Multiple audio source adaptive switching device and method thereof

Abstract

Multiple audio source adaptive switching device and method are provided. The method includes: receiving an audio signal; extracting a plurality of sampling points from the audio signal, where one of the plurality of sampling points is defined as a first sampling point, and the others are defined as a plurality of second sampling points; when an absolute difference between each of the plurality of second sampling points and the first sampling point exceeds a first threshold, accumulating an effective value; and when the effective value exceeds a second threshold, outputting the audio signal.

Description

[Technical Field]

[0001] This invention relates to an audio device and method, and more particularly to an device and method suitable for performing audio detection. [Previous Technology]

[0002] Most multi-screen display devices allow users to manually switch between different audio sources. For example, users can manually switch between multiple audio sources through an on-screen display (OSD) menu; or they can switch audio sources through software settings; or they can switch audio sources through hardware buttons on the display device.

[0003] While the manual switching method is quite intuitive for users, it still has shortcomings. For example, when multiple screens are displayed on the same monitor, and the screen menu sets a specific screen as the audio source, even if there is no actual audio playback requirement for that specific screen, the user must manually switch to receive the call request or other notification tone when another screen displays such a tone, thus failing to receive these audio signals in real time. Another example is if the current screen is playing an audio signal. After the user manually switches to another screen, the display device cannot automatically switch the audio signal source back to the original screen to continue playback, requiring the user to manually switch again. [Summary of the Invention]

[0004] In view of this, the applicant proposes a multi-source audio adaptive switching method, comprising: receiving an audio signal; extracting multiple sampling points from the audio signal, wherein one of the multiple sampling points is defined as a first sampling point and the rest are defined as multiple second sampling points; when it is determined that the absolute difference between each of the second sampling points and the first sampling point is greater than a first threshold, accumulating an effective value; and when it is determined that the effective value is greater than a second threshold, outputting the audio signal.

[0005] The applicant also proposes a multi-source audio adaptive switching device, comprising a multiplexer and an audio detector. The multiplexer is used to receive multiple audio signals and output one of the multiple audio signals; and the audio detector is used to: receive one of the audio signals; extract multiple sampling points from the one audio signal, one of the multiple sampling points is defined as a first sampling point, and the rest are defined as multiple second sampling points; when it is determined that the absolute difference between each of the second sampling points and the first sampling point is greater than a first threshold, accumulate an effective value; and when it is determined that the effective value is greater than a second threshold, output the one audio signal.

Implementation Method

[0006] Figure 1 is a block diagram of a multi-source audio adaptive switching system according to some embodiments. Please refer to Figure 1. In this embodiment, the multi-source audio adaptive switching system 10 includes a multi-source audio adaptive switching device 11, a playback device 12, and multiple signal sources, namely a first signal source 131, a second signal source 132, and an Nth signal source 133. The multiple signal sources are respectively coupled to the multi-source audio adaptive switching device 11, and the multi-source audio adaptive switching device 11 is coupled to the playback device 12. The coupling allows information transmission between the devices, which is not limited to direct connection or indirect connection through other systems, modules, devices, or components, nor is it limited to wired connection or wireless connection. In this embodiment, the first signal source 131 sends audio signal A1 and video signal V1 to the multi-source audio adaptive switching device 11, the second signal source 132 sends audio signal A2 and video signal V2 to the multi-source audio adaptive switching device 11, and the Nth signal source 133 sends audio signal A3 and video signal V3 to the multi-source audio adaptive switching device 11.

[0007] Multiple signal sources can refer to two or more signal sources; in other words, the Nth signal source 133 may not exist. The audio signals A1, A2, A3 and video signals V1, V2, V3 transmitted by the signal sources correspond to each other. For example, video signal V1 corresponds to audio signal A1. For instance, video signal V1 is a scene from a play, and audio signal A1 is the sound synchronized with the scene; or, video signal V1 is a pop-up notification window, and audio signal A1 is a telephone ringtone. Multiple signal sources are not limited to distinctions based on physical devices or software interfaces. For example, the first signal source 131 is a TV box, and the second signal source 132 is the user's mobile phone. Another example is that the first signal source 131 is a video website, and the second signal source 132 is communication software. Yet another example is that the first signal source 131 is the first webpage address of a video website, and the second signal source 132 is the second webpage address of a video website.

[0008] The communication interface used by the signal source of the physical device can be Ethernet interface, audio cable / port, bus, Digital Visual Interface (DVI), Video Graphics Array (VGA), Musical Instrument Digital Interface (MIDI), USB-A (Universal Serial Bus Type-A), USB-B, USB-C, Micro USB, Mini USB, USB 2.0, USB 3.0, Lightning, HDMI-A (High-Definition Multimedia Interface Type-A), HDMI-B, HDMI-C, HDMI-D, DisplayPort (DP), and the multi-source audio adaptive switching device 11 can include input ports of one or more communication interfaces. The signal source of the software interface can be a website page, an application, or a foreground / background application.

[0009] In this embodiment, the playback device 12 includes an audio receiver 121 and a video receiver 122. The audio receiver 121 is coupled to the audio detector 112, and the video receiver 122 is coupled to the video transmitter 113. The playback device 12 can be a display system, including a screen and a speaker. The speaker can be independent or integrated into the screen. In some embodiments, the playback device 12 can divide the user interface 123 into multiple sub-interfaces according to multi-task processing (MTP), such as windows, pagination, picture-by-picture (PBP), picture-in-picture (PIP), OSD, or partitioned screens. Each sub-interface can correspond to a signal source.

[0010] In this embodiment, the multi-source audio adaptive switching device 11 includes a multiplexer 111, an audio detector 112, and a video transmitter 113. The multiplexer 111 is coupled to the audio detector 112, and the audio detector 112 is coupled to the video transmitter 113. The multiplexer 111 is used to receive multiple audio signals, such as audio signals A1, A2, and A3, and output one of the multiple audio signals A1, A2, and A3 to the audio receiver 121 of the playback device 12. The multiple signal sources can be digital signal sources or analog signal sources. In some embodiments, the multi-source audio adaptive switching device 11 may include a line-in port to receive external audio sources. Furthermore, the multi-source audio adaptive switching device 11 may further include an analog-to-digital converter (not shown) coupled between the signal source and the multiplexer 111, or coupled between the multiplexer 111 and the audio detector 112. In some embodiments, the multiplexer 111 can cyclically switch within the acquisition range formed by multiple signal sources to receive multiple audio signals A1, A2, A3. For example, the first signal source 131, the third signal source (not shown), and the sixth signal source (not shown) simultaneously emit audio signals, and the multiplexer 111 switches to the first signal source 131 at a first time point, switches to the third signal source at a second time point, switches to the sixth signal source at a third time point, switches to the first signal source 131 at a fourth time point, and so on.

[0011] The audio detector 112 can be used to execute the multi-source audio adaptive switching method of one or more embodiments of this disclosure. The video transmitter 113 is used to receive multiple video signals, such as video signals V1, V2, V3, and output one or more video signals V1, V2, V3 to the video receiver 122 of the playback device 12. The audio detector 112 and the video transmitter 113 can be implemented by an integrated or separate processor, which can be a SoC chip, a central processing unit (CPU), a micro-controller unit (MCU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or logic circuits.

[0012] Figure 2 is a flowchart of a multi-source audio adaptive switching method according to some embodiments. To facilitate understanding of the possible operation of the audio detector 112 and the video transmitter 113, Figure 2 presents one embodiment of the multi-source audio adaptive switching method (hereinafter referred to as the "switching method"). It should be understood that other configurations that modify, omit, and refine the flowcharts of the various embodiments are contemplated without departing from the spirit and scope of this disclosure.

[0013] In this embodiment, the switching method obtains the number of signal sources (step S1) and switches the signal sources one by one (step S2). In some embodiments, the video transmitter 113 receives multiple video signals V1, V2, V3, and defines the range and number of signal sources according to the sources of the received video signals V1, V2, V3. For example, if the video transmitter 113 only receives video signals V1 and V2 but not video signal V3, it is determined that the capture range of the signal sources is the first signal source 131 and the second signal source 132, and the number of signal sources is 2. Since each video signal V1, V2 corresponds to each audio signal A1, A2, when the existence of video signals V1, V2 is confirmed, the capture range of each audio signal A1, A2 is also defined. In this embodiment, the video transmitter 113 can send the capture range to the audio detector 112. The audio detector 112 can sort multiple audio signals within the capture range and control the multiplexer 111 to cyclically switch within the capture range to receive multiple audio signals. Therefore, the audio detector 112 can control the multiplexer 111 to cyclically switch within the capture range formed by audio signals A1 and A2, regardless of whether the output state of audio signals A1 and / or A2 is valid or invalid when the switching method determines that video signals V1 and V2 exist. In other embodiments, the multiplexer 111 can also switch between all audio input terminals of the multi-source audio adaptive switching device 11 (e.g., the audio input terminals of audio signals A1, A2, and A3 shown in FIG1), in which case step S1 can be omitted. The switching method can determine the presence status of video signals V1, V2, and V3 based on the signal pin potential changes at the video input terminal, the hot-plug detection (HPD) signal, the request signal sent by the signal terminal, or the clock signal.

[0014] In step S3, the method is switched to decrypt the audio packets. In some embodiments, the audio detector 112 can decrypt the audio signals A1, A2, A3 according to the communication interface protocol corresponding to the signal source to obtain the data of the audio signals A1, A2, A3. In addition to the data, the packets may also include sampling rate, compression rate, number of channels, sequence number, synchronization bits, mute status, or encoding format. For example, the audio format is set according to the digital audio interface requirements of IEC60958. In other embodiments, the audio signal is an analog signal, and step S3 can be omitted. Figure 4A is a timing data waveform diagram of the audio signal according to some embodiments. Please refer to Figure 2 and Figure 4A together. Figure 4A shows the timing data of the audio signals A1, A2, A3. The horizontal axis represents time, and the vertical axis represents the amplitude (voltage or data point) of the timing data 91. In some embodiments, the switching method can obtain the original sampling rate by reading the sampling rate of the data within the packet (step S4). In other embodiments, the switching method can obtain the original sampling rate by detecting timing data 91 (step S4). For example, the audio detector 112 can perform Audio Frequency Detection (AFD) to determine the frequency components of the data to estimate the original sampling rate. After confirming the number of channels of the current audio signal (e.g., stereo or multi-channel), the AFD calculates the number of packets received per unit time to estimate the original sampling rate. In other embodiments, the original sampling rate can also be estimated using Fast Fourier Transform (FFT), bandpass filtering, or autocorrelation analysis. For example, the audio detector 112 performs an FFT on the data to be tested to obtain the peak frequency, calculates the product of the peak frequency and the number of FFT sample points, and estimates the original sampling rate by dividing by an integer. In other embodiments, the multi-source audio adaptive switching device 11 uses an analog-to-digital converter to sample the analog audio signal, and the switching method obtains the original sampling rate according to the sampling rate setting of the analog-to-digital converter (step S4).

[0015] In step S5, the switching method determines whether the original sampling rate is 0. For example, if the audio output of the signal source is not connected to the audio input of the multi-source audio adaptive switching device 11, or the audio source of the signal source is damaged, or the signal source only has a video source, then the audio detector 112 determines that the original sampling rate should be 0. When the switching method determines that the original sampling rate is 0 (step S5, determined to be "yes"), it returns to step S2 to switch to the next signal source within the capture range, and performs steps S2 to S5 for the next audio signal A1, A2, A3. In some other embodiments, when step S5 determines to be "yes", the audio detector 112 notifies the video transmitter 113 to acquire the number of signal sources again (step S1) to redefine the capture range. When the switching method determines that the original sampling rate is not 0 (step S5, determined to be "no"), it detects the validity of the audio (step S6).

[0016] Figure 3 is a flowchart of the audio validity detection step of the multi-source audio adaptive switching method according to some embodiments; Figure 4B is a waveform diagram of the timing data of the audio signal after taking the absolute value according to some embodiments. Please refer to Figures 3, 4A and 4B together. In step S61, the switching method takes the absolute value of the audio. For example, binary complement processing is performed on the data data with a sign bit of 1. Figures 4A and 4B show the data data with the original value being negative by dashed lines. The timing data 91 in Figure 4A is shown as timing data 92 in Figure 4B after taking the absolute value. In this embodiment, the peak values ​​of timing data 92 are all positive, which is beneficial for the audio detector 112 to compare the relative intensity of each data point on timing data 92.

[0017] Figure 4C is a waveform diagram of the timing data of the audio signal to be sampled according to some embodiments. Please refer to Figures 3 and 4C together. The switching method samples multiple sampling points from the audio (step S62), wherein the switching method samples one group of sampling points within the sampling range T1, another group of sampling points within the sampling range T2, and yet another group of sampling points within the sampling range T3. The starting point of the sampling range T1 is time point t1, the starting point of the sampling range T2 is time point t2, the starting point of the sampling range T3 is time point t3, and the sampling method after time point t4 follows the same pattern. In this embodiment, the ending point of the sampling range T1 is the same as the starting point of the sampling range T2, i.e., time point t1. In other embodiments, the two time points may also be different, that is, there may be a time interval between each sampling range. The sampling range can be a moving time pane to sample multiple sampling points within a similar time range. In some embodiments, the timing data 92 itself is a digital signal containing multiple sampling points, and the switching method samples all sampling points within the sampling range T1. For example, when the original sampling rate of the timing data 92 is 48kHz and the sampling range T1, T2, T3 is 20 milliseconds, the switching method can capture 960 sampling points within the sampling range T1. In other words, in some embodiments, the sampling rate of the audio detector 112 can be set to be less than or equal to the original sampling rate of the timing data 92.

[0018] Subsequently, the switching method sets a baseline (step S63). In the embodiment of FIG4C, the switching method samples 256 sampling points within the sampling range T1, and selects the amplitude of one sampling point (hereinafter referred to as the "first sampling point") from the 256 sampling points as the amplitude of the baseline. In this embodiment, the switching method uses the starting point of each sampling range as the first sampling point. Therefore, the amplitude of the time series data 92 at time point t1 is set as the baseline BT1, the amplitude of the time series data 92 at time point t2 is set as the baseline BT2, and the amplitude of the time series data 92 at time point t3 is set as the baseline BT3. In other embodiments, any sampling point within the sampling range T1 can be used as the first sampling point. As shown in FIG4C, the amplitudes of the baselines BT1, BT2, and BT3 can fluctuate, depending on the amplitude of the first sampling point.

[0019] In step S64, the switching method compares the absolute difference between each sampling point and the baseline. For example, among the 256 sampling points within the sampling range T1, one sampling point is designated as the first sampling point, and the absolute difference between the amplitudes of the remaining 255 sampling points (hereinafter referred to as "second sampling points") and the amplitude of the first sampling point is taken, i.e., the absolute value is obtained by subtracting them. Then, the switching method determines whether the absolute difference is greater than the first threshold TH1 (step S65). When the switching method determines that the absolute difference between any second sampling point and the first sampling point is less than the first threshold TH1, it indicates that this second sampling point is invalid. The first threshold TH1 reflects the permissible variation between the sampling points of the time series data 92, or more precisely, it reflects the permissible variation between the second sampling point and the first sampling point. As shown in Figure 4C, dashed lines are drawn above and below the baselines BT1, BT2, BT3, which are separated from the baselines BT1, BT2, BT3 by the first threshold TH1. For example, even in silent mode, the signal source may still output timing data 92 with an amplitude of 0. This timing data 92 is still sampled according to the preset original sampling rate; therefore, step S5 determines "No". However, the audio signals A1, A2, and A3 may still be determined as invalid audio signals. The first threshold TH1 can be defined based on the allowable amplitude variation of invalid audio signals or based on the minimum amplitude variation of valid audio signals.

[0020] When the switching method determines that the absolute difference is greater than the first threshold TH1 (step S65, determined to be "yes"), the effective values ​​are accumulated (step S66). For example, if the amplitude of the first sampling point is 60, and the amplitudes after the second sampling point are [57, 32, 72, 8, 66, 105] in sequence, and the first threshold TH1 is 10, then the effective values ​​after the second sampling point are [0, 1, 2, 3, 3, 4] in sequence, where the effective value of 4 indicates that 4 out of the 6 second sampling points are effective. In this embodiment, the effective value refers to a valid integer value. In other embodiments, the effective value refers to an effective proportion value, and its numerator and denominator can be accumulated separately. For example, the effective value can refer to the ratio of valid second sampling points to invalid second sampling points within the sampling range T1, T2, T3. The effective values ​​would then be [0 / 1, 1 / 1, 2 / 1, 3 / 1, 3 / 2, 4 / 2], or [0, 1, 2, 3, 1.5, 2]. As another example, the effective value can refer to the ratio of valid second sampling points to all sampling points within the sampling range T1, T2, T3. The effective values ​​would then be [0 / 256, 1 / 256, 2 / 256, 3 / 256, 3 / 256, 4 / 256].

[0021] When the accumulation of valid values ​​is completed (step S66), or when the switching method determines that the absolute difference is not greater than the first threshold TH1 (step S65, determined to be "No"), the switching method determines whether all sampling points have been compared (step S67). When the switching method determines that all sampling points have not been compared (step S67, determined to be "No"), it returns to step S64 to compare the next second sampling point; when the switching method determines that all sampling points have been compared (step S67, determined to be "Yes"), the audio validity detection procedure is completed (step S68).

[0022] Based on the valid value generated in step S6, the switching method determines whether the valid value is greater than the second threshold (step S7). In this embodiment, when the switching method determines that the valid value is not greater than the second threshold (step S7, determined to be "No"), it returns to step S2 to switch to the next signal source within the acquisition range, and performs steps S2 to S7 for the next audio signal A1, A2, A3. In other embodiments, when step S7 is determined to be "No", the audio detector 112 notifies the video transmitter 113 to acquire the number of signal sources again (step S1) to redefine the acquisition range. When the switching method determines that the valid value is greater than the second threshold (step S7, determined to be "Yes"), it outputs audio (step S8). The second threshold can reflect the allowable value of the number of valid or invalid sampling points within the sampling range T1, T2, T3.

[0023] The following describes possible applications of the multi-source audio adaptive switching system 10 according to different embodiments. It should be understood that other use cases are contemplated by modifying, substituting, repurposing, and simplifying the possible applications of the various embodiments without departing from the spirit and scope of this disclosure.

[0024] In some embodiments, referring to FIG1, the playback device 12 executes PBP mode, and the user watches a video through the first screen, while the background program of the second screen includes communication software. Therefore, the first signal source 131 corresponds to the first screen (the video signal V1 and the audio signal A1 may come from a video website), and the second signal source 132 corresponds to the second screen (the video signal V2 and the audio signal A2 may come from the communication software or other foreground / background programs). At this time, the communication software of the second screen suddenly pops up a call notification, and the audio detector 112 detects that the audio signal A2 of the second screen is valid, and outputs the audio signal A2 of the second screen to the playback device 12. FIG5 is a block diagram of a multi-source audio adaptive switching system according to some other embodiments, please refer to FIG5. The playback device 12 includes an audio receiver 121, a video receiver 122, and a user interface 123. The audio detector 112 is coupled to the user interface 123, so as to receive user control signals or send user notification signals. In this embodiment, the audio detector 112 can determine whether to output the audio signal A2 of the second screen to the playback device 12 in response to the logical value of the user control signal (selecting / not selecting to answer the call). In another embodiment, if the audio detector 112 detects that the audio signal A2 of the second screen is valid, it sends a user notification signal to the user interface 123, and the playback device 12 generates a pop-up notification window. The audio detector 112 can determine whether to output the audio signal A2 of the second screen to the playback device 12 in response to the logical value of the user clicking the notification window (switching / not switching the audio source).

[0025] In some embodiments, when a user watches a video through the first screen in PBP mode and makes a call using communication software through the second screen, the call on the second screen ends, and the audio detector 112 detects that the effective value of the audio signal A2 on the second screen has switched and is less than the second threshold. In this embodiment, when the audio detector 112 determines that the currently output audio signal A2 is invalid, it re-executes the switching method (e.g., steps S1 to S8, or steps S2 to S8). At this time, the audio detector 112 detects that the audio signal A1 on the first screen is valid and outputs the audio signal A1 on the first screen to the playback device 12. Similarly, the audio detector 112 can respond to the logical value of the user control signal (switch / not switch audio source) to determine whether to output the audio signal A1 on the first screen to the playback device 12. Alternatively, in another embodiment, the audio detector 112 may determine whether to output the audio signal A1 of the first screen to the playback device 12 in response to the user's control signal selection value (selecting the first screen / second screen, such as clicking or moving the cursor to the screen).

[0026] In some embodiments, referring to FIG1, the playback device 12 executes PIP mode, whereby the user watches the first video through the master screen and the second video through the sub-screen. Therefore, the first signal source 131 corresponds to the master screen (video signal V1 and audio signal A1 may come from the first URL of the video website), and the second signal source 132 corresponds to the sub-screen (video signal V2 and audio signal A2 may come from the second URL of the video website). At this time, the user enlarges the sub-screen through the user interface 123 to replace the master screen, and the multi-source audio adaptive switching device 11 receives the control command and interrupts the reception of the first signal source 131. At this time, the audio detector 112 detects that the audio signal A1 of the first signal source 131 is invalid, and the switching method can be re-executed.

[0027] In some embodiments, the multiple audio signals A1, A2, A3 within the capture range include a primary audio signal and a secondary audio signal. When the output of the secondary audio signal is determined to be greater than a second threshold, the primary audio signal is output. For example, in PIP mode, the main screen corresponds to the primary audio signal, and the child screen corresponds to the secondary audio signal. At this time, the audio detector 112 detects that the effective values ​​of both the primary and secondary audio signals are greater than the second threshold, and outputs the primary audio signal. At this time, when the audio detector 112 determines that the effective value of the primary audio signal has switched and is less than the second threshold (e.g., the user mutes the main screen), the switching method is re-executed. When the audio detector 112 determines that the effective value of the secondary audio signal is greater than the second threshold, the output audio signal is switched from the primary audio signal to the secondary audio signal. In some embodiments, the audio detector 112 continuously executes the switching method while audio signals A1, A2, A3 are being output. When the valid value of the primary audio signal is determined to be greater than the second threshold (e.g., the user unmutes the main screen), the output audio signal is switched from the secondary audio signal to the primary audio signal.

[0028] In some embodiments, the primary audio signal is defined according to the selection signal. For example, a user controls the cursor to click or move to the screen corresponding to one of the video signals V1, V2, V3 through the user interface 123 to generate a selection value. The user interface 123 generates a control signal containing the selection value and sends it to the audio detector 112. The audio detector 112 can define the corresponding audio signal A1, A2, A3 as the primary audio signal in response to the selection value of the user's control signal. Alternatively, the user can designate any audio signal A1, A2, A3 generated by any signal source as the primary audio signal through the user interface 123 and send a control signal containing the selection value to the audio detector 112. In some embodiments, the primary audio signal is defined according to the input of the multi-source audio adaptive switching device 11. For example, the multi-source audio adaptive switching device 11 may include multiple digital input terminals and an external audio source port input terminal. The audio signals A1, A2, and A3 received by the external audio source port input terminal can be defined as the primary audio signals, and the other digital input terminals can be defined as secondary audio signals. Alternatively, the multi-source audio adaptive switching device 11 may include multiple digital input terminals, and the audio signals A1, A2, and A3 received by any one of them can be defined as the primary audio signals.

[0029] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the art may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended patent application. [Simplified Explanation of the Diagram]

[0030] Figure 1 is a block diagram of a multi-source audio adaptive switching system according to some embodiments. Figure 2 is a flowchart of a multi-source audio adaptive switching method according to some embodiments. Figure 3 is a flowchart of the audio validity detection step of the multi-source audio adaptive switching method according to some embodiments. Figure 4A is a waveform diagram of timing data of an audio signal according to some embodiments. Figure 4B is a waveform diagram of the timing data of an audio signal after taking the absolute value according to some embodiments. Figure 4C is a waveform diagram of the timing data of an audio signal to be sampled according to some embodiments. Figure 5 is a block diagram of a multi-source audio adaptive switching system according to other embodiments.

Claims

1. A multi-source audio adaptive switching method, comprising: receiving an audio signal; sampling multiple sampling points from the audio signal, wherein one of the multiple sampling points is defined as a first sampling point and the rest are defined as multiple second sampling points; when it is determined that the absolute difference between each of the second sampling points and the first sampling point is greater than a first threshold, accumulating an effective value; and when it is determined that the effective value is greater than a second threshold, outputting the audio signal.

2. The multi-source audio adaptive switching method as described in claim 1 further includes receiving multiple audio signals, the multiple audio signals including a main audio signal and a secondary audio signal, and determining that the effective value of the main audio signal is greater than the second threshold during the output of the secondary audio signal, and outputting the main audio signal.

3. The multi-source audio adaptive switching method as described in claim 2 further includes: receiving multiple video signals, each video signal corresponding to a specific audio signal; receiving a selection signal specifying one of the video signals included in the multiple video signals; and defining the main audio signal according to the audio signal corresponding to the one video signal.

4. The multi-source audio adaptive switching method as described in claim 1 further includes: receiving multiple audio signals; and determining, during the output of one of the multiple audio signals, that the effective value of the one audio signal is less than the second threshold, receiving another of the multiple audio signals and determining the effective value of the other audio signal.

5. The multi-source audio adaptive switching method as described in claim 4 further includes: receiving multiple video signals, each video signal corresponding to a specific audio signal; defining the existence state of each audio signal based on each of the multiple video signals to define an acquisition range of the multiple audio signals; and cyclically switching within the acquisition range to receive the multiple audio signals.

6. The multi-source audio adaptive switching method as described in claim 1 further includes: receiving multiple audio signals; detecting the original sampling rate of one of the audio signals; and when it is determined that the original sampling rate of one of the audio signals is zero, receiving another of the multiple audio signals and determining the original sampling rate of the other audio signal.

7. The multi-source audio adaptive switching method as described in claim 1 further includes sampling the plurality of sampling points from the audio signal according to a moving time pane, wherein the first of the plurality of sampling points is defined as the first sampling point, and the remainder are defined as the plurality of second sampling points.

8. A multi-source audio adaptive switching device, comprising: a multiplexer for receiving multiple audio signals and outputting one of the multiple audio signals; and an audio detector for: receiving one of the audio signals; sampling multiple sampling points from the one audio signal, wherein one of the multiple sampling points is defined as a first sampling point and the remainder is defined as multiple second sampling points; accumulating an effective value when the absolute difference between each of the second sampling points and the first sampling point is greater than a first threshold; and outputting the one audio signal when the effective value is greater than a second threshold.

9. The multi-source audio adaptive switching device as described in claim 8 further comprises: a video transmitter for: receiving multiple video signals, each video signal corresponding to a specific audio signal; defining the existence state of each audio signal based on each of the multiple video signals to define a capture range of the multiple audio signals; and sending the capture range to the audio detector; and the audio detector is further configured to: cyclically switch within the capture range to receive the multiple audio signals.

10. The multi-source audio adaptive switching device as described in claim 8 further comprises: a user interface for receiving a selection signal; a video transmitter for: receiving multiple video signals, each video signal corresponding to a specific audio signal; receiving the selection signal, the selection signal specifying one of the video signals included in the multiple video signals; defining a master audio marker for the audio signal corresponding to the one video signal; and sending the master audio marker to the audio detector; and the audio detector is further configured to: define a master audio signal and a secondary audio signal other than the master audio signal within the multiple audio signals based on the master audio marker; and determine, during the output of the secondary audio signal, that the effective value of the master audio signal is greater than the second threshold, and output the master audio signal.

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