AVS (audio video standard) audio and video presynchronizing method based on RTP (real time protocol) package

The technical field of

[0001] the invention claims a stream media synchronous field especially relates to rtp package avs transmission of audio video frequency media to the field of synchronous.

Background technology

Is avs [ 0002 audio video coding standard audio video frequency coding standard of digital audio/video encoding/decoding technical standard of the working group the digital audio and video frequency coding standard. Avs standard comprises a system video frequency audio frequency digital rights management mobile video and 9 parts. Avs multi-media communication system multiple when it does not ensure the qos quality of service quality of service grouping exchanging network to carry out real-time multimedia data transmission of the user is desired it has good quality of service ensuring the network and the reliability and transmission time delay and so on real time data communication in the process is usually met by such as packet loss random sequence jitter repeatedly and a series problem. In order to in network and effectively transmit the real-time data ietf internet internet engineering task force engineering tasks and development of the real timetransport rtp protocol real-time transmission protocol. Is rtp interactive audio frequency video and has real time property of the data providing end to end the transmission service it comprises two relation of intimate protocol rtp and rtcp real which transport controlprotocol real time transmission control protocol.

[0003] is rtp is used for internet to the multimedia data flow the invention claims a transmission protocol rtp main body and it is not only can be orderly transmitting data packet and providing reliable transmitting mechanism and it does not provide flow control and congestion control comprising the invention claims an rtcp and these services. Rtp and rtcp to provide flow control and congestion control service. Server using rtcp information dynamically changes the transmission speed is even it can change the effective load type. Rtp and rtcp used by matching with each other and they can effectively the feedback and the minimum expense of the transmission efficiency of optimization so it is especially suitable for transmission network of the real time data.

[0004] for solving the problem of avs video frequency in the network transmission time delay dithering generated by the synchronization problem generally adopts the method comprises the steps of receiving terminal adding the jitter buffer area. No matter what of the added is rtp packet receiving buffer area of decoding buffer and image display buffer area is also near the invention claims a double buffering region although it can be on a certain degree reducing the delay jitter of the first majority * periodically by changing the buffer size media to eliminate in time delay jitter and then the image display buffer area according to audio and video playback time whether or not the same performing frame-lost or repeatedly displaying *** frame image and the actual synchronizing effect is not ideal at all. The invention claims a more effective method to it solves the problem that the time delay dithering generated by the synchronization problem is not only depends on adjusting the size of the buffer area to realize the synchronous media playback. The method is rtp packet before it is carried out once a synchronization so as to ensure the whole of the audio the video *.

The content of invention

[0005] this invention claims a based on rtp package of avs video frequency synchronization method of preventing. Which is used for the avs system body to carry out audio video frequency synchronization before the first early * at the same time through establishing rtp audio video frequency package based on absolute playback time interval mapping rapidly determine the audio video frequency media and media in the desynchronizing condition and make relevant adjustment so as to reach the audio video frequency synchronization effect.

[0006] the purpose of this invention lies in the rtp package sent by the avs video at the same *. So this invention aims at the avs system and rtp and rtcp packet the characteristic of the avs system to the audio and video executing the exact synchronous front it makes full use of rtp packet head field the time stamp data type frame number and rtcp packet head of the time stamp information to the audio video frequency for the first preset at the same time and guarantee to achieve the main body of the audio video frequency synchronization effect.

[0007] needed specification of the avs audio and video the invention is rtp package and sending corresponding to the ground are respectively installed to rtp audio frequency package and video frequency package rtp message and it is not specifically refers to which they are inches the invention is rtp audio video frequency package or rtp package. Received rtp audio frequency package buffer zone of called audio buffer region that receives video frequency package rtp buffer zone of called video buffer area the body which does not have point the invention claims a buffer area when they are formed said audio-video buffer area buffer area or. Audio buffer area of the rtp audio frequency package is to a certain *** one rtp video frequency package formed by the called mapping module mapping module audio video buffer area of the rtp video frequency package is to a certain *** one rtp audio frequency package formed by the mapping module called video frequency mapping file block is not specifically the invention claims a mapping module which is easy to *** said system the mapping module. Also need to get the mapping module it is composed of *** one or more than one rtp packet and a lack mark if sequence number mapping block is not lost it is not be lost serial number mark is composed of. File to be processed the audio frequency media and video frequency media when there is not specifically the media system which is used for representing *** media. Sr packet is *** utility model claims an rtcp packet. The invention requires to rtp packet the packet head field expanding one byte is used to mark the rtp pack number of frames of video frame the frame head frame amount representing. If it is especially the file in the symbol of unit is millisecond.

[0008] based on rtp package of the avs video frequency synchronization method comprising the following steps:

Following steps of i receiving rtp audio video frequency package:

Starting received rtp audio video frequency package thread of the audio buffer area is the initial value to am; Opening video buffer area is the initial value as vm preparing to receive new by rtp audio frequency package and video frequency package rtp;

Step 2 analyzes the package delay to the property and processing:

Starting analyzing rtp packet head field information of the thread analyzing the rtp audio frequency package or rtp video frequency package sequence number of the rtp package sequence number of the towel zhen listener *** in a table of the sequence number from small to big according to the sequence one by one compared with the sequence number and the surface of the sequence number is different and less than the minimum values in the invention is that the late and can realize synchronization of the package bag to directly throw away it does not enter into the buffer area queue; If the sequence number and the surface of the sequence number is different which is larger than surface of the minimum then it proves that the packet is not to delay the packet the packet going into buffer area analyzing the head field information preparing form a new mapping block; If and the surface in sequence numbers are identical then it proves that the delay is the only can be also can realize synchronization of the rtp package to enter buffer zone preparing fast determination in the queue in a position;

To the late but also can realize synchronization of rtp packet firstly finding a missing sequence number of the mark of mapping block then transferring the packet sequence number and the mapping module lacking mark the sequence number and comparing if it is the same then it proves that the packet belonging to the mapping module which is fixed position; If it is different and the lower *** plurality of containing losing sequence number of the mark of mapping block lack mark the sequence number comparing the determining the position;

Step 3 calculating absolute playback time interval:

Analyzing the rtp audio frequency package or rtp video frequency package of the rtp time stamp and obtaining the sender report sr a sender report package of the rtp time stamp and network protocol ntp which network time protocol time stamp calculating the rtp packet represented by the absolute playback start time;

Analyzing rtp audio frequency package or rtp video frequency package the portable * data type of the audio or video frame if it is audio frequency frame the rtp packet is complete the whole audio frequency frame analyzing out its frame number; If it is video frame the rtp package is not to be a whole and the video frame analyzing out the frame head amount; And according to the using interpolation method obtain the corresponding to the absolute playback time interval length;

According to step and calculating the rtp audio frequency package or rtp video packet represented by the absolute playback time interval ] [ x y and x is a absolute playback start time of the y is a absolute playback ending time;

Step 4 building rtp audio video frequency package mapping: Starting mapping thread because of the audio and video at the same axle is absolute time playback the absolute time axis as the bridge is established the rtp pack a plurality of media *** the relative mapping of media at the same time the rtp package to form a new mapping block or adding *** of the existed the mapping module is established mapping rtp package;

Step 5 judging desynchronizing condition media:

Start and judge synchronous lines of the program according to the established is rtp audio frequency package and video frequency package rtp related to absolute playback time of the mapping begin to detect rtp audio frequency package and video frequency package of the rtp desynchronizing condition and to make the corresponding to the adjustment of synchronous situation analysis and losing step is divided into three situations: First condition is that its middle *** media corresponding to the media *** the integrity chi rtp package to the second condition is in a certain media appears in the individual rtp package to delay the third condition is the first and second at the same time the invention claims a method for situation *;

Step 6 process is not synchronizing/ desynchronizing condition:

To the first synchronous signal between media in * and desynchronizing treatment it comprises the steps as follows: It does not delay of the media and the whole body of the delay time t and the rtp package; At the same inches the media buffer area can still receive new from the rtp package to the new of the rtp package to said step 2 is on the judgement processed it only needs to the packet is not to delay and it is not the same step of rtp package to the memory to start to submit request to zeng said buffer capacity to contain more rtp package; The integrity is rtp package to the delay of media then at time t in the waiting time of the rtp package to the cluster -inch at the same to the sending terminal sends feedback information notification sending terminal reduces the media packet frequency;

To the second synchronous condition the media desynchronizing treatment it comprises the steps as follows: The media buffering area in the rtp package does not take the whole time delay processing and it does not to the terminal sends feedback information the interception end *** to intercepts the dan delay but also can realize synchronization of the immediately according to step 2 in the method for processing media in the rapid synchronization;

The third mixed * or the mixture is * firstly does not delay of media to the delay time t and the rtp package; At the same inches the media buffer area can still receive new from the rtp package to the new of the rtp package to said step 2 is on the judgement processed it only needs to the packet is not to delay and it is not the same step of rtp package to the memory to start to submit request to zeng said buffer capacity to contain more rtp package; The integrity is rtp package to the delay of media then at time t in the waiting time of the rtp package group from the sending terminal sends feedback information notification sending terminal reduces the media packet frequency; And at the same time the detecting end *** once intercepts the individual to delay but also can realize synchronization of the immediately according to step 2 in said method to process media is fast and *.

[0009] as the invention is *** improvement step 3 in the calculated in the rtp package to the set starting time to formula is as follows b = ts ts /k and 1000 to the ts is sr for the 64 digits ntp time stamp is sr ts packet in the 32 is rtp time stamp is rtp package to said 32 bits time stamp k is audio or video frame of the sampling frequency.

[0010] as the invention is *** improvement step 3 in the middle of the interpolation method is to the audio frequency known frame the sampling frequency of the k and frame number m uses formula ta m = /k and the interval length of the ta is insulating to the audio frequency the time interval length according to the video if the rtp package and package the whole video frame is calculated according to the audio frequency frame of the method calculating the tv program is the video playback absolute time interval length; Package if only one of the video frames or macro block strip it does not comprise frame head the time interval tv = o; At the same time if there is packaging the video frame head the head of each frame is represented as *** whole of the video frame time the calculation program with and calculating audio frequency frame of the formula is the same frame number m it is video data frame head k is still of the video frame the sampling rate.

[0011] as the invention is *** improvement step 3 in the calculated in rtp audio frequency package absolute playback ending time of the method uses formula to tae = and the ta tae representing the rtp audio frequency package the absolute playback ending time b represents the rtp audio frequency package the absolute playback start time ta representing the rtp audio frequency package the absolute playback time interval length.

[0012] as the invention is *** improvement of the computer rtp video frequency package absolute playback ending time of the method uses formula tve = to the tv in the rtp tve indicating the video frequency package the absolute playback ending time b represents the rtp video frequency package the absolute playback start time is rtp tv indicating the video frequency package the absolute playback time interval length; The rtp audio frequency package will be put the absolute time interval between ta tae on rtp video frequency package will be put the absolute time interval tv tve ] [.

[0013] as the invention is *** improvement of the waiting time t by the following two states determined: If there is the delay of media constantly receives new to rtp packet and the time ti to reach the buffer area of the upper limit for the integrity of rtp package to the delay of media it does not finish the media block mapping at the same time the time t = tl; If there is the delay of media body does not reach the buffer area the upper limit h when the integrity of rtp package to the delay of media in the time t2 has been completed media block mapping at the same time the time t = t2; Media block mapping at the same * is entering the buffer area of each rtp packets can be found relative to the other end of the media mapping but it does not ensure that each mapping each piece is rtp package there is no loss of.

[0014] as the invention is *** improvement in the buffer area it mainly comprises frame monitoring terminal and mapping block two modules the two modules are cooperated working mechanism of the following: *** end of frame monitoring module it mainly comprises *** zhang chi to but also can realize synchronization of rtp package of packet sequence number of the surface of the sequence number in the table from small to big according to the order of storing; When receiving *** new of the rtp package to the package the sequence number and the surface of the sequence number from small to big according to the sequence one by one compared with the sequence number and the surface of the sequence number is different and less than the minimum values in the invention is that the late and can realize synchronization of the package bag to directly throw away it does not enter into the buffer area queue; If the sequence number and the surface of the sequence number is different which is larger than surface of the minimum then it proves that the packet is not to delay the packet the packet going into buffer area analyzing the head field information preparing form a new mapping block; If the serial number and list of some sequence number is the same then it proves that the delay is the only can be also can realize synchronization of the rtp package to the buffer area.

[0015] as the invention is *** improvement to the delay but also can realize synchronous rapidly determine rtp package in the queue in the position of the method is as follows: Firstly finding a missing sequence number of the mark of mapping block then transferring the packet sequence number and the mapping module lacking mark the sequence number and comparing if it is the same then it proves that the packet belonging to the mapping module which is fixed position; If it is different is connected with the upper and lower two *** comprising losing sequence number of the mark of mapping block lack mark the sequence number comparing the determining the position.

[0016] as the invention is *** improves the surface of the two states in real time update: The first one is that when forming *** new mapping block the mapping module is detecting whether or not block or in adjacent block is set between the lacking of rtp packet sequence number at the same time checking whether the neighbouring mapping module which has been make losing sequence number mark; If there is the sequence number is added to the deletion serial number mark in the same time the sequence number transmitted to the interception *** end of the module to update list the list zeng the one of the lost packet sequence number; If there is not be lost serial number mark and it does not to the interception *** end of the surface of the module transmits the sequence number loss; *** is when the mapping module to carry out the rtp package inches and the mapping module still has shortage of the serial number mark the deficiency of mark the sequence number transmitted to the interception *** end of the surface of the middle to update the deleting list and the losing sequence number of the same sequence number.

[0017] this invention has the beneficial effects of this utility model is that: Rtp audio video frequency package after the first synchronization processing is eliminated after the in the network transmission media is generated by the shake and media between the time delay difference. Message exchange between the rtp package to the audio video frequency media has finished the initial * the synchronization of this utility model can ensure the subsequent the avs system to the audio frequency decoding then accurate and synchronous playback.

[0018] the method of the invention is the most obvious feature is rtp it fully makes use of the audio video frequency package the head field portable * the time stamp information and the transmitting terminal executes the rtp package the mark the rtp package head field the data type frame amount information and so on the first do once it is complete effective synchronous processing it ensures the follow-up of the avs system to carry out precise audio video frequency synchronization playing back. The method can be the medium in the synchronous media the desynchronizing and mixed synchronous to effectively adjust so as to reach the avs video main body of the synchronous effect at the same time because it adopts dynamic application buffer area the method avoids the memory in the waste of resource.

Specification attached drawing

[0019] i receiving an rtp audio video frequency package the audio video buffer structure image display;

Picture 2 the first rtp video frequency package setting up relating to time of map it is not;

Picture 3 rtp audio video frequency package the media is as diagram;

Picture 4 rtp audio video frequency package the synchronous media the image display; 5 rtp an audio video frequency package the mixed synchronous diagram;

Picture 6 rtp audio video frequency package effectively at the same time of the image display;

Picture 7 rtp audio video frequency package the synchronous process of image display.

Specific implementing manner

[0020] a lower surface of the attached drawing specification and a specific embodiment of this invention the invention further ***.

[0021] practical implement method is as follows:

I receiving rtp audio video frequency package:

Starting received rtp audio video frequency package thread of the audio buffer area is the initial value to am; Opening video buffer area is the initial value as vm preparing to receive new by rtp audio frequency package and video frequency package rtp. Image in the i a1 a2

Is rtp an audio frequency package sequence number of vm vi v2 is rtp video frequency package sequence number of said represented by the real sequence number and is not necessarily is continuous. The outside of i image in other image does not have picture output audio frequency *** end of video interception interception port and deficiency of mark of the actual is the only is used for subsequent clearly the invention is not drawn out to.

[0022] 2 analyzes the package delay to the property and processing:

Starting analyzing the rtp packet head field information of the thread analyzing the rtp audio frequency package or rtp video frequency package sequence number of the rtp package sequence number of the towel zhen listener *** in a table of the sequence number from small to big according to the sequence by a comparison. If the sequence number and the surface of the sequence number is different and less than the minimum values in the invention is that the late and can realize synchronization of the package bag to directly throw away it does not enter into the buffer area queue; If the sequence number and the surface of the sequence number is different which is larger than surface of the smallest common than the maximum of the invention is the packet is not to delay the packet the packet going into buffer area analyzing the head field information preparing form a new mapping block; If and the surface in sequence numbers are identical then it proves that the delay is the only can be also can realize synchronization of the rtp package to enter buffer zone preparing fast determination in the queue in a position. The audio and video buffer area the structure is as picture i show.

[0023] to the late but also can realize synchronization of rtp packet firstly finding a missing sequence number of the mark of mapping block then transferring the packet sequence number and the mapping module lacking mark the sequence number and comparing if it is the same then it proves that the packet belonging to the mapping module which is fixed position; If it is different and the lower *** plurality of containing losing sequence number of the mark of mapping block lack mark the sequence number comparing the determining the position. So as to realize the audio medium in the fast at the same *.

[0024] calculating absolute playback time interval:

Continuous parsing thread and starting the computer thread.

[0025] analyzing the rtp audio frequency package or rtp video frequency package of the rtp time stamp and obtaining any one of sr the rtp time stamp and ntp time stamp. Calculating the rtp packet represented by the absolute playback start time of the calculated in the rtp package to the set starting time to formula is as follows b = ts ts /k and 1000 to the ts is sr for the 64 digits ntp time stamp is sr ts packet in the 32 is rtp time stamp is rtp package to said 32 bits time stamp k is audio or video frame of the sampling frequency.

[0026] analyzing rtp audio frequency package or rtp video frequency package the portable * data type of the audio or video frame if it is audio frequency frame the rtp packet is complete the whole audio frequency frame analyzing out its frame number; If it is video frame the rtp package is not to be a whole and the video frame analyzing out the frame head amount; And according to the using interpolation method obtain the corresponding to the absolute playback time interval length; And according to the using interpolation method obtain the corresponding to the absolute playback time interval length of the interpolation method is to the audio frequency known frame the sampling frequency of the k and frame number m uses formula ta m = /k and the interval length of the ta is insulating to the audio frequency the time interval length. To the video if the rtp package and package the whole video frame is calculated according to the audio frequency frame of the method calculating the tv program is the video playback absolute time interval length; Package if only one of the video frames or macro block strip it does not comprise frame head the time interval tv = o; At the same time if there is packaging the video frame head the head of each frame is represented as *** whole of the video frame time the calculation program with and calculating audio frequency frame of the formula is the same frame number m it is video data frame head k is still of the video frame the sampling rate.

[0027] according to step and calculating the rtp audio frequency package or rtp video packet represented by the absolute playback time interval ] [ x y and x is a absolute playback start time of the y is a absolute playback ending time.

[0028] calculating rtp audio frequency package absolute playback ending time of the method uses formula to tae = and the ta tae representing the rtp audio frequency package the absolute playback ending time b represents the rtp audio frequency package the absolute playback start time ta representing the rtp audio frequency package the absolute playback time interval length.

[0029] calculating rtp video frequency package absolute playback ending time of the method uses formula tve = to the tv in the rtp tve indicating the video frequency package the absolute playback ending time b represents the rtp video frequency package the absolute playback start time is rtp tv indicating the video frequency package the absolute playback time interval length. With rtp audio frequency package is set as an example *** audio frequency package with 150 audio frequency frame rate 8k the sampling interval time l per 8ms we can use calculating the interval length 18 75ms. Is set on the whole frame of the rtp video frequency package is same to the processing is equipped with strip belt or macro blocks and they are through judging the rtp is set on the frame head to amount of calculation interval length.

[0030] rtp according to the audio frequency package will be put the absolute time interval between ta tae on rtp video frequency package will be put the absolute time interval tv tve ] [.

[0031] 4 building rtp audio video frequency package mapping:

Starting mapping thread because of the audio and video at the same axle is absolute time playback the absolute time axis as the bridge is established the rtp pack a plurality of media *** the relative mapping of media at the same time the rtp package to form a new mapping block or adding *** of the existed the mapping module rtp packet established mapping and forming mapping is shown as picture 2 1.

[0032] 5 judging desynchronizing condition media:

Start and judge synchronous lines of the program according to the established is rtp audio frequency package and video frequency package rtp related to absolute playback time of the mapping begin to detect rtp audio frequency package and video frequency package of the rtp desynchronizing condition and to make the corresponding to the adjustment of synchronous situation analysis and losing step is divided into three situations first condition is that its middle *** media corresponding to the media *** is rtp package integrity chi rtp package to the called number of rtp package such as media the continuous three or more than one rtp packet sequence number loss we can be judged as the first condition is as follow the picture 3 represented; The second condition is in a certain media appears in the rtp pack delay for each such as media the continuous two and the lower part of the rtp pack delay the time they can be used to judge that the first and second condition in step 4 the display picture; The third condition is the first and second at the same time the condition such as media at the same time the continuous three and is rtp package to the delaying and continuous two and is rtp delay the time they can be used for judging as the third condition of losing step 5 shown as picture.

[0033] 6 process is not synchronizing/ desynchronizing condition:

Initiate synchronous thread.

[0034] to the first synchronous * between media in the condition of losing * processing steps are as follows: It does not delay of the media and the whole body of the delay time t and the rtp package. At the same inches the media buffer area can still receive new from the rtp package to the new of the rtp package to said step 2 is on the judgement processed it only needs to the packet is not to delay and it is not the same step of rtp package to the memory to start to submit request to zeng said buffer capacity to contain more rtp package. The integrity is rtp package to the delay of media then at time t in the waiting time of the rtp package to the group at the same time to the sending terminal sends feedback information notification sending terminal reduces the media packet frequency.

[0035] to the second synchronous information * the media desynchronizing treatment it comprises the steps as follows: The media buffering area in the rtp package the do not the whole time delay processing and it does not to the terminal sends feedback information the interception end *** to intercepts the dan delay but also can realize synchronization of the immediately according to step 2 in said method to process media is fast and *.

[0036] the third mixed * or the mixture is * firstly does not delay of media to the delay time t and the rtp package. At the same inches the media buffer area can still receive new from the rtp package to the new of the rtp package to said step 2 is on the judgement processed it only needs to the packet is not to delay and it is not the same step of rtp package to the memory to start to submit request to zeng said buffer capacity to contain more rtp package. The integrity is rtp package to the delay of media then at time t in the waiting time of the rtp package group from the sending terminal sends feedback information notification sending terminal reduces the media packet frequency. And at the same time the detecting end *** dan intercepts the individual to delay but also can realize synchronization of the immediately according to step 2 in said method to process media is fast and *.

[0037] to the three conditions to make the synchronization and after processing if the displaying picture 6.

[0038] the waiting time t by the following two states determined: If there is the delay of media constantly receives new to rtp packet and the time ti to reach the buffer area of the upper limit for the integrity of rtp package to the delay of media it does not finish the media block mapping at the same time the time t = tl; If there is the delay of media body does not reach the buffer area the upper limit h when the integrity of rtp package to the delay of media in the time t2 has been completed media block mapping at the same time the time t = t2. Media block mapping at the same time it is entering the buffer area of each rtp packets can be found relative to the other end of the media mapping but it does not ensure that each mapping each piece is rtp package there is no loss of the point-to-point mapping *** is special so it has little appear *.

[0039] rtp audio video frequency package after the first synchronization processing is eliminated after the in the network transmission media is generated by the shake and media between the time delay difference between the language * to rtp packet when the audio video frequency media has finished the initial * the synchronization of this utility model can ensure the subsequent the avs system after decoding to carry out accurately synchronous playback.

[0040] the operation process with the rtp package to the time to carry out treatment so as to fast deal can be different condition of losing *.

[0041] the audio buffer it is mainly comprised of audio frequency frame monitoring terminal and audio frequency mapping the two modules. The two modules are cooperated working mechanism of the following:

Audio frequency frame listener *** module it mainly comprises *** zhang chi to but also can realize synchronization of rtp audio frequency package of packet sequence number of the surface of the sequence number in the table from small to big according to the order of storing. When receiving *** new of the rtp audio frequency package is the package the sequence number and the surface of the sequence number from small to big according to the sequence by a comparison. If the sequence number and the surface of the sequence number is different and less than the minimum values in the invention is that the late and can realize synchronization of the package bag to directly throw away it does not enter into the buffer area queue; If the sequence number and the surface of the sequence number is different which is larger than surface of the smallest common than the maximum of the invention is the packet is not to delay the packet the packet going into buffer area analyzing the head field information preparing form a new audio block mapping; If the serial number and list of some sequence number is the same then it proves that the delay is the only can be also can realize synchronization of audio frequency package the rtp package to the buffer area preparing fast determination in the queue in a position.

[0042] late but also can realize synchronization of rtp audio frequency package quickly determining in the queue in the position of the method of: Firstly finding a missing sequence number of the mark of mapping block then transferring the packet sequence number and the mapping module lacking mark the sequence number and comparing if it is the same then it proves that the packet belonging to the mapping module which is fixed position; If it is different is connected with the upper and lower two *** comprising losing sequence number of the mark of mapping block lack mark the sequence number comparing the determining the position. So as to realize the audio media by fast synchronization.

[0043] on the surface of the two states in real time update: The first one is that when forming *** a new audio the mapping module mapping module is detecting whether or not block or in adjacent block is set between the lacking of rtp audio frequency package sequence number at the same time checking whether the neighbouring mapping module which has been make losing sequence number mark; If there is the sequence number is added to the deletion serial number mark in the same time the sequence number transmitted to the audio signal hearing *** end of the module to update list the list zeng the one of the lost packet sequence number; If there is not be lost serial number mark and it does not to the interception *** end of the surface of the module transmits the sequence number loss. *** is that when an audio frequency mapping module to carry out the audio frequency package inches or rtp and the mapping module still has shortage of the serial number mark the deficiency of mark the sequence number transmitted to the audio signal hearing *** end of the surface of the middle to update the deleting list and the losing sequence number of the same sequence number. So as to finish the updating.

0044 ] and [ the corresponding to the video buffer region is also set with corresponding to the two modules such as image i show and the audio frequency is different from that of the working mechanism.

[0045] the content is combined with the main body of the preferred embodiment of this invention the detailed *** step the invention can not be determined this invention claims a concrete actualizing of only limited in the specification. To the invention belongs to technical field of the common technical personnel to said it is not separated from the invention is designed under the premise of it also can make several is single push and pull or replace all the as when it belongs to the invention claims a protection range.