CN101656596A - Media flow time delay detecting method and device - Google Patents
Media flow time delay detecting method and device Download PDFInfo
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Abstract
The invention discloses a media flow time delay detecting method and device, the method comprises: at an input point of a path to be detected, adding a predetermined characteristic code flow to a media code flow, and recording a current first time; at an output point of the path to be detected, detecting the output media code flow; when detecting the characteristic code flow, recording a current second time; calculating the difference of the second time and the first time to obtain time delay of the media flow of the path to be delayed. Through the method and device provided by the invention,the media code flow is performed processing and analysis on the signals, and the media flow time delay of the path to be delayed is obtained through calculating the time difference between addition ofcharacteristic code flow and detection thereof from the media code flow, compared with the prior method of macro estimation and code analysis section counter, the detection method is more objective,and the detection result is more accurate and reliable.
Description
Technical field
The present invention relates to the media stream signal process field, relate in particular to a kind of media flow time delay detecting method and device.
Background technology
In the transmission course of Media Stream, because of influences such as encoding and decoding time delay, propagation delay times, may cause both sides' sensory signal of communication not smooth, influence exchanges, be so-called labial stationary problem,, often need accurately to hold Media Stream critical path consuming time in order to avoid the nonsynchronous problem of labial occurring as far as possible, and accurately hold image code stream and the sound code stream time delay of flowing through in being equipped with critical path, thereby provide foundation accurately and reliably for the performance of improving stream media system.
Statistics and the detection of existing video/audio time of delay, mostly adopt the method that macroscopic view is estimated or code partial analysis segmentation is added up, but the elapsed time of each function is not corresponding one by one with the handled media data of function in the code, because the influence of buffering area in the program, the influence of interrupting, the influence of bus transfer, and the artificial subjective deviation of calculating etc. all may accumulate bigger wrong deviation, and adopt the method versatility of code partial analysis very poor, each code revision may all can exert an influence to media stream delay.
Summary of the invention
The embodiment of the invention provides a kind of media flow time delay detecting method and device, in order to Media Stream is realized time delay detection accurately and reliably.
A kind of media flow time delay detecting method that the embodiment of the invention provides comprises:
Input point in path to be measured adds default characteristic code flow, and writes down the current very first time in the medium code stream of input;
Output point in path to be measured detects the described media code stream of exporting; When detecting described characteristic code flow, the record current second time;
Calculate the poor of described second time and the described very first time, obtain the media flow time delay in described path to be measured.
The described characteristic code flow of presetting that adds in the medium code stream comprises:
One section of the input point in the path to be measured of the flowing through medium code stream with described default characteristic code flow equal in length is replaced to described characteristic code flow; Or
Among the medium code stream of the input point in the path to be measured of flowing through, insert default characteristic code flow.
The length of described characteristic code flow is consistent with the frame length of medium code stream;
Described media code stream to output detects, and comprising:
Medium code stream to output detects frame by frame, calculates the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow; Described degree of correlation value characterizes the degree of correlation between described medium code stream and the described characteristic code flow, and described degree of correlation value is the number between 0～1; Described degree of correlation value value is big more, and it is high more to characterize between described medium code stream and the described characteristic code flow degree of correlation;
The degree of correlation value that calculates is compared with default threshold value,, determine that a frame medium code stream of current detection is described characteristic code flow when described degree of correlation value during more than or equal to described threshold value.
Calculate the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow by following formula:
A＝<X，Y>/(|X|*|Y|)
In the following formula:
A is the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow;
X is the vector expression of described characteristic code flow;
Y is the vector expression of the medium code stream of each frame output;
＜X, Y〉be the inner product of vector X and vector Y;
| X| is the mould of vector X;
| Y| is the mould of vector Y.
The vector expression of described characteristic code flow is: X=100*cos (PI/4*N)+100*cos (PI/8*N) or X=100*cos (PI/8*N);
Wherein: PI=3.14159; N=0～239.
The media flow time delay detecting method that the embodiment of the invention provides also comprises: the media flow time delay that repeats the described path to be measured of repeated detection;
Testing result is repeatedly added up, obtain repeated detection result's average.
A kind of media flow time delay checkout gear that the embodiment of the invention provides comprises:
Adding device is used for the input point in path to be measured, adds default characteristic code flow in the medium code stream of input, and writes down the current very first time;
Detecting unit is used for the described media code stream of output is detected; When detecting described characteristic code flow, the record current second time;
Computing unit calculates the poor of described second time and the described very first time, obtains the media flow time delay in described path to be measured.
Described adding device also is used for one section of the input point in the path to be measured of the flowing through medium code stream with described default characteristic code flow equal in length is replaced to described characteristic code flow; Or
Among the medium code stream of the input point in the path to be measured of flowing through, insert default characteristic code flow.
Described detecting unit also is used for the medium code stream of output is detected frame by frame, calculates the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow; Described degree of correlation value characterizes the degree of correlation between described medium code stream and the described characteristic code flow; The length of described characteristic code flow is consistent with the frame length of medium code stream;
The degree of correlation value that calculates is compared with default threshold value,, determine that a frame medium code stream of current detection is described characteristic code flow when described degree of correlation value during more than or equal to described threshold value.
Described detecting unit also is used for calculating the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow by following formula:
A＝<X，Y>/(|X|*|Y|)
In the following formula:
A is the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow;
X is the vector expression of described characteristic code flow;
Y is the vector expression of the medium code stream of each frame output;
＜X, Y〉be the inner product of vector X and vector Y;
| X| is the mould of vector X;
| Y| is the mould of vector Y.
The beneficial effect of the embodiment of the invention is as follows:
A kind of media flow time delay detecting method and device that the embodiment of the invention provides, input point in path to be measured, in the medium code stream, add default characteristic code flow, write down the current very first time, output point in path to be measured, media code stream to output detects, when detecting characteristic code flow, write down the second current time, calculate the poor of second time and the very first time, media flow time delay as path to be measured, media flow time delay detecting method that the embodiment of the invention provides and device, media code stream is carried out Signal Processing and analysis, add characteristic code flow by calculating, and from the medium code stream, detect time difference between the characteristic code flow, obtain the media flow time delay in path to be measured, estimate to compare with the macroscopic view that prior art adopts with the method for code analysis segmentation statistics, detection method is comparatively objective, testing result is also more accurate and reliable, and, media flow time delay detecting method that the embodiment of the invention provides and device, can the media flow time delay on the difference path to be measured be detected, the time delay of individual equipment of for example can the medium code stream flowing through detects, also can detect the flow through overall delay of a plurality of equipment of medium code stream, detection method is all identical, and the method for the code partial analysis of adopting with prior art is compared, and has more versatility.
Description of drawings
The flow chart of the media flow time delay detecting method that Fig. 1 provides for the embodiment of the invention;
Signal flow moves towards figure in the example that Fig. 2 provides for the embodiment of the invention;
The particular flow sheet of the example that Fig. 3 provides for the embodiment of the invention;
The schematic diagram that adds the medium code stream after the characteristic code flow in the example that Fig. 4 provides for the embodiment of the invention;
The schematic diagram of detected characteristic code flow in the medium code stream that terminal equipment receives in the example that Fig. 5 provides for the embodiment of the invention;
The structural representation of the media flow time delay checkout gear that Fig. 6 provides for the embodiment of the invention.
Embodiment
Below in conjunction with accompanying drawing, use embodiment to be described in detail to a kind of media flow time delay detecting method provided by the invention and device.
The media flow time delay detecting method that the embodiment of the invention provides as shown in Figure 1, comprises the steps:
S101, in the input point in path to be measured, in the medium code stream of input, add default characteristic code flow, and write down the current very first time;
S102, at the output point in path to be measured, the media code stream of output is detected; When detecting characteristic code flow, the record current second time;
S103, calculate the poor of second time and the very first time, obtain the media flow time delay in path to be measured.
The above-mentioned flow process of utilizing the embodiment of the invention to provide, can the time delay of the processing procedure of some medium code stream keys be detected, for example detect audio code stream supplied with digital signal processor (Digital SignalProcessor, DSP) to the time delay between the output DSP, the perhaps time delay of other critical paths.Especially for complicated system, a plurality of separate equipment if the medium code stream is flowed through can detect the flow through time delay of individual equipment of medium code stream, perhaps the flow through time delay of a plurality of equipment of medium code stream are detected, and method of testing is identical.
In above-mentioned steps S101, in the medium code stream, add default characteristic code flow, can adopt one section medium code stream of the input point in the path to be measured of will flowing through to replace to the mode of default characteristic code flow with the characteristic code flow equal in length that should preset; Perhaps, the mode of this default characteristic code flow is inserted in employing among the medium code stream of the input point in the path to be measured of flowing through.
In above-mentioned steps S102, for the ease of detecting, the length of characteristic code flow can be selected consistent with the frame length of medium code stream, in the testing process, constantly the medium code stream to output detects frame by frame, every output one frame medium code stream just calculates once this frame medium code stream of current output and the degree of correlation value between the characteristic code flow; The degree of correlation value is high more, then shows between this frame medium code stream of current output and the characteristic code flow approximate more.
The medium code stream that calculates is compared with default threshold value with the degree of correlation value between the characteristic code flow,, just can determine that this frame medium code stream of current detection is exactly a characteristic code flow when the degree of correlation value that calculates during more than or equal to default threshold value.
Calculating the degree of correlation value calculates by adopting Normalized Cross Correlation Function.The expression formula of concrete function is: A=＜X, Y 〉/(| X|*|Y|), in the following formula:
A is the medium code stream of each frame output and the degree of correlation value between the characteristic code flow;
X is the vector expression of characteristic code flow;
Y is the vector expression of the medium code stream of each frame output;
＜X, Y〉be the inner product of vector X and vector Y;
| X| is the mould of vector X;
| Y| is the mould of vector Y.
Normalized Cross Correlation Function is to be used for describing two random vector signal X and the degree of correlation of Y between any two different t1 constantly and t2 value.If result of calculation A equals zero, the medium signal bit stream and the characteristic code flow signal of expression output are altogether irrelevant; If result of calculation A equals 1, the medium signal bit stream and the characteristic code flow signal of expression output are relevant fully.A levels off to 1 more, illustrates that the similitude of two signals is high more.Normalized Cross Correlation Function has provided two judge index whether signal is correlated with in frequency domain.
If current output code flow is very high with the degree of correlation of characteristic code flow, can choose a threshold value according to actual conditions, such as 0.95,, can determine that then this frame medium code stream of current output is exactly a characteristic code flow when the degree of correlation value A that calculates surpasses 0.95.
For the media flow time delay detecting method that illustrates that better the embodiment of the invention provides,, lift a concrete example explanation at this.
In this example, the practical application scene of the time delay detection of handling with the TV conference system sound intermediate frequency is that example is introduced, but the media flow time delay detecting method that the embodiment of the invention provides does not limit to the testing process of the time delay of audio frequency, is equally applicable to for example detection of video, image etc. of other Media Streams.
Fig. 2 be in this example signal flow move towards figure, in this example, need to detect be the medium code stream behind terminal equipment, arrive local side apparatus MCU, flow out the overall delay in incoming terminal this section of equipment path to be measured, back then again from local side apparatus MCU.
Before detecting beginning, the linear audio code stream of selecting to generate behind the terminal equipment sound intermediate frequency data sampling (i.e. the medium code stream of the input point in this path to be measured input) inserts characteristic code flow, the linear media code stream is sent to local side apparatus MCU after encoding, and then be back to terminal equipment, when detecting, select the linear media stream of preparing after the decoding in the terminal equipment to play (i.e. the medium code stream of the output point in this path to be measured output) is detected.
Idiographic flow below in conjunction with media flow time delay in this example under accompanying drawing 3 explanations detects comprises the steps:
Add characteristic code flow in S301, the linear media code stream that behind terminal equipment sound intermediate frequency data sampling, generates, and record current time T1.
Shown in Figure 4 is one section schematic diagram that adds characteristic code flow medium (audio frequency) code stream afterwards.Shown in the square frame among Fig. 4 is the characteristic code flow that adds.
Choosing of characteristic code flow preferably, selected and the conventional bigger code stream of medium code stream difference, in addition, for the convenience that detects, can select the length of characteristic code flow to equal the frame length of medium code stream.
The vector expression of a typical characteristic code flow is: X=100*cos (PI/4*N)+100*cos (PI/8*N), wherein, PI=3.14159, N=0～239, characteristic code flow has been chosen 240 points altogether, has been equivalent to prepare the media data of 30ms for the voice of sample rate 8K.
Two kinds of cosine component 100*cos (PI/4*N) and 100*cos (PI/8*N) have been chosen in the vector expression of characteristic code flow, purpose is to make characteristic code flow more special, with difference and conventional medium code stream, and can increase the noiseproof feature of characteristic code flow, in addition, these two cosine components calculate during convenient the test at 240 interior quadratures.
Perhaps in order further to simplify computing, for example can also select the following characteristics code stream, this characteristic code flow is single cosine signal, vector expression is: X=100*cos (PI/8*N), wherein, PI=3.14159, N=0～239, this characteristic code flow have been chosen 240 points altogether.
S302, the decoded linear media stream that returns at terminal equipment reception local side apparatus MCU detect frame by frame.
In this step S302, when whenever receiving the medium code stream of a frame (240 point), just detect once, be a frame that receives that the medium code stream of 240 points is represented with Y, calculate according to the following equation with characteristic code flow X then: A=＜X, Y/(| X|*|Y|).
Computational process is as follows:＜X, Y 〉=x (0) * y (0)+x (1) * y (1)+...+x (239) * y (239);
|X|＝sqrt(x(0)*x(0)+x(1)*x(1)...+x(239)*x(239))；
|Y|＝sqrt(y(0)*y(0)+y(1)*y(1)...+y(239)*y(239))。
Function sqrt represents to ask arithmetic root in the aforementioned calculation process, because the value of A approaches 1 more, this frame medium code stream that then shows characteristic code flow and current detection is approximate more, with A=＜X, Y 〉/(| the result who X|*|Y|) calculates, for example 0.9 compare with preset threshold, if the value of A is more than or equal to 0.9 then think that this frame code stream of current detection is the characteristic code flow of previous adding.
S303, when detecting characteristic code flow, write down current time T 2.
Fig. 5 is the schematic diagram of detected characteristic code flow in the medium code stream that receives of terminal equipment, and what illustrate in the square frame is detected characteristic code flow.
S304, the time difference of calculating T2 and T1 have promptly obtained the medium code stream behind terminal equipment, arrive local side apparatus MCU, flow out the overall delay in incoming terminal this section of equipment path to be measured, back then again from local side apparatus MCU.
In order to improve the accuracy of media flow time delay further, in this example, can also repeatedly repeat above-mentioned steps S301 to step S304, need between repeating to guarantee to have time enough at interval at every turn.Each repeated execution of steps S301 is added up to the testing result that step S304 obtains, calculate repeated detection result's average, as the final detection result of this path to be measured media flow time delay.
Be that example describes with the audio code stream in this example, for video flowing, can sample to certain delegation's pixel of the every two field picture of video flowing and form linear medium code stream, in the medium code stream that forms, add characteristic code flow then, the method that detects is consistent with above-mentioned steps S301 to S304, does not repeat them here.
Based on same inventive concept, a kind of media flow time delay checkout gear also is provided in the embodiment of the invention, because this device is realized based on aforementioned media flow time delay detecting method, the principle of being dealt with problems is similar to the operation principle of aforementioned a kind of media flow time delay detecting method, therefore the concrete enforcement of this device can repeat part and not give unnecessary details referring to the enforcement of method.
A kind of media flow time delay checkout gear that the embodiment of the invention provides as shown in Figure 6, comprising:
Adding device 601 is used for the input point in path to be measured, adds default characteristic code flow in the medium code stream of input, and writes down the current very first time;
Detecting unit 602 is used for the media code stream of output is detected; When detecting characteristic code flow, the record current second time;
Computing unit 603 calculates the poor of second time and the very first time, obtains the media flow time delay in path to be measured.
Adding device 601 also is used for one section of the input point in the path to be measured of the flowing through medium code stream with default characteristic code flow equal in length is replaced to characteristic code flow; Or
Among the medium code stream of the input point in the path to be measured of flowing through, insert default characteristic code flow.
Detecting unit 602 also is used for the medium code stream of output is detected frame by frame, calculates the medium code stream of each frame output and the degree of correlation value between the characteristic code flow; Degree of correlation between degree of correlation value characterizing media code stream and the characteristic code flow; The length of characteristic code flow is consistent with the frame length of medium code stream;
The degree of correlation value that calculates is compared with default threshold value,, determine that a frame medium code stream of current detection is described characteristic code flow when degree of correlation value during more than or equal to threshold value.
Detecting unit 602 also is used for calculating the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow by following formula:
A＝<X，Y>/(|X|*|Y|)
In the following formula:
A is the medium code stream of each frame output and the degree of correlation value between the characteristic code flow;
X is the vector expression of described characteristic code flow;
Y is the vector expression of the medium code stream of each frame output;
＜X, Y〉be the inner product of vector X and vector Y;
| X| is the mould of vector X;
| Y| is the mould of vector Y.
A kind of media flow time delay detecting method and device that the embodiment of the invention provides, input point in path to be measured, in the medium code stream of input, add default characteristic code flow, write down the current very first time, output point in path to be measured, media code stream to output detects, when detecting characteristic code flow, write down the second current time, calculate the poor of second time and the very first time, media flow time delay as path to be measured, media flow time delay detecting method that the embodiment of the invention provides and device, media code stream is carried out Signal Processing and analysis, by calculate to add characteristic code flow and from the medium code stream, detect time difference between the characteristic code flow, obtain the media flow time delay in path to be measured, estimate to compare with the macroscopic view that prior art adopts with the method for code analysis segmentation statistics, detection method is more objective, testing result is also more accurate and reliable, and, media flow time delay detecting method that the embodiment of the invention provides and device, can the media flow time delay on the different paths to be measured be detected, the time delay of individual equipment of for example can the medium code stream flowing through detects, also can detect the flow through overall delay of a plurality of equipment of medium code stream, detection method is all identical, the method of the code partial analysis of adopting with prior art is compared, and has more versatility.
In addition, in media flow time delay detecting method that the embodiment of the invention provides and the device, characteristic code flow adopts the code stream that differs greatly with conventional medium code stream, has strengthened the anti-interference of characteristic code flow, has improved the accuracy and the reliability of testing result.
Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.
Claims (10)
1, a kind of media flow time delay detecting method is characterized in that, comprising:
Input point in path to be measured adds default characteristic code flow, and writes down the current very first time in the medium code stream of input;
Output point in path to be measured detects the described media code stream of exporting; When detecting described characteristic code flow, the record current second time;
Calculate the poor of described second time and the described very first time, obtain the media flow time delay in described path to be measured.
2, the method for claim 1 is characterized in that, the described characteristic code flow of presetting that adds in the medium code stream comprises:
One section of the input point in the path to be measured of the flowing through medium code stream with described default characteristic code flow equal in length is replaced to described characteristic code flow; Or
Among the medium code stream of the input point in the path to be measured of flowing through, insert default characteristic code flow.
3, method as claimed in claim 2 is characterized in that, the length of described characteristic code flow is consistent with the frame length of medium code stream;
Described media code stream to output detects, and comprising:
Medium code stream to output detects frame by frame, calculates the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow; Described degree of correlation value characterizes the degree of correlation between described medium code stream and the described characteristic code flow, and described degree of correlation value is the number between 0～1; And described degree of correlation value is big more, and it is high more to characterize between described medium code stream and the described characteristic code flow degree of correlation;
The degree of correlation value that calculates is compared with default threshold value,, determine that a frame medium code stream of current detection is described characteristic code flow when described degree of correlation value during more than or equal to described threshold value.
4, method as claimed in claim 3 is characterized in that, calculates the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow by following formula:
A＝<X，Y>/(|X|*|Y|)
In the following formula:
A is the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow;
X is the vector expression of described characteristic code flow;
Y is the vector expression of the medium code stream of each frame output;
＜X, Y〉be the inner product of vector X and vector Y;
| X| is the mould of vector X;
| Y| is the mould of vector Y.
5, method as claimed in claim 4 is characterized in that, the vector expression of described characteristic code flow is: X=100*cos (PI/4*N)+100*cos (PI/8*N) or X=100*cos (PI/8*N);
Wherein: PI=3.14159; N=0～239.
6, as the described method of the arbitrary claim of claim 1-5, it is characterized in that, also comprise: the media flow time delay that repeats the described path to be measured of repeated detection;
Testing result is repeatedly added up, obtain repeated detection result's average.
7, a kind of media flow time delay checkout gear is characterized in that, comprising:
Adding device is used for the input point in path to be measured, adds default characteristic code flow in the medium code stream of input, and writes down the current very first time;
Detecting unit is used for the described media code stream of output is detected; When detecting described characteristic code flow, the record current second time;
Computing unit calculates the poor of described second time and the described very first time, obtains the media flow time delay in described path to be measured.
8, device as claimed in claim 7 is characterized in that, described adding device also is used for one section of the input point in the path to be measured of the flowing through medium code stream with described default characteristic code flow equal in length is replaced to described characteristic code flow; Or
Among the medium code stream of the input point in the path to be measured of flowing through, insert default characteristic code flow.
9, device as claimed in claim 8 is characterized in that, described detecting unit also is used for the medium code stream of output is detected frame by frame, calculates the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow; Described degree of correlation value characterizes the degree of correlation between described medium code stream and the described characteristic code flow; The length of described characteristic code flow is consistent with the frame length of medium code stream;
The degree of correlation value that calculates is compared with default threshold value,, determine that a frame medium code stream of current detection is described characteristic code flow when described degree of correlation value during more than or equal to described threshold value.
10, device as claimed in claim 9 is characterized in that, described detecting unit also is used for calculating the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow by following formula:
A＝<X，Y>/(|X|*|Y|)
In the following formula:
A is the medium code stream of each frame output and the degree of correlation value between the described characteristic code flow;
X is the vector expression of described characteristic code flow;
Y is the vector expression of the medium code stream of each frame output;
＜X, Y〉be the inner product of vector X and vector Y;
| X| is the mould of vector X;
| Y| is the mould of vector Y.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102158334A (en) * | 2011-01-28 | 2011-08-17 | 北京视博云科技有限公司 | Internet protocol quadrature amplitude modulation (IPQAM) equipment delay detection method and device |
| CN102158726A (en) * | 2011-01-28 | 2011-08-17 | 北京视博云科技有限公司 | Time delay detection method and device of encoder |
| CN102169664A (en) * | 2011-01-28 | 2011-08-31 | 北京视博云科技有限公司 | Time delay detecting method and device of display device |
| CN102740411A (en) * | 2012-06-08 | 2012-10-17 | 张巍 | Wireless microphone system based on WIFI (wireless fidelity) wireless network |
| CN107231266A (en) * | 2016-03-24 | 2017-10-03 | 中兴通讯股份有限公司 | The detection method and device of message passage |
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2009
- 2009-09-17 CN CN200910169497A patent/CN101656596A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102158334A (en) * | 2011-01-28 | 2011-08-17 | 北京视博云科技有限公司 | Internet protocol quadrature amplitude modulation (IPQAM) equipment delay detection method and device |
| CN102158726A (en) * | 2011-01-28 | 2011-08-17 | 北京视博云科技有限公司 | Time delay detection method and device of encoder |
| CN102169664A (en) * | 2011-01-28 | 2011-08-31 | 北京视博云科技有限公司 | Time delay detecting method and device of display device |
| CN102169664B (en) * | 2011-01-28 | 2013-08-21 | 北京视博云科技有限公司 | Time delay detecting method and device of display device |
| CN102158334B (en) * | 2011-01-28 | 2014-04-23 | 北京视博云科技有限公司 | Internet protocol quadrature amplitude modulation (IPQAM) equipment delay detection method and device |
| CN102740411A (en) * | 2012-06-08 | 2012-10-17 | 张巍 | Wireless microphone system based on WIFI (wireless fidelity) wireless network |
| CN107231266A (en) * | 2016-03-24 | 2017-10-03 | 中兴通讯股份有限公司 | The detection method and device of message passage |
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