Audio output method, projector and program

Abstract

To provide an audio output method that more effectively suppresses noise.SOLUTION: A second processor 270 of a second control unit 250 executes the following: dividing received audio data of a predetermined size into multiple partial audio data; detecting partial audio data whose audio amplitude at the end of the partial audio data exceeds a predetermined range among the multiple partial audio data; and executing end processing to bring the audio amplitude at the end of the detected partial audio data within the predetermined range. Detecting the partial audio data detects partial audio data with the audio amplitude exceeding a predetermined range for either partial audio data located at the end of continuously received audio data, or before and after partial audio data surrounding a lost portion of audio data as targets, when the portion of the audio data is lost.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an audio output method, a projector, and a program. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there are known techniques for reducing noise that occurs when audio data received via wireless communication is reproduced.

[0003] For example, Patent Document 1 discloses a program for removing noise by correcting an audio waveform within a predetermined time range based on the joint portion of a plurality of separated audio data. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-22199 Summary of the Invention [Problem to be solved by the invention]

[0005] However, noise generation factors are not limited to the joints of audio data, and therefore, a technique for suppressing noise more effectively is desired. [Means for solving the problem]

[0006] The present disclosure is an audio output method that causes a processor included in an audio output device to divide audio data received from outside into predetermined sizes to generate a plurality of partial audio data, detect partial audio data from the plurality of partial audio data whose audio amplitude at an end of the partial audio data is greater than a predetermined range, and perform edge processing to bring the audio amplitude at the end of the detected partial audio data within the predetermined range, wherein detecting the partial audio data includes detecting partial audio data whose audio amplitude is greater than the predetermined range, targeting the partial audio data located at the end of the continuously received audio data, or, when a portion of the audio data is lost, the partial audio data before and after the lost portion of audio data.

[0007] The present disclosure relates to a projector that includes a receiving unit that receives audio data and a processor that processes the received audio data, and that causes the processor to perform the following: divide audio data received from outside into predetermined size segments to generate a plurality of partial audio data; detect, from among the plurality of partial audio data, partial audio data whose audio amplitude at the end of the partial audio data is greater than a predetermined range; and perform edge processing to bring the audio amplitude at the end of the detected partial audio data within the predetermined range; and the detecting of the partial audio data includes detecting partial audio data whose audio amplitude is greater than the predetermined range, targeting the partial audio data located at the end of the audio data received continuously, or, when a portion of the audio data is lost, the partial audio data before and after the lost portion of audio data.

[0008] The present disclosure is a program that causes a processor mounted on a computer to divide audio data received from outside into predetermined size chunks to generate a plurality of partial audio data; detect, from among the plurality of partial audio data, partial audio data whose audio amplitude at an end of the partial audio data is greater than a predetermined range; and perform edge processing to bring the audio amplitude at the end of the detected partial audio data within the predetermined range, wherein detecting the partial audio data includes detecting partial audio data whose audio amplitude is greater than the predetermined range, targeting the partial audio data located at the end of the continuously received audio data, or, when a portion of the audio data is lost, the partial audio data before and after the lost portion of audio data. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the system configuration of a projection system. [Figure 2] FIG. 2 is a block diagram showing the configuration of a terminal device and a projector. [Figure 3] FIG. 10 is a diagram showing an audio waveform when an interruption occurs in audio data. [Figure 4] FIG. 10 is a diagram showing an audio waveform after edge processing. [Figure 5] 10 is a flowchart showing the operation of a buffer processing unit. [Figure 6] 6 is a flowchart showing the operation of the edge processing section of the first embodiment. [Figure 7] FIG. 10 is a diagram showing an audio waveform of audio data in which a portion has been lost. [Figure 8] FIG. 10 is a diagram showing an audio waveform after the first audio block and the second audio block are connected. [Figure 9] FIG. 10 is a diagram showing an audio waveform of audio data before loss. [Figure 10] FIG. 10 is a diagram showing an audio waveform in the case where the phase is not continuous due to the concatenation of the first audio block and the second audio block. [Figure 11] FIG. 10 is a diagram showing the first connection point before change and the first connection point after change. [Figure 12]10 is a flowchart showing the operation of the edge processing section according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [1. System Configuration of First Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing the system configuration of a projection system 1. As shown in FIG. The display system 1 includes a terminal device 100 and a projector 200. The terminal device 100 is a device that supplies packet data including image data and audio data to the projector 200. The terminal device 100 may be, for example, a mobile terminal device such as a smartphone, a tablet, a notebook PC, a portable game console, or a wearable device, or a stationary device such as a desktop PC.

[0011] The projector 200 corresponds to an audio output device, and projects an image based on image data supplied from the terminal device 100 onto the projection surface 10, and outputs audio based on audio data supplied from the terminal device 100 from a speaker 225. Note that the audio output device is not limited to a projector, and may be headphones, a television, an AI speaker, or the like.

[0012] The terminal device 100 and the projector 200 are connected by wireless communication. The communication between the terminal device 100 and the projector 200 may be a wireless connection via a network, or may be two-way communication between the terminal device 100 and the projector 200 by P2P (peer-to-peer) using WebRTC (Web Real-Time Communication), for example.

[0013] 2. Configuration of the Terminal Device of the First Embodiment FIG. 2 is a block diagram showing the configuration of the terminal device 100 and the projector 200. As shown in FIG. First, the configuration of the terminal device 100 will be described. The terminal device 100 includes a first wireless communication interface 110, a touch panel 130, and a first control unit 150. Hereinafter, the interface will be abbreviated as I / F.

[0014] The first wireless communication I / F 110 includes a communication module including an antenna and an interface circuit. The communication method of the first wireless communication I / F 110 may be, for example, a communication standard using a mobile communication network such as 4G (Generation), 5G, or LTE (Long Term Evolution), or a wireless communication standard such as a wireless LAN (Local Area Network) such as Wi-Fi. Wi-Fi is a registered trademark.

[0015] The touch panel 130 includes a display panel and a touch sensor. The display panel and the touch sensor are not shown in the drawings. For example, a liquid crystal panel or an organic EL (Electro-Luminescence) panel is used as the display panel. The touch sensor detects a touch operation on the touch panel 130. The touch sensor detects, as a touch operation, a position on the touch panel 130 that is touched by a pointer such as an electronic pen or a user's finger. The touch sensor outputs an operation signal to the first control unit 150, which includes coordinate information indicating the position on the touch panel 130 where the touch operation was detected.

[0016] The first control unit 150 is a computer device that includes a first storage unit 160 and a first processor 170 .

[0017] The first storage unit 160 includes a RAM (Random Access Memory) and a ROM (Read Only Memory). The RAM is used for temporary storage of various data and the like. The ROM stores control programs such as an OS (Operating System) 161 that controls the operation of the terminal device 100 and an application program 163, as well as various setting information. The application program will be abbreviated as APP below.

[0018] The first processor 170 is an arithmetic processing device configured by a CPU (Central Processing Unit) and an MPU (Micro Processor Unit). The first processor 170 executes the OS 161 and the APP 163 to control each part of the terminal device 100. The first processor 170 may be configured by a single processor or may be configured by multiple processors.

[0019] The first control unit 150 that executes the APP 163 wirelessly connects to the projector 200 and transmits packet data to the projector 200, including image data of moving images and still images, and audio data.

[0020] For example, UDP / IP (User Datagram Protocol / Internet Protocol) is used for communication between the terminal device 100 and the projector 200. The UDP / IP protocol does not acknowledge the arrival of packet data and ignores any packets that do not arrive, so the packets that do not arrive are not resent, which can result in momentary or intermittent interruptions in the video or audio being played.

[0021] 3. Configuration of the Projector of the First Embodiment Next, the configuration of the projector 200 will be described. The projector 200 includes a second wireless communication I / F 210 , an audio driver 220 , a speaker 225 , an image processing unit 230 , an image projection unit 240 , and a second control unit 250 .

[0022] The second wireless communication I / F 210 includes a communication module including an antenna and an interface circuit. The communication method of the second wireless communication I / F 210 employs a communication standard using a mobile communication network such as 4G, 5G, or LTE, or a wireless communication standard such as a wireless LAN such as Wi-Fi.

[0023] The second wireless communication I / F 210 receives packet data transmitted from the terminal device 100. The second wireless communication I / F 210 outputs the received packet data to the second control unit 250.

[0024] The audio driver 220 converts the digital audio data input from the second control unit 250 into an analog audio signal, and outputs the converted audio signal from the speaker 225 .

[0025] The image processing unit 230 is connected to a frame memory 235. The frame memory 235 includes a plurality of banks. Each bank has a storage capacity capable of writing one frame of image. The frame memory 235 is configured, for example, with an SDRAM (Synchronous Dynamic RAM). The image processing unit 230 develops an image based on image data received by the second wireless communication I / F 210 in the frame memory 235.

[0026] The image processing unit 230 performs image processing on the image expanded in the frame memory 235. The image processing performed by the image processing unit 230 includes, for example, resolution conversion processing or resizing processing, distortion correction, shape correction processing, digital zoom processing, and adjustment of image color and brightness. The image processing unit 230 executes processing specified by the second control unit 250, and, if necessary, performs processing using parameters input from the second control unit 250. Of course, the image processing unit 230 can also execute a combination of multiple image processing operations described above.

[0027] The image processing unit 230 and the frame memory 235 are configured, for example, by an integrated circuit. The integrated circuit includes an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), an FPGA (Field-Programmable Gate Array), an SoC (System-on-a-chip), etc. An analog circuit may be included as part of the integrated circuit configuration, or the second control unit 250 may be configured in combination with an integrated circuit.

[0028] The image projection unit 240 includes a light source 241 , a light modulation device 243 , and an optical unit 245 .

[0029] The light source 241 includes a discharge light source lamp such as an ultra-high pressure mercury lamp or a metal halide lamp, or a solid-state light source such as a light-emitting diode or a semiconductor laser.

[0030] The light modulation device 243 is a light modulation element that modulates the light emitted from the light source 241 and includes a transmissive liquid crystal panel in which liquid crystal is sealed between a pair of transparent substrates. The liquid crystal panel is not shown. The liquid crystal panel includes a panel region consisting of a plurality of pixels arranged in a matrix. The light modulation device 243 applies a drive voltage corresponding to an image signal input from the image processing unit 230 to each pixel in the panel region, and changes the light transmittance of each pixel to the transmittance corresponding to the image signal. The light emitted from the light source 241 is modulated by passing through the liquid crystal panel, and image light corresponding to the image signal is generated.

[0031] The light modulation element provided in the light modulation device 243 is not limited to a transmissive liquid crystal panel, but may be, for example, a reflective liquid crystal panel or a DMD (Digital Micromirror Device).

[0032] The optical unit 245 includes a projection lens (not shown) and projects the image light modulated by the light modulation device 243 onto the projection surface 10 in an enlarged form. As a result, a projection image corresponding to the image light is displayed on the projection surface 10.

[0033] The second control unit 250 is a computer device that includes a second storage unit 260 and a second processor 270.

[0034] The second storage unit 260 includes a RAM (Random Access Memory) and a ROM (Read Only Memory). The RAM is used for temporary storage of various data and the like. The RAM has an audio buffer 261 formed therein for temporarily storing audio data. The ROM stores control programs such as firmware 263 and APP 265 that control the operation of the projector 200, as well as various setting information and the like.

[0035] The second processor 270 is an arithmetic processing device configured with a CPU or MPU. The second processor 270 executes a control program to control each unit of the projector 200. The second processor 270 may be configured with a single processor or multiple processors. The second processor 270 may also be configured with a SoC (System-on-a-Chip) integrated with part or all of the second storage unit 260 or other circuits. The second processor 270 may also be configured with a combination of a CPU that executes a program and a DSP (Digital Signal Processing) that executes predetermined arithmetic processing. Furthermore, all of the functions of the second processor 270 may be implemented in hardware, or may be configured using a programmable device.

[0036] 4. Operation of the Projector of the First Embodiment The second control unit 250 includes, as functional blocks, a buffer processing unit 271 and an edge processing unit 273. These functional blocks are functions that are realized when the second processor 270 executes the APP 265.

[0037] The buffer processing unit 271 receives packet data that the second wireless communication I / F 210 receives from the terminal device 100. The buffer processing unit 271 extracts image data and audio data included in the input packet data. The buffer processing unit 271 outputs the extracted image data to the image processing unit 230, and causes the image processing unit 230 to process the image data.

[0038] The buffer processing unit 271 also extracts audio data contained in the packet data. The buffer processing unit 271 divides the extracted audio data into pieces of a predetermined size. The divided pieces of audio data of a predetermined size are called audio blocks. An audio block corresponds to partial audio data. As an example, if the size of the audio data contained in the packet data is 1024 bytes, the buffer processing unit 271 divides the packet data into 256-byte pieces to generate 256-byte audio blocks.

[0039] After generating a plurality of audio blocks, the buffer processing unit 271 stores the generated audio blocks in the audio buffer 261 of the second storage unit 260.

[0040] The end processing unit 273 reads the audio block from the audio buffer 261 and outputs the read audio block to the audio driver 220 .

[0041] Furthermore, when the number of audio blocks stored in the audio buffer 261 becomes one due to factors such as an interruption in audio data, the edge processing unit 273 performs edge processing on the read audio block. One audio block stored in the audio buffer 261 corresponds to partial audio data located at the end of continuously received audio data. Edge processing is a process of adjusting the audio amplitude at the edge of an audio block to fall within a predetermined range. For example, the edge processing unit 273 may delete audio data at the edge of an audio block, or may adjust the audio amplitude at the edge of an audio block to fall within the predetermined range. The edge processing unit 273 may also gradually reduce the audio amplitude at the edge of an audio block to correct the audio amplitude to fall within the predetermined range. The predetermined range is, for example, a range defined by an upper and lower limit of the amplitude and may include zero. The predetermined range may also be a range defined by the magnitude of the amplitude, in which case the center of the predetermined range is set to zero. The predetermined range may be any range of audio amplitude that cannot be recognized by humans. A preferred example is setting the predetermined range to zero. In this example, the predetermined range does not have a size, and being within the predetermined range means that the amplitude is 0. In the following, an example in which the predetermined range is 0 will be described.

[0042] 3 and 4 are diagrams showing audio waveforms when an interruption occurs in the audio data. In particular, Fig. 3 is a diagram showing the audio waveform before edge processing, and Fig. 4 is a diagram showing the audio amplitude after edge processing. Note that although Figs. 3 and 4 show analog audio waveforms, the audio data transmitted from the terminal device 100 to the projector 200 is digital, and the audio data processed by the second control unit 250 is also digital audio data.

[0043] The edge processing unit 273 reads an audio block from the audio buffer 261. The edge processing unit 273 outputs the read audio block to the audio driver 220. At this time, if the number of audio blocks stored in the audio buffer 261 is one, the edge processing unit 273 determines whether the audio amplitude at the end of the read audio block is within a predetermined range.

[0044] The end processing unit 273 detects the point at which the audio amplitude finally becomes 0 at the rear end of the read audio block. The end processing unit 273 detects point A shown in FIG. 3 as the point at which the audio amplitude finally becomes 0. The end processing unit 273 deletes the audio data of section B, which is the section after the detected point A. Alternatively, the end processing unit 273 processes the audio amplitude of section B to 0.

[0045] 5 is a flowchart showing the operation of the buffer processing unit 271. The operation of the buffer processing unit 271 will be described with reference to the flowchart shown in FIG. First, the buffer processing unit 271 determines whether or not packet data has been input from the second wireless communication I / F 210 (step S1). If packet data has not been input (step S1 / NO), the buffer processing unit 271 waits until packet data is input.

[0046] When packet data is input from the second wireless communication I / F 210 (step S1 / YES), the buffer processing unit 271 extracts the audio data included in the packet data (step S2) and divides the extracted audio data into audio blocks of a predetermined size (step S3). The buffer processing unit 271 stores the generated audio blocks in the audio buffer 261 (step S4).

[0047] After storing the generated audio block in the audio buffer 261, the buffer processing unit 271 returns to step S1, determines whether the next packet data has been input, and waits until the next packet data is input.

[0048] 6 is a flowchart showing the operation of the edge processing unit 273. The operation of the edge processing unit 273 will be described with reference to the flowchart shown in FIG. First, the edge processing unit 273 determines whether or not an audio block is stored in the audio buffer 261 (step S11). If an audio block is not stored in the audio buffer 261 (step S11 / NO), the edge processing unit 273 waits until an audio block is stored in the audio buffer 261.

[0049] If an audio block is stored in the audio buffer 261 (step S11 / YES), the end processing unit 273 determines whether the number of audio blocks stored in the audio buffer 261 is one (step S12).

[0050] If the number of audio blocks stored in the audio buffer 261 is not one (step S12 / NO), the edge processing unit 273 reads an audio block from the audio buffer 261 (step S13). Next, the edge processing unit 273 outputs the read audio block to the audio driver 220 (step S14).

[0051] Also, if there is one audio block stored in the audio buffer 261 (step S12 / YES), the edge processing unit 273 reads out the audio block from the audio buffer 261 (step S15). The edge processing unit 273 performs edge processing on the end of the read audio block (step S16). The edge processing unit 273 detects point A at the end of the audio block where the audio amplitude finally becomes 0. The edge processing unit 273 deletes the audio data of section B, which is the section after the detected point A. Alternatively, the edge processing unit 273 processes the audio amplitude of section B to 0.

[0052] The edge processing unit 273 outputs the edge-processed audio block to the audio driver 220 (step S14).

[0053] After outputting the audio block to the audio driver 220, the end processing unit 273 determines whether or not an audio block is stored in the audio buffer 261 (step S17). If an audio block is stored in the audio buffer 261 (step S17 / YES), the end processing unit 273 returns to step S12 and determines whether or not the number of audio blocks stored in the audio buffer 261 is one.

[0054] Furthermore, if no audio blocks are stored in the audio buffer 261 (step S17 / NO), the end processing unit 273 determines whether or not the reception of audio data has finished (step S18). If the reception of audio data has not finished (step S18 / NO), the end processing unit 273 returns to the determination in step S17 and determines whether or not an audio block is stored in the audio buffer 261. Furthermore, if the reception of audio data has finished (step S18 / YES), the end processing unit 273 ends this processing flow.

[0055] 5. Operation of the Projector of the Second Embodiment The second embodiment will be described with reference to the accompanying drawings. The configurations of the terminal device 100 and the projector 200 in the second embodiment are the same as those in the first embodiment shown in FIG. 2, and therefore a description of the configurations of the terminal device 100 and the projector 200 will be omitted.

[0056] In the second embodiment, when a portion of audio data transmitted from the terminal device 100 is lost, the projector 200 concatenates the audio blocks before and after the lost audio data, and outputs the concatenated audio data from the speaker 225.

[0057] An identification number that identifies each packet is included in the header of the packet data received by the second wireless communication I / F 210. The buffer processing unit 271 detects a loss of audio data by detecting discontinuities in the identification numbers included in the packet headers.

[0058] Furthermore, when the buffer processing unit 271 divides the audio data into predetermined size segments to generate audio blocks, it assigns a block number to each generated audio block to identify the audio block. When the buffer processing unit 271 detects the loss of packet data, it notifies the end processing unit 273 of the loss of the packet data, the block number of the last audio block before the packet loss, and the block number of the first audio block after the packet loss. Hereinafter, the last audio block before the packet loss will be referred to as the first audio block, and the first audio block after the packet loss will be referred to as the second audio block.

[0059] FIG. 7 is a diagram showing an audio waveform of audio data in which a part has been lost. The portion indicated by the dashed line in FIG. 7 shows the lost audio data. When the buffer processing unit 271 notifies the edge processing unit 273 of the loss of packet data, the edge processing unit 273 identifies the first audio block and the second audio block based on the block number notified by the buffer processing unit 271.

[0060] Next, the edge processing unit 273 performs edge processing on the end of the first audio block and the beginning of the second audio block. First, the end processing unit 273 identifies the point at the end on the termination side of the first audio block where the audio amplitude finally becomes 0. This point is called the first connection point. Also, the end processing unit 273 identifies the point at the end on the start side of the second audio block where the audio amplitude first becomes 0. This point is called the second connection point. The first connection point and the second connection point correspond to connection points.

[0061] Next, the end processing unit 273 determines whether the audio amplitude of the audio data for 1 / 2 cycle including the first connection point and before the first connection point and the audio amplitude of the audio data for 1 / 2 cycle including the second connection point and after the second connection point are positive or negative.

[0062] In the example shown in FIG. 7, the half-cycle section including the first connection point and preceding the first connection point corresponds to section C. Also, the half-cycle section including the second connection point and following the second connection point corresponds to section D. Hereinafter, the half-cycle section including the first connection point and preceding the first connection point will be referred to as first section C, and the half-cycle section including the second connection point and following the second connection point will be referred to as second section D. Also, FIG. 7 shows a case where the audio amplitude in first section C is positive and the audio amplitude in second section D is negative.

[0063] For example, the end processing unit 273 determines that the positive and negative signs are different when the audio amplitude in the first section C is positive, i.e., a peak, and the audio amplitude in the second section D is negative, i.e., a valley. The end processing unit 273 also determines that the positive and negative signs are different when the audio amplitude in the first section C is negative, i.e., a valley, and the audio amplitude in the second section D is positive, i.e., a peak.

[0064] Furthermore, the end processing unit 273 determines that the positive and negative signs are the same when the audio amplitude in the first section C is positive, that is, a peak, and the audio amplitude in the second section D is also positive, that is, a peak. Furthermore, the end processing unit 273 also determines that the positive and negative signs are the same when the audio amplitude in the first section C is negative, that is, a valley, and the audio amplitude in the second section D is also negative, that is, a valley.

[0065] Figure 8 is a diagram showing an audio waveform obtained by connecting the first audio block and the second audio block shown in Figure 7. More specifically, it shows an audio waveform obtained by connecting the first audio block and the second audio block from which some audio data has been removed, by removing the audio data after the first connection point and the audio data before the second connection point. As shown in Figure 7, when the audio amplitude of the first section C and the audio amplitude of the second section D are positive or negative and are concatenated with the first audio block and the second audio block from which some audio data has been deleted, the audio waveform after concatenation will have a continuous phase, as shown in Figure 8.

[0066] Fig. 9 is a diagram showing an audio waveform of audio data in which a part has been lost. Fig. 10 is a diagram showing an audio waveform in which the first audio block and the second audio block shown in Fig. 9 are concatenated. Fig. 9 shows an audio waveform when the audio amplitude of the first section C is the same as the positive or negative sign of the audio amplitude of the second section D. As shown in Fig. 9, when the audio amplitude of the first section C is the same as the positive or negative sign of the audio amplitude of the second section D, if the first audio block and the second audio block from which the audio data at the ends has been deleted are concatenated, the audio waveform after concatenation will have a discontinuous phase as shown in Fig. 10.

[0067] FIG. 11 is a diagram showing an example in which the position of the first connection point is changed to a position that is 1 / 2 period earlier. The end processing unit 273 changes the position of either the first connection point or the second connection point when the audio amplitude of the first section C and the audio amplitude of the second section D are the same in sign. For example, the end processing unit 273 sets the point 1 / 2 period before the first connection point as the new first connection point. In other words, the end processing unit 273 sets the point immediately before the first connection point where the audio amplitude is 0 as the new first connection point. Furthermore, the end processing unit 273 may change the second connection point when the audio amplitude in the first section C and the audio amplitude in the second section D are of the same sign. The end processing unit 273 sets the point 1 / 2 period after the second connection point as the new second connection point. In other words, the point one period after the second connection point where the audio amplitude is 0 is set as the new second connection point.

[0068] When the position of the first connection point or the second connection point is changed, the edge processing unit 273 processes the audio amplitude of the first audio block so that the audio amplitude after the first connection point of the first audio block becomes 0. Alternatively, the edge processing unit 273 deletes the audio data after the first connection point of the first audio block. Furthermore, the edge processing unit 273 processes the audio amplitude of the second audio block so that the audio amplitude before the second connection point of the second audio block becomes 0. Alternatively, the edge processing unit 273 deletes the audio data after the second connection point of the second audio block.

[0069] Next, the edge processing unit 273 outputs the edge-processed first audio block and second audio block to the audio driver 220. The edge processing unit 273 outputs the first audio block and the second audio block to the audio driver 220 so that they are continuous. The audio driver 220 processes the input first audio block and second audio block in order, so that the first audio block and the second audio block are concatenated and continuous audio is output from the speaker 225.

[0070] FIG. 12 is a flowchart showing the operation of the edge processing section 273 in the second embodiment. The operation of the edge processing unit 273 will be described with reference to the flowchart shown in FIG. First, the edge processing unit 273 determines whether or not an audio block is stored in the audio buffer 261 (step S21). If an audio block is not stored in the audio buffer 261 (step S21 / NO), the edge processing unit 273 waits until an audio block is stored in the audio buffer 261.

[0071] If an audio block is stored in the audio buffer 261 (step S21 / YES), the end processing unit 273 reads the stored audio block from the audio buffer 261 (step S22).

[0072] Next, the edge processing unit 273 determines whether or not loss of packet data has been detected (step S23). When the edge processing unit 273 receives a notification from the buffer processing unit 271 that loss of packet data has been detected, the edge processing unit 273 determines that loss of packet data has been detected.

[0073] If no loss of packet data is detected (step S23 / NO), the end processing unit 273 outputs the read audio block to the audio driver 220 (step S24).

[0074] Furthermore, when packet data loss is detected (step S23 / YES), the edge processing unit 273 determines whether the audio block read from the audio buffer 261 corresponds to the first audio block or the second audio block (step S25). The edge processing unit 273 determines whether the block number of the read audio block matches the block number notified by the buffer processing unit 271.

[0075] If the read audio blocks do not correspond to the first audio block or the second audio block (step S25 / NO), the end processing unit 273 outputs the read audio blocks to the audio driver 220 in the order in which they were read (step S24). After that, the end processing unit 273 proceeds to the determination of step S34. Details of the determination of step S35 will be described later.

[0076] If the read audio block corresponds to the first audio block and the second audio block (step S25 / YES), the edge processing unit 273 sets a first connection point and a second connection point (step S26). The edge processing unit 273 sets the point where the audio amplitude finally becomes 0 in the first audio block as the first connection point. Also, the edge processing unit 273 sets the point where the audio amplitude first becomes 0 in the second audio block as the second connection point.

[0077] Next, the end processing unit 273 determines whether the audio amplitude of the first section C and the audio amplitude of the second section D are positive or negative (step S27). The first section C includes the first connection point and is a section of 1 / 2 cycle before the first connection point. The second section D includes the second connection point and is a section of 1 / 2 cycle after the second connection point.

[0078] If the audio amplitude of the first section C and the audio amplitude of the second section D are of the same sign (step S27 / YES), the end processing unit 273 changes the position of the first connection point or the second connection point (step S28). For example, the end processing unit 273 sets a point that is 1 / 2 cycle before the first connection point before the change and where the audio amplitude is 0 as the changed first connection point. Alternatively, the end processing unit 273 may set a point that is 1 / 2 cycle after the second connection point before the change and where the audio amplitude is 0 as the changed second connection point.

[0079] Next, the edge processing unit 273 performs edge processing by processing the audio amplitude of the first audio block after the first connection point to 0 (step S29). The edge processing unit 273 performs edge processing and outputs the first audio block whose audio amplitude has been processed to 0 to the audio driver 220 (step S30).

[0080] Next, the edge processing unit 273 performs edge processing by changing the audio amplitude of the second audio block before the second connection point to 0 (step S31). The edge processing unit 273 performs edge processing and outputs the second audio block, whose audio amplitude has been changed to 0, to the audio driver 220 (step S32). After this, the edge processing unit 273 proceeds to the determination of step S34. Details of the determination of step S34 will be described later.

[0081] Furthermore, if the audio amplitude of the first section C and the audio amplitude of the second section D are different in sign, the end processing unit 273 outputs the first audio block to the audio driver 220 (step S33). After that, the end processing unit 273 outputs the second audio block to the audio driver 220 (step S34).

[0082] Next, the edge processing unit 273 determines whether or not audio data is stored in the audio buffer 261 (step S35). If audio data is stored in the audio buffer 261 (step S35 / YES), the edge processing unit 273 returns to step S22 and reads out an audio block from the audio buffer 261 (step S22).

[0083] Furthermore, if no audio data is stored in the audio buffer 261 (step S35 / NO), the end processing unit 273 determines whether or not the reception of the audio data has finished (step S36). If the reception of the audio data has not finished (step S36 / NO), the end processing unit 273 returns to the determination in step S35 and determines whether or not an audio block is stored in the audio buffer 261. Furthermore, if the reception of the audio data has finished (step S36 / YES), the end processing unit 273 ends this processing flow.

[0084] 6. Other Embodiments The above-described embodiment is a preferred embodiment of the present invention, but the present invention is not limited to the above-described embodiment and various modifications are possible within the scope of the gist of the present invention.

[0085] For example, the processing units in the flowcharts shown in Figures 5, 6, and 12 are divided according to the main processing content in order to make the processing of projector 200 easier to understand. The present invention is not limited to the manner in which the processing units shown in the flowcharts shown in Figures 5, 6, and 12 are divided or the names of the processing units. Furthermore, the processing of second control unit 250 can be divided into more processing units according to the processing content, or one processing unit can be divided so that it includes more processes. Furthermore, the processing order of the above flowcharts is not limited to the example shown in the figures.

[0086] Furthermore, the functional units of the terminal device 100 and the projector 200 shown in FIG. 2 indicate functional configurations, and the specific implementation form is not particularly limited. In other words, it is not necessary to implement hardware corresponding to each functional unit individually, and it is of course possible to configure the system so that a single processor executes a program to realize the functions of multiple functional units. Furthermore, some of the functions realized by software in the above embodiments may be realized by hardware, and some of the functions realized by hardware may be realized by software. In addition, the specific detailed configurations of the other units of the terminal device 100 and the projector 200 may also be changed as desired without departing from the spirit of the present invention.

[0087] Furthermore, when the audio output method of the audio output device is implemented by the second processor 270 included in the projector 200, the program executed by the processor can be configured in the form of a recording medium. Alternatively, the program can be configured in the form of a transmission medium for transmitting the program executed by the processor. The recording medium can be a magnetic or optical recording medium or a semiconductor memory device. Specific examples include portable or fixed recording media such as flexible disks, HDDs, CD-ROMs, DVDs (Digital Versatile Discs), Blu-ray Discs, magneto-optical discs, flash memories, and card-type recording media. The recording medium can also be a non-volatile storage device such as RAM, ROM, or HDD, which is an internal storage device included in the server device. Blu-ray is a registered trademark.

[0088] 7. Summary of the Disclosure A summary of this disclosure is provided below.

[0089] (Appendix 1) An audio output method for an audio output device, comprising: causing a processor included in the audio output device to divide audio data received from outside into predetermined size chunks to generate a plurality of partial audio data; detecting partial audio data from the plurality of partial audio data whose audio amplitude at the end of the partial audio data is greater than a predetermined range; and performing edge processing to bring the audio amplitude at the end of the detected partial audio data within the predetermined range, wherein detecting the partial audio data includes detecting partial audio data whose audio amplitude is greater than the predetermined range, targeting the partial audio data located at the end of the continuously received audio data, or, when a portion of the audio data is lost, the partial audio data before and after the lost portion of audio data.

[0090] As a result, partial audio data whose end portions have audio amplitudes greater than a predetermined range are detected from among the partial audio data, and edge processing is performed so that the audio amplitudes of the detected end portions of the partial audio data fall within the predetermined range. Therefore, noise generation can be suppressed. Furthermore, when partial audio data located at the end of continuous audio data, or when a portion of audio data is lost, partial audio data whose audio amplitudes are greater than the predetermined range are detected from the partial audio data before and after the lost portion of audio data. Therefore, the processing load on the processor can be reduced compared to when all partial audio data are processed.

[0091] (Appendix 2) The audio output method of claim 1, wherein performing the end processing includes detecting a point in time at the beginning of the detected partial audio data where the audio amplitude falls within the specified range, or a point in time at the end of the detected partial audio data where the audio amplitude falls within the specified range, and removing the partial audio data that is ahead of or behind the detected point in time.

[0092] This allows the point at which the audio amplitude falls within a predetermined range to be detected, and the audio data portion leading or trailing the detected point to be removed, thereby efficiently suppressing noise generation.

[0093] (Appendix 3) 2. The audio output method according to claim 1, wherein performing the edge processing includes gradually reducing the audio amplitude of the edge and correcting the audio amplitude so that it falls within the predetermined range.

[0094] This allows the partial audio data to be corrected so that the audio amplitude at the end portions decreases in stages, thereby making it possible to correct the audio so that it fades out when the audio data is played back.

[0095] (Appendix 4) An audio output method according to any one of appendices 1 to 3, comprising concatenating the partial audio data before and after the lost portion of audio data, and outputting the concatenated partial audio data to an audio buffer.

[0096] As a result, the partial audio data before and after the lost portion of audio data are concatenated, and the concatenated partial audio data is output to the audio buffer, allowing the partial audio data before and after the lost portion of audio data to be played back continuously.

[0097] (Appendix 5) the audio output method according to Supplementary Note 4, wherein, when connecting the previous and next partial audio data, connection points between the previous partial audio data and the next partial audio data are determined so that the phases of the previous partial audio data and the next partial audio data are continuous; if the previous partial audio data includes partial audio data after the connection point, the partial audio data after the connection point is removed from the previous partial audio data; if the next partial audio data includes partial audio data before the connection point, the partial audio data before the connection point is removed from the next partial audio data; and the previous partial audio data and the next partial audio data are connected at the connection point.

[0098] As a result, a connection point between the previous partial audio data and the subsequent partial audio data is determined so that the phases of the previous partial audio data and the subsequent partial audio data are continuous. In the previous partial audio data, the partial audio data after the connection point is removed, and in the subsequent partial audio data, the partial audio data before the connection point is removed. Then, the previous partial audio data and the subsequent partial audio data are connected at the connection point. As a result, noise is suppressed and audio data with a continuous phase can be reproduced.

[0099] (Appendix 6) A projector comprising a receiving unit that receives audio data and a processor that processes the received audio data, wherein the processor performs the following: dividing the audio data received from outside into predetermined size segments to generate a plurality of partial audio data; detecting, from among the plurality of partial audio data, partial audio data whose audio amplitude at the end of the partial audio data is greater than a predetermined range; and performing edge processing to bring the audio amplitude at the end of the detected partial audio data within the predetermined range; wherein detecting the partial audio data includes detecting partial audio data whose audio amplitude is greater than the predetermined range, from the partial audio data located at the end of the continuously received audio data, or, when a portion of the audio data is lost, from the partial audio data before and after the lost portion of audio data.

[0100] As a result, partial audio data whose end portions have audio amplitudes greater than a predetermined range are detected from among the partial audio data, and edge processing is performed so that the audio amplitudes of the detected end portions of the partial audio data fall within the predetermined range. Therefore, noise generation can be suppressed. Furthermore, when partial audio data located at the end of continuous audio data, or when a portion of audio data is lost, partial audio data whose audio amplitudes are greater than the predetermined range are detected from the partial audio data before and after the lost portion of audio data. Therefore, the processing load on the processor can be reduced compared to when all partial audio data are processed.

[0101] (Appendix 7) A program that causes a processor mounted on a computer to divide audio data received from outside into predetermined size chunks to generate a plurality of partial audio data; detect, from among the plurality of partial audio data, partial audio data whose audio amplitude at the end of the partial audio data is greater than a predetermined range; and perform edge processing to bring the audio amplitude at the end of the detected partial audio data within the predetermined range, wherein detecting the partial audio data includes detecting partial audio data whose audio amplitude is greater than the predetermined range, targeting the first or last partial audio data of the consecutive audio data, or, when a portion of the audio data is lost, the partial audio data before and after the lost portion of audio data.

[0102] As a result, partial audio data whose end portions have audio amplitudes greater than a predetermined range are detected from among the partial audio data, and edge processing is performed so that the audio amplitudes of the detected end portions of the partial audio data fall within the predetermined range. Therefore, noise generation can be suppressed. Furthermore, when partial audio data located at the end of continuous audio data, or when a portion of audio data is lost, partial audio data whose audio amplitudes are greater than the predetermined range are detected from the partial audio data before and after the lost portion of audio data. Therefore, the processing load on the processor can be reduced compared to when all partial audio data are processed. [Explanation of symbols]

[0103] 1...projection system, 10...projection surface, 100...terminal device, 110...first wireless communication I / F, 130...touch panel, 150...first control unit, 160...first memory unit, 161...OS, 163...APP, 170...first processor, 200...projector, 210 second wireless communication I / F, 220...audio driver, 225...speaker, 230...image processing unit, 235...frame memory, 240...image projection unit, 241...light source, 243...light modulation device, 245...optical unit, 250...second control unit, 260...second memory unit, 261...audio buffer, 263...firmware, 265...APP, 270...second processor, 271...buffer processing unit, 273...end processing unit.

Claims

1. The processor in the audio output device is Dividing audio data received from an external device into a predetermined size to generate a plurality of partial audio data; Detecting partial audio data from among the plurality of partial audio data, the partial audio data having an audio amplitude at an end of the partial audio data that is greater than a predetermined range; performing edge processing to bring the audio amplitude of the edge of the detected partial audio data into the predetermined range; Execute The audio output method includes detecting partial audio data whose audio amplitude is greater than the predetermined range, targeting the partial audio data located at the end of the continuously received audio data, or, when a portion of the audio data is lost, the partial audio data before and after the lost portion of audio data.

2. The performing of the edge processing includes: Detecting a time point at which the audio amplitude falls within the predetermined range at the leading end of the detected partial audio data, or a time point at which the audio amplitude falls within the predetermined range at the trailing end of the detected partial audio data, 2. The audio output method according to claim 1, further comprising the step of removing partial audio data ahead of or behind the detected point in time.

3. The performing of the edge processing includes:

2. The audio output method according to claim 1, further comprising correcting the audio amplitude at the end portion by gradually reducing the audio amplitude so that the audio amplitude falls within the predetermined range.

4. concatenating the partial audio data before and after the lost partial audio data; 2. The audio output method according to claim 1, wherein the concatenated partial audio data is output to an audio buffer.

5. When concatenating the preceding and following partial audio data, determining connection points between the previous partial audio data and the subsequent partial audio data so that the phases of the previous partial audio data and the subsequent partial audio data are continuous; If the previous partial audio data includes partial audio data after the connection point, the partial audio data after the connection point is removed from the previous partial audio data; If the subsequent partial audio data includes partial audio data before the connection point, the partial audio data before the connection point is removed from the subsequent partial audio data; 2. The audio output method according to claim 1, wherein the preceding partial audio data and the following partial audio data are connected at the connection point.

6. a receiving unit that receives audio data; a processor for processing the received audio data; A projector comprising: The processor, Dividing audio data received from an external device into a predetermined size to generate a plurality of partial audio data; Detecting partial audio data from among the plurality of partial audio data, the partial audio data having an audio amplitude at an end of the partial audio data that is greater than a predetermined range; performing edge processing to bring the audio amplitude of the edge of the detected partial audio data into the predetermined range; Execute Detecting the partial audio data includes detecting partial audio data whose audio amplitude is greater than the specified range, targeting the partial audio data located at the end of the audio data received continuously, or, when a portion of the audio data is lost, the partial audio data before and after the lost portion of audio data.

7. The processor installed in the computer Dividing audio data received from an external device into a predetermined size to generate a plurality of partial audio data; Detecting partial audio data from among the plurality of partial audio data, the partial audio data having an audio amplitude at an end of the partial audio data that is greater than a predetermined range; performing edge processing to bring the audio amplitude of the edge of the detected partial audio data into the predetermined range; Execute The program includes detecting partial audio data whose audio amplitude is greater than the predetermined range, targeting the partial audio data located at the end of the continuously received audio data, or, when a portion of the audio data is lost, the partial audio data before and after the lost portion of audio data.

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