPU), a digital signal processor (DSP), a graphics processing unit (GPU), a processor core, a microprocessor , microcontrollers, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), other hardware and logic circuits, or any suitable combination thereof. can Computer readable storage media are encoded with various information, such as a set of processor executable instructions that can be executed by a processor and/or other information. For example, a computer readable storage medium may include computer program instructions that, when executed by a processor, cause a computing device (eg, processor) to perform some of the operations disclosed herein and/or information, data, and/or data used in those operations. Variables, constants, data structures, etc. can be stored inside. Computer-readable storage media include, for example, read-only memory (ROM), random-access memory (RAM), volatile memory, non-volatile memory, removable Removable memory, non-removable memory, flash memory, solid-state memory, other types of memory devices, magnetic media such as hard disks, floppy disks and magnetic tapes, CDs - optical recording media such as ROMs, DVDs, magneto-optical media such as floptical disks, other types of storage devices and storage media, or any suitable combination thereof.

In certain instances, any action, technique, process, or any aspect or portion thereof described herein may be embodied in a computer program product. Such computer programs may be implemented in any type of (eg, compiled or interpreted) programming language that can be executed by a computer, such as assembly, machine language, procedural It can be implemented in a language, object-oriented language, etc., and can be combined with a hardware implementation. A computer program product may be distributed in the form of a computer readable storage medium or may be distributed online. For online distribution, some or all of the computer program product may be temporarily stored or temporarily created within a server (eg, a computer readable storage medium of a server).

The foregoing description has been presented to illustrate and describe several examples in detail. It will be appreciated by those skilled in the art that many modifications and variations can be made in light of the above teachings without departing from the scope of the present disclosure. In various examples, the techniques described above are performed in a different order and/or some of the components of the systems, architectures, devices, circuits and the like described above are combined or combined in different ways, replaced by other components or equivalents thereof, or Appropriate results can be achieved even when substituted.

Therefore, the scope of the present disclosure should not be limited to the form disclosed, and should be defined by the following claims and equivalents thereof.

105 Network-based public address transmitter
110: network-based public address receiver
410: audio data receiver
415 external interface
420: audio buffer
440: audio clock adjustment unit
450: audio data formatting unit
455 internal interface

Claims (21)

As a device for audio clock adjustment in a network-based public address (PA),
An audio buffer in which digital audio data is buffered for later retrieval, wherein the digital audio data is transmitted over a network in a specific amount every predetermined transmission period and received by the device at a previous reception timing and a current reception timing. Wow,
Based on the comparison between the previous reception timing and the current reception timing, the amount of digital audio data to remain in the audio buffer immediately before the next reception timing is predicted in a plurality of different ways to obtain a plurality of predicted values of the remaining amount. an audio clock adjustment unit configured to calculate, set a clock rate based on the plurality of predicted values, and generate an audio clock signal having the set clock rate;
An audio data formatting unit providing the digital audio data according to the audio clock signal generated from the audio buffer.
device. According to claim 1,
The comparison comprises determining whether the reception of the specific amount is normal or whether there is a delay or advance in the reception of the specific amount.
device. According to claim 1,
Setting the clock rate based on the plurality of predicted values includes determining which of a plurality of setting methods to set the clock rate based on the plurality of predicted values,
The plurality of setting methods is a method of setting the clock rate based on a specific one of the plurality of predicted values, a method of setting the clock rate based on a probability that a delay will occur subsequent to a delay currently occurring in the reception of the specific amount , or a manner of setting the clock rate to a predefined lowest clock rate,
device. According to claim 1,
Calculating the plurality of predicted values,
Based on the comparison, calculating a plurality of reception time values by estimating a length of time from the current reception timing to the next reception timing using a plurality of predictive methods;
Calculating each of the plurality of predicted values based on a corresponding one of the plurality of reception time values, a preset clock rate, and an amount of the digital audio data currently remaining in the audio buffer,
device. According to claim 4,
The plurality of reception time values include: a first reception time value representing a time expected to take on average for the reception of the specific amount; at least one second time-of-reception value representing the time expected to occur, or at least one third time-of-reception value representing the expected time it would take for the reception of the particular amount if there is an early delay in the reception of the particular amount. Including one or more of
device. According to claim 5,
Setting the clock rate based on the plurality of prediction values includes determining to set the clock rate in a first setting method based on the plurality of prediction values,
The plurality of reception time values include the first reception time value, the first reception time value corresponds to a first prediction value of the plurality of prediction values, and setting the clock rate by the first setting method comprising setting the clock rate based on the first predicted value;
device. According to claim 6,
Setting the clock rate based on the first prediction value,
If the first predicted value is within a first range, setting the clock rate to the preset clock rate;
If the first predicted value is within a second range covering the first range and greater than the first range, setting the clock rate to a higher clock rate than the preset clock rate;
If the first prediction value is within the second range and less than the first range, setting the clock rate to a clock rate lower than the preset clock rate;
If the first predicted value is outside the second range and is greater than the second range, setting the clock rate to a higher clock rate than the preset clock rate;
If the first prediction value is outside the second range and smaller than the second range, setting the clock rate to a clock rate lower than the preset clock rate,
device. According to claim 5,
Setting the clock rate based on the plurality of prediction values includes determining to set the clock rate in a second setting method based on the plurality of prediction values,
The plurality of reception time values include the second reception time value, the second reception time value corresponds to a second prediction value of the plurality of prediction values, and the second setting method to set the clock rate Which includes setting the clock rate based on the second predicted value,
device. According to claim 8,
Setting the clock rate based on the second prediction value,
setting the clock rate to a clock rate lower than the preset clock rate;
recalculating the second predicted value with the lower clock rate instead of the preset clock rate;
According to the recalculated second predicted value, maintaining the clock rate set to the low clock rate or setting the clock rate to a clock rate lower than the low clock rate,
device. According to claim 8,
Setting the clock rate based on the second prediction value,
setting the clock rate to a clock rate lower than the preset clock rate;
recalculating the second predicted value with the lower clock rate instead of the preset clock rate;
In accordance with the recalculated second predicted value, maintaining the clock rate set to the low clock rate or setting the clock rate based on a probability that a delay will occur subsequent to a delay currently occurring in the reception of the specific amount doing,
device. A method performed by a network-based PA receiver for audio clock adjustment in a network-based public address (PA), comprising:
buffering, by the network-based PA receiver, digital audio data in an audio buffer for later retrieval, wherein the digital audio data is transmitted over the network in a specific amount every predetermined transmission period and transferred by the network-based PA receiver Received at the reception timing and the current reception timing - Wow,
By means of the network-based PA receiver, based on a comparison between the previous reception timing and the current reception timing, an amount of the digital audio data to remain in the audio buffer immediately before a subsequent reception timing is predicted in a plurality of different ways, and the remaining amount is predicted by the network-based PA receiver. Calculating a plurality of predicted values of the amount to be done;
setting, by the network-based PA receiver, a clock rate based on the plurality of prediction values;
generating, by the network-based PA receiver, an audio clock signal having the set clock rate;
providing, by the network-based PA receiver, the digital audio data according to the generated audio clock signal from the audio buffer.
method. According to claim 11,
wherein the comparison comprises determining, by the network-based PA receiver, whether the reception of the particular amount is normal or whether there is a delay or advance in the reception of the particular amount.
method. According to claim 11,
The setting of the clock rate by the network-based PA receiver based on the plurality of predicted values may cause the clock rate to be set by any one of a plurality of setting methods based on the plurality of predicted values by the network-based PA receiver. Including determining whether to set a rate;
The plurality of setting methods are a method of setting the clock rate based on a specific one of the plurality of predicted values, a method of setting the clock rate based on a probability that a delay will occur subsequent to a delay currently occurring in the reception of the specific amount , or a manner of setting the clock rate to a predefined lowest clock rate,
method. According to claim 11,
Calculating the plurality of predicted values by the network-based PA receiver,
calculating, by the network-based PA receiver, a plurality of reception time values by estimating a length of time from the current reception timing to the subsequent reception timing based on the comparison using a plurality of predictive methods;
Calculating, by the network-based PA receiver, each of the plurality of prediction values based on a corresponding one of the plurality of reception time values, a preset clock rate, and an amount of the digital audio data currently remaining in the audio buffer including,
method. According to claim 14,
The plurality of reception time values include: a first reception time value representing a time expected to take on average for the reception of the specific amount; at least one second time-of-reception value representing the time expected to occur, or at least one third time-of-reception value representing the expected time it would take for the reception of the particular amount if there is an early delay in the reception of the particular amount. Including one or more of
method. According to claim 15,
Setting the clock rate by the network-based PA receiver based on the plurality of predicted values may include setting the clock rate in a first setting method based on the plurality of predicted values by the network-based PA receiver. Including determining to set,
The plurality of reception time values include the first reception time value, the first reception time value corresponds to a first prediction value of the plurality of prediction values, and, by the network-based PA receiver, the first setting Setting the clock rate in a manner comprising setting, by the network-based PA receiver, the clock rate based on the first prediction value;
method. According to claim 16,
Setting, by the network-based PA receiver, the clock rate based on the first predicted value,
If the first predicted value is within a first range, setting, by the network-based PA receiver, the clock rate to the preset clock rate;
If the first predicted value is within a second range covering the first range and greater than the first range, setting the clock rate to a higher clock rate than the preset clock rate by the network-based PA receiver doing and
If the first predicted value is within the second range and less than the first range, setting, by the network-based PA receiver, the clock rate to a clock rate lower than the preset clock rate;
If the first predicted value is outside the second range and is greater than the second range, setting, by the network-based PA receiver, the clock rate to a higher clock rate than the preset clock rate;
If the first predicted value is outside the second range and smaller than the second range, setting, by the network-based PA receiver, the clock rate to a clock rate lower than the preset clock rate,
method. According to claim 15,
Setting the clock rate based on the plurality of prediction values by the network-based PA receiver may include setting the clock rate by a second setting method based on the plurality of prediction values by the network-based PA receiver. Including determining to set,
The plurality of reception time values include the second reception time value, the second reception time value corresponds to a second prediction value of the plurality of prediction values, and the network-based PA receiver determines the second reception time value. Setting the clock rate in a manner comprising setting, by the network-based PA receiver, the clock rate based on the second predicted value,
method. According to claim 18,
Setting, by the network-based PA receiver, the clock rate based on the second predicted value,
setting, by the network-based PA receiver, the clock rate to a clock rate lower than the preset clock rate;
recalculating, by the network-based PA receiver, the second predicted value with the lower clock rate instead of the preset clock rate;
By the network-based PA receiver, according to the recalculated second prediction value, maintaining the clock rate set to the low clock rate or setting the clock rate to a clock rate lower than the low clock rate,
method. According to claim 18,
Setting, by the network-based PA receiver, the clock rate based on the second predicted value,
setting, by the network-based PA receiver, the clock rate to a clock rate lower than the preset clock rate;
recalculating, by the network-based PA receiver, the second predicted value with the lower clock rate instead of the preset clock rate;
By the network-based PA receiver, according to the recalculated second prediction value, maintaining the clock rate set at the lower clock rate or increasing the clock rate to cause a delay subsequent to a delay currently occurring in the reception of the specified amount Including setting based on probability,
method. delete

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