TWI448108B - System and method for video conference - Google Patents

Description

Video conferencing system and method

The present invention relates to a video conferencing system and method.

The phone has been a very important communication tool since its invention. The traditional telephone transmits the switch to the public switched telephone network (PSTN) by converting the telephone number of the receiving end and sending a series of dual-tone multi-frequency (DTMF) signals to the switch. The DTMF signal knows the location of the receiving end and establishes a call setup, after which the two ends can make a call. The basis for the establishment of the connection is the DTMF signal, and the various services attached by the telecommunication service provider are also after the connection is established, the user presses the extra numeric button, and then the corresponding DTMF signal is sent by the phone to the server for conversion. The corresponding service is available. Therefore, DTMF signals play an important role in the entire telecommunications network.

However, with the rapid development of the Internet, VoIP has gradually replaced the traditional way of talking. That is to say, the basis of the connection establishment has been changed from the telephone number of the converted receiving terminal to the DTMF signal to obtain the Internet Protocol (IP) address of the receiving end and establish a connection through the Internet. The traditional telephone connected to the Internet telephony or the Universal Serial Bus (USB) telephone adapter has evolved into a tool for inputting IP addresses using digital buttons, and the DTMF signal becomes a simple digital signal.

The present disclosure relates to a video conferencing system and method for converting a string command corresponding to a dual tone multi-frequency signal into a keyboard button action to control an application, and detecting and eliminating a dual tone multi-frequency signal in the audio signal, Avoid system control interference and apply to video conferencing.

According to a first aspect of the present disclosure, a video conferencing system is provided, including a telephone, a telephone adapter, and a network communication device. The phone is used to generate a first dual tone multi-frequency signal. The telephone adapter is connected to the phone, and is configured to detect the first dual tone multi-frequency signal and generate a first command string accordingly. The network communication device is connected to the telephone adapter and a network, and is configured to convert the first command string into a first keyboard button action according to a button conversion table to control an application. The network communication device is further configured to receive a first audio signal via the network, and detect whether the first audio signal includes a second dual tone multi-frequency signal. If the first audio signal includes the second dual tone multi-frequency signal, the network communication device is further configured to mute the portion of the first audio signal corresponding to the second dual tone multi-frequency signal according to the detected result, and to mute the signal. The processed first audio signal is output to the telephone via the telephone adapter.

According to a second aspect of the present disclosure, a video conferencing method is provided for use in a video conferencing system, the video conferencing system including a telephone, a telephone adapter, and a network communication device. The telephone adapter is connected to the telephone, and the network communication device is connected to the telephone adapter and the network. The video conferencing method includes the following steps. A first dual tone multi-frequency signal is generated by using the phone. The first dual tone multi-frequency signal is detected by the telephone adapter and a first command string is generated accordingly. The network communication device converts the first command string into a first keyboard button action according to a button conversion table to control an application. The network communication device receives a first audio signal via the network, and detects whether the first audio signal includes a second dual tone multi-frequency signal. If the first audio signal includes the second dual-tone multi-frequency signal, the network communication device mutes the portion of the first audio signal corresponding to the second dual-tone multi-frequency signal according to the detected result, and the mute processing is performed. The first audio signal is output to the phone via the telephone adapter.

In order to better understand the above and other aspects of the present disclosure, an embodiment will be described hereinafter with reference to the accompanying drawings.

The video conferencing system and method proposed by the present disclosure converts a string command corresponding to a dual tone multi-frequency signal into a keyboard button action to control an application, and detects and eliminates a dual tone multi-frequency signal in the audio signal, thereby avoiding System control is interfered with for video conferencing.

Please refer to FIG. 1 , which is a block diagram of a video conferencing system in accordance with an embodiment. The video conferencing system 100 includes a telephone 110, a telephone adapter 120, and a network communication device 130. The telephone adapter 120 is connected to the telephone 110; the network communication device 130 is connected to the telephone adapter 120 and a network (not shown). The network communication device 130 is, for example, a host or a set-top box, which is connected to the telephone adapter 120 by, for example, a universal serial bus (USB), but is not limited. The network communication device 130 includes a network module 140 and an audio module 150. The network module 140 is used to establish communication with the network, so that the audio signals and video signals related to the video conference can be received or transmitted. The network communication device 130 can substantially receive the audio signal from the phone 110 or receive the audio signal related to the far-end video conference from the network.

The audio module 150 includes a dual-tone multi-frequency (DTMF) signal forwarding module 162, a keyboard event launcher 164, and a dual-tone multi-frequency elimination (elimination). The module 166, an audio output module 168 and an audio input module 169. The audio output module 168 is, for example, a headphone. The audio input module 169 is a physical device connected to the device, for example, a microphone. The audio input module 169 can receive an audio packet from the network to obtain an audio signal. In this embodiment, after the connection of the video conference is established, the phone 110 can be used as a controller to control the local application through the phone adapter 120 and the network communication device 130. Please refer to FIG. 2A and FIG. 2B simultaneously, which respectively illustrate a partial flow chart of a video conference method according to an embodiment. The video conferencing methods respectively shown in FIG. 2A and FIG. 2B may be performed simultaneously, or may be continuous behaviors, and are not limited. In step S200 of FIG. 2A, the digital button of the phone 110 is pressed to generate a first dual tone multi-frequency signal. In step S210, the phone adapter 120 detects the first dual tone multi-frequency signal and generates a first command string accordingly.

In step S220, the dual command signal forwarding module 162 receives 120 the first command string from the phone adapter and forwards the first command string to the keyboard event transmitter 164. In step S230, the keyboard event transmitter 164 converts the first command string into the first keyboard button according to a button conversion table, and the application of the local end performs the corresponding processing after receiving the first keyboard button action. Work changes the user interface, so the phone 110 can be used as a controller to control the local application. Please refer to FIG. 3 , which illustrates a schematic diagram of a key conversion table according to an embodiment. In Figure 3, different phone numeric buttons correspond to different keyboard button actions. For example, the phone number button "01" corresponds to the keyboard action "Tab", and the phone number button "08" corresponds to the keyboard action "Down". In addition, a single phone number button can also be assigned to the combination key action, but it is not limited, depending on the design requirements.

When the video conference is in progress, if the remote user simultaneously makes a call and uses the phone to control the operating system, the local videoconferencing system 100 also hears the video signal and the audio signal related to the video conference when receiving the video conference from the network. The button audio output of the terminal, that is, the audio signal received by the network module 140 from the network may include the dual-tone multi-frequency signal sent by the remote end, which may cause the telephone adapter 120 to generate a false positive, so that the network communication device 130 generates The error control of the local application occurs. Therefore, in step S240 of FIG. 2B, the network communication device 130 receives a first audio signal via the network by using the network module 140. The first audio signal is a video conference related audio signal from a remote end. The first audio signal is sampled by pulse code modulation (PCM) before being transmitted, and then compressed and cut into a plurality of first audio packets for transmission, wherein the pulse code sampling frequency per second is, for example, 8000 Hz. The network communication device 130 analyzes and decompresses the plurality of first audio packets to obtain a pulse code modulated sound segment, and thus the first audio signal includes a plurality of first audio segments.

Then, in step S250, the audio input module 169 detects whether the first audio signal includes a second dual tone multi-frequency signal. The audio input module 169 actually detects one of the DTMF flags of each of the first audio segments. If the flag is set to a false value (False), the first audio segment does not need to be detected but can be directly Is played; if the flag is set to true (True), the first audio segment needs to be detected before it can be played. The audio input module 169 has a buffer whose size is, for example, 10k to 64k bytes.

The audio input module 169 has a first buffer TMP_LINKED_LIST and a second buffer Buffer. Please refer to FIG. 4 , which is a schematic diagram of a first buffer and a second buffer of an audio input module according to an embodiment. In FIG. 4, a plurality of first audio segments (for example, α ₀ to α ₃ ) whose flags are set to true values are sequentially copied and temporarily stored in the first buffer TMP_LINKED_LIST. When the data length of the plurality of first audio segments in the first buffer TMP_LINKED_LIST is greater than a maximum detection length MaxDetectionLength, the plurality of first audio segments in the first buffer TMP_LINKED_LIST are sent to the second buffer Buffer and merged. A corresponding displacement value Offset is obtained, and the displacement value Offset is a remainder divided by a data length of the plurality of first audio segments in the first buffer TMP_LINKED_LIST and a maximum detection length MaxDetectionLength.

The audio input module 169 cooperates with the displacement value Offset to detect whether the plurality of first audio segments in the second buffer Buffer include the second dual tone multi-frequency signal. That is, the audio input module 169 detects the content of the corresponding position 0 to the position MaxDetectionLength in the second buffer Buffer, and additionally detects the content of the corresponding position Offset to the position (MaxDetectionLength+Offset) in the second buffer Buffer. In addition, the audio input module 169 further detects whether the plurality of first audio segments in the second buffer Buffer include the second dual tone multi-frequency signal, and the number K of repeated detections is substantially one of the phones 110 per second. The pulse code modulation sampling frequency (for example, 8000 Hz), the maximum detection length MaxDetectionLength, and a delay range constant DelayConstant, for example, the following formula (1), which can be optimized by adjusting the delay range constant DelayConstant The number of times of repeated detection K.

K=ceil(8000/MaxDetectionLength)/DelayConstant (1)

If the audio input module 169 detects that the plurality of first audio segments in the second buffer buffer include the second dual tone multi-frequency signal, then in step S260, the dual tone multi-frequency cancellation module 166 sets the first audio signal. The part corresponding to the second dual tone multi-frequency signal is muted. The dual tone multi-frequency cancellation modulo 166 substantially sets a plurality of first audio segments in the second buffer Buffer to a value of 0, that is, the first audio segments α ₀ to α ₃ are all filled with a value of zero. The time length SkipCount of the plurality of first audio segments set to a value of 0 may be substantially a delay basic unit DelayEquivalent, one pulse per second of the phone 110, and the maximum detection length MaxDetectionLength. Determined, for example, the following formula (2).

SkipCount=ceil(8000/MaxDetectionLength)×DelayEquivalent (2).

After the step S260, the first audio signal that has been muted by the dual-tone multi-frequency cancellation module 166 is output to the audio output module 168, or is muted by the dual-tone multi-frequency cancellation module 166. The first audio signal is output to the phone 110 via the phone adapter 120 for playback. In step S250, if the audio input module 169 does not detect that the plurality of first audio segments in the second buffer buffer include the second dual tone multi-frequency signal, then in step S280, the first audio segments are Will be played directly.

The above steps S240-S280 are used for the videoconferencing system 100 of the local end to filter out the button sound output (ie, the dual-tone multi-frequency signal) in the audio signal related to the video conference received from the remote end when the video conference is in progress. This prevents the network communication device 130 from generating an error to control the local end application. Further, when the videoconferencing system 100 of the local end outputs the audio signal related to the video conference, the button sound output in the audio signal may be filtered out first to prevent the remote terminal from malfunctioning.

In step S300, the audio input module 169 or the phone 110 generates a second audio signal. In step S310, the audio input module 169 detects whether the second audio signal includes a third dual tone multi-frequency signal. If the second audio signal includes the third dual tone multi-frequency signal, then in step S320, the dual tone multi-frequency cancellation module 166 converts the third audio to the third audio signal according to the result detected by the phone adapter 120. The part of the frequency signal is muted, and the second audio signal after the mute processing is output to the network via the network module 140. The principle that the audio input module 169 detects the dual-tone multi-frequency signal and the dual-tone multi-frequency cancellation module 166 to eliminate the dual-tone multi-frequency signal is detailed in the related contents of steps S250 and S260, so it is not heavy here. Said. If the second audio signal does not include the third dual tone multi-frequency signal, then in step S330, the second audio signal is directly output to the network via the network module 140. In this way, when the local videoconferencing system 100 can output the audio signal related to the video conference that does not include the button sound output (that is, the dual tone multi-frequency signal), the remote receiving terminal does not generate false positives and is erroneously controlled. The case of the application.

The video conference system and method disclosed in the above embodiments generate a corresponding string command according to the dual tone multi-frequency signal received by the telephone adapter, and then convert the string command into a keyboard button action according to a button conversion table to control The application facilitates video conferencing. Further, the video conferencing system and method of the present disclosure detects and eliminates the audio signals received from the network and the dual-tone multi-frequency signals in the audio signals to be transmitted to the network, thereby avoiding local and remote video recording. The conference system avoids situations in which an error control application is generated due to misjudgment of the DTMF signal.

In the above, the present invention has been disclosed in the above embodiments, but it is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100. . . Video conferencing system

110. . . Telephone

120. . . Telephone adapter

130. . . Network communication device

140. . . Network module

150. . . Audio module

162. . . Dual tone multi-frequency signal forwarding module

164. . . Keyboard event emitter

166. . . Dual tone multi-frequency cancellation module

168. . . Audio output module

169. . . Audio input module

TMP_LINKED_LIST. . . First buffer

Buffer. . . Second buffer

FIG. 1 is a block diagram of a video conferencing system in accordance with an embodiment.

2A and 2B are respectively a partial flow chart of a video conference method according to an embodiment.

FIG. 3 is a schematic diagram of a key conversion table according to an embodiment.

FIG. 4 is a schematic diagram of a first buffer and a second buffer of an audio input module according to an embodiment.

100. . . Video conferencing system

110. . . Telephone

120. . . Telephone adapter

130. . . Network communication device

140. . . Network module

150. . . Audio module

162. . . Dual tone multi-frequency signal forwarding module

164. . . Keyboard event emitter

166. . . Dual tone multi-frequency cancellation module

168. . . Audio output module

169. . . Audio input module

Claims (18)

A video conferencing system includes: a phone for generating a first dual tone multi-frequency signal; a telephone adapter connected to the phone for detecting the first dual tone multi-frequency signal and generating a a first command string; and a network communication device connected to the phone adapter and a network, and configured to convert the first command string into a first keyboard button action according to a button conversion table to control one An application, wherein the network communication device is further configured to receive a first audio signal via the network, and detect whether the first audio signal includes a second dual tone multi-frequency signal, if the first audio signal includes The second dual-tone multi-frequency signal is further configured to mute the portion of the first audio signal corresponding to the second dual-tone multi-frequency signal according to the detected result, and use the mute processing The first audio signal is output to the phone via the phone adapter. The video conferencing system of claim 1, wherein the network communication device comprises: a network module for establishing communication with the network; and an audio module comprising: a keyboard event transmitter The first command string is converted into the first keyboard button action according to the button conversion table; a dual tone multi-frequency signal forwarding module is configured to receive the first command string from the phone adapter and Forwarding the first command string to the keyboard event transmitter; an audio input module for receiving the first audio signal via the network, and detecting whether the first audio signal includes the second dual tone a frequency multi-frequency cancellation module for muting the portion of the first audio signal corresponding to the second dual-tone multi-frequency signal; and an audio output module for performing the mute processing The first audio signal is output to the phone via the phone adapter. The video conferencing system of claim 2, wherein the first audio signal comprises a plurality of first audio segments, the audio input module has a first buffer and a second buffer, the first buffer The device is configured to sequentially copy and temporarily store the first audio segments. When the data length of the first audio segments in the first buffer is greater than a maximum detection length, the first ones in the first buffer And the audio input module is combined with the displacement value to detect whether the first audio segments in the second buffer include the second dual tone. The multi-tone signal, if the first audio segment includes the second dual-tone multi-frequency signal, the dual-tone multi-frequency cancellation module sets the first audio segments in the second buffer to a value of zero. The video conferencing system of claim 3, wherein the audio input module further detects whether the first audio segments in the second buffer include the second dual tone multi-frequency signal, and repeatedly The number of detections is determined by one of the phone's pulse code modulation sampling frequency per second, the maximum detection length, and a delay range constant. The video conferencing system of claim 3, wherein the length of time of the first audio segments set to a value of 0 is determined by a delay basic unit, one of the phones, and a pulse code modulation sampling frequency per second. The maximum detection length is determined. The video conferencing system of claim 2, wherein the phone is further configured to generate a second audio signal, wherein the audio input module is further configured to detect whether the second audio signal includes a third dual tone a frequency signal, if the second audio signal includes the third dual tone multi-frequency signal, the dual tone multi-frequency cancellation module is further configured to correspond to the second audio signal according to the result detected by the audio input module The part of the three-tone multi-frequency signal is muted, and is used to output the second audio signal after the mute processing to the network via the network module. The video conferencing system of claim 6, wherein the second audio signal comprises a plurality of second audio segments, the audio input module having a first buffer and a second buffer, the first The buffer is configured to sequentially copy and temporarily store the second audio segments. When the data length of the second audio segments in the first buffer is greater than a maximum detection length, the first The second audio segment is combined in the second buffer to obtain a corresponding one of the displacement values, and the audio input module cooperates with the displacement value to detect whether the second audio segments in the second buffer include the third pair The multi-tone signal, if the second audio segment includes the third dual-tone multi-frequency signal, the dual-tone multi-frequency cancellation module sets the second audio segments in the second buffer to a value of zero. The video conferencing system of claim 7, wherein the audio input module further detects whether the second audio segments in the second buffer include the third dual tone multi-frequency signal, and repeatedly The number of detections is determined by one of the phone's pulse code modulation sampling frequency per second, the maximum detection length, and a delay range constant. The video conferencing system of claim 7, wherein the length of time of the second audio segments set to a value of 0 is determined by a delay basic unit, one of the phones, and a pulse code modulation sampling frequency per second. The maximum detection length is determined. A video conferencing method is applied to a video conferencing system, the video conferencing system includes a telephone, a telephone adapter, and a network communication device, the telephone adapter is connected to the telephone, and the network communication device is connected to the a telephone adapter and a network, the video conference method includes: generating a first dual tone multi-frequency signal by using the phone; detecting the first dual tone multi-frequency signal by using the telephone adapter, and generating a first a command string; the network communication device converts the first command string into a first keyboard button action according to a button conversion table to control an application; and the network communication device receives a first via the network An audio signal, and detecting whether the first audio signal includes a second dual tone multi-frequency signal; if the first audio signal includes the second dual tone multi-frequency signal, using the network communication device according to the detected result The part of the first audio signal corresponding to the second dual tone multi-frequency signal is muted, and the first audio signal after the mute processing is output to the phone via the telephone adapter. The video conferencing method of claim 10, wherein the network communication device comprises a network module and an audio module, wherein the network module is configured to establish communication with the network, the audio module The device includes a keyboard event transmitter, a dual-tone multi-frequency signal forwarding module, an audio input module, a dual-tone multi-frequency cancellation module, and an audio output module. The video conference method further includes: utilizing the dual tone The frequency forwarding module receives the first command string from the phone adapter and forwards the first command string to the keyboard event transmitter; using the keyboard event transmitter to use the key conversion table to the first command Converting the string to the first keyboard button action; receiving, by the audio input module, the first audio signal via the network, and detecting whether the first audio signal includes the second dual tone multi-frequency signal; The audio multi-frequency cancellation module mutes the portion of the first audio signal corresponding to the second dual-tone multi-frequency signal; and uses the audio output module to rotate the first audio signal after the mute processing via the telephone The output to the telephone. The video conferencing method of claim 11, wherein the first audio signal comprises a plurality of first audio segments, the audio input module has a first buffer and a second buffer, and the video conference method The method further includes: sequentially copying and temporarily storing the first audio segments by using the first buffer; and using the second when the data length of the first audio segments in the first buffer is greater than a maximum detection length The buffer combines the first audio segments in the first buffer and obtain a corresponding one of the displacement values; and the audio input module cooperates with the displacement value to detect whether the first audio segments in the second buffer are The second dual tone multi-frequency signal is included; and if the first audio segment includes the second dual tone multi-frequency signal, the first audio in the second buffer is used by the dual tone multi-frequency cancellation module The clip is set to a value of 0. The video conferencing method of claim 12, further comprising: detecting, by the audio input module, whether the first audio segments in the second buffer comprise the second dual tone multi-frequency signal, The number of times of repeated detection is determined by one pulse code modulation sampling frequency per second of the phone, the maximum detection length and a delay range constant. The video conferencing method of claim 12, wherein the length of time of the first audio segments set to a value of 0 is determined by a delay basic unit, one pulse per second of the telephone, and a sampling frequency of the pulse code. The maximum detection length is determined. The video conferencing method of claim 11, further comprising: generating a second audio signal by using the audio input module or the phone; and detecting, by the audio input module, whether the second audio signal includes a first a dual-tone multi-frequency signal; and if the second audio signal includes the third dual-tone multi-frequency signal, the dual-tone multi-frequency cancellation module is used to detect the second audio signal according to the result detected by the audio input module The part of the third dual-tone multi-frequency signal is muted, and the second audio signal after the mute processing is output to the network via the network module. The video conferencing method of claim 15, wherein the second audio signal comprises a plurality of second audio segments, the audio input module has a first buffer and a second buffer, and the video conference method The method further includes: sequentially copying and temporarily storing the second audio segments by using the first buffer; and using the second when the data length of the second audio segments in the first buffer is greater than a maximum detection length The buffer combines the second audio segments in the first buffer and obtain a corresponding one of the displacement values; and the audio input module cooperates with the displacement value to detect whether the second audio segments in the second buffer are The third dual tone multi-frequency signal is included; and if the second audio segment includes the third dual tone multi-frequency signal, the second audio in the second buffer is used by the dual tone multi-frequency cancellation module The clip is set to a value of 0. The video conferencing method of claim 16, wherein the audio input module further detects whether the second audio segments in the second buffer include the third dual tone multi-frequency signal, and repeatedly The number of detections is determined by one of the phone's pulse code modulation sampling frequency per second, the maximum detection length, and a delay range constant. The video conferencing method of claim 16, wherein the length of time of the second audio segments set to a value of 0 is determined by a delay basic unit, one of the telephones, and a pulse code modulation sampling frequency per second. The maximum detection length is determined.