E1 / IP video conference protocol conversion device and system thereof

Abstract

The invention relates to the technical field of protocol conversion, in particular to an E1 / IP video conference protocol conversion device and system, and the system comprises a frame structure mapping module, a signaling adaptation module, a media stream packaging module, a buffer area control module and a synchronous coordination module. According to the invention, the synchronization mark and the load field of the physical layer framing structure are extracted, the maximum transmission unit parameter is combined, the frame packet boundary is accurately identified, the cross-network data positioning accuracy is improved, the call control mapping relation is established based on key field identification, and the session continuity between heterogeneous signaling is enhanced; the audio and video sampling rate and timestamp fundamental frequency are matched and verified, the consistency of media stream transmission time delay is guaranteed, interface throughput and time slot occupation changes are dynamically monitored, a buffer regulation and control instruction is generated, and the data transmission stability under burst flow is improved; the synchronization accuracy of the protocol conversion system in a heterogeneous network environment is realized, and the reliability of real-time services such as video conferences and the like is enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of protocol conversion, in particular to an E1 / IP video conference protocol conversion device and system thereof. BACKGROUND

[0002] The technical field of protocol conversion includes data interaction and adaptation mechanism between different transmission protocols in communication networks, involving protocol stack analysis, conversion rule definition and cross-platform data stream reorganization in heterogeneous network environment. Its core content focuses on solving the differences between traditional telecommunication network and Internet protocol in frame structure, signaling interaction and transmission rate, and realizing the compatibility of time-slotted bearing of E1 line and packetized transmission of IP network through establishing intermediate layer conversion logic. The systematic technical field covers bottom physical interface adaptation, protocol data unit analysis, dynamic matching of conversion rules and integrity verification of converted data, and needs to rely on standardized protocol framework to realize end-to-end transparent transmission, while meeting the strict requirements of real-time business on delay and jitter.

[0003] Among them, the E1 / IP video conference protocol conversion system refers to the protocol intercommunication obstacles of E1 circuit switching network and IP packet switching network in the video conference scenario, which adopts technical means of frame structure mapping, signaling adaptation and media stream encapsulation. This technical matter covers the conversion rule formulation of E1 physical layer framing format to IP data packet payload, specifically by extracting H.221 / H.242 control signaling in E1 time slot and converting it into SIP / H.245 protocol message, and at the same time, encapsulating G.711 / G.722 audio stream and H.261 / H.264 video stream into RTP, realizing the synchronous establishment and maintenance of media channel based on double stack protocol.

[0004] In the face of circuit switching and packet switching architecture differences, the existing technology relies on fixed rule matching to identify the frame and packet boundary, lacks dynamic adjustment mechanism, and is easy to cause data misplacement due to boundary drift under complex link conditions, resulting in media stream synchronization error. In terms of signaling adaptation, the existing system mostly relies on static conversion of control signaling field, and it is difficult to establish effective cross-protocol call context mapping relationship, resulting in interruption or repeated negotiation of signaling flow, affecting call establishment efficiency and stability. In media stream encapsulation, the real-time alignment of transmission protocol time base frequency and sampling parameters is ignored, resulting in synchronization deviation of audio and video data, and further causing playback delay and lip sync problem. In the traffic burst scenario, no buffer control strategy based on throughput fluctuation trend is established, which cannot dynamically balance data accumulation and packet loss risk, affecting the overall link transmission quality. In addition, the existing technology lacks a cooperative response mechanism for redundant check errors and clock deviation in the transmission process, and the system mostly relies on manual restart or static fault tolerance logic under abnormal conditions, which is difficult to guarantee the stability of protocol conversion under long-time operation. The above shortcomings are particularly obvious in high real-time scenarios such as high-definition video conferencing, seriously restricting the practicability and service quality guarantee capability of the system. SUMMARY

[0005] The purpose of the present application is to solve the problems existing in the prior art and to provide an E1 / IP video conference protocol conversion device and system.

[0006] In order to achieve the above purpose, the present application adopts the following technical scheme: an E1 / IP video conference protocol conversion system comprises:

[0007] The frame structure mapping module detects the zeroth time slot synchronization flag of the physical layer frame format and the network maximum transmission unit value, extracts the cyclic redundancy check code and the payload length field, judges the alignment state of the time slot boundary and the data packet start position, and generates a frame-to-packet alignment identifier;

[0008] The signaling adaptation module identifies the call reference value field and the session identifier field within the time slot based on the frame-to-packet alignment identifier, extracts the service digital network call control information and establishes a mapping relationship, and generates a cross-protocol signaling mapping table;

[0009] The media stream encapsulation module receives pulse code modulation audio code stream and video encoding frame data according to the cross-protocol signaling mapping table, judges the matching state of the real-time transport protocol timestamp base frequency and the media sampling rate, and generates a timestamp synchronization parameter;

[0010] The buffer control module monitors the time slot occupancy rate and the interface throughput fluctuation trend in combination with the timestamp synchronization parameter, judges the dynamic balance state of the occupancy rate and the throughput, and generates a buffer water level control instruction;

[0011] The synchronization coordination module calls the buffer water level regulation instruction, frame-to-packet alignment identification, cross-protocol signaling mapping table and timestamp synchronization parameter, checks cyclic redundancy check code error and clock time deviation event, and triggers a dual-stack cooperative control instruction.

[0012] As a further scheme of the application, the frame-to-packet alignment identification includes a zeroth time slot synchronization flag bit, a maximum transmission unit value, a cyclic redundancy check code, a payload length field, a time slot boundary offset, the cross-protocol signaling mapping table includes a call reference value, a session identification field, call control information, and a call type mapping rule, and the timestamp synchronization parameter includes a base frequency matching result, a timestamp increment step, and a fragmentation encapsulation rule.

[0013] As a further scheme of the application, the frame structure mapping module includes:

[0014] The synchronization identification detection submodule detects the synchronization flag bit of the zeroth time slot of the physical layer framing format, verifies the continuity of the binary sequence, compares the length of the synchronization flag bit with the integer multiple of the transmission unit value in combination with the network maximum transmission unit value configuration parameter, and generates a synchronization reference value;

[0015] The payload analysis submodule locates the frame structure starting position based on the synchronization reference value, intercepts the cyclic redundancy check code field and the payload length field according to the maximum transmission unit value, analyzes and converts the binary data of the check code and the payload length into a standard format, and generates a payload check coefficient and an actual payload amount;

[0016] The time slot alignment determination submodule determines the data packet starting position in combination with the payload check coefficient and the actual payload amount, calls the synchronization reference value to define the time slot boundary range, compares the time slot boundary offset and the data packet starting offset difference value, and if the difference value meets a preset time slot alignment threshold, a state is determined, and a frame-to-packet alignment identification is generated.

[0017] As a further scheme of the application, the signaling adaptation module includes:

[0018] The field identification extraction submodule detects the frame-to-packet alignment identification, locates the starting and ending positions of the call reference value field and the session identification field in the time slot, extracts the numerical values in the fields, compares the field length with a preset field length threshold, screens a numerical value set meeting the length threshold, and generates a field identification set.

[0019] The mapping relationship construction submodule calls the field identification set, matches the call reference value field value with the session identification field value, establishes a corresponding relationship, divides mapping relationship groups according to the protocol type code in the service digital network call control information, and generates a call mapping association table;

[0020] The signaling mapping generation submodule integrates the protocol type and the time sequence code in the service digital network call control information based on the call mapping association table, arranges the cross-protocol call reference value and the session identification according to the time sequence code in ascending order, and generates a cross-protocol signaling mapping table.

[0021] As a further scheme of the application, the media stream encapsulation module comprises:

[0022] The data receiving and analyzing submodule calls the cross-protocol signaling mapping table, receives the pulse code modulation audio code stream and the video encoding frame data, extracts the audio sampling rate, the video frame rate and the real-time transport protocol timestamp base frequency, and respectively stores the audio and video sampling rates and the timestamp base frequency;

[0023] The timestamp matching and judging submodule compares the value relationship between the audio and video sampling rates and the timestamp base frequency based on the audio and video sampling rates and the timestamp base frequency, judges whether the value relationship meets a preset synchronization threshold range, marks a matching state if the value relationship meets the preset synchronization threshold range, otherwise marks a mismatching state, and generates a timestamp matching state.

[0024] The synchronization parameter generation submodule generates a reference parameter based on the timestamp base frequency and the audio and video sampling rates if the timestamp matching state is the matching state, or recalibrates the corresponding relationship between the timestamp base frequency and the audio and video sampling rates if the timestamp matching state is the mismatching state, and generates a timestamp synchronization parameter.

[0025] As a further scheme of the application, the buffer control module comprises:

[0026] The time synchronization calibration submodule obtains buffer timestamp data based on the timestamp synchronization parameter, aligns the device local clock and the global clock in a time sequence, calculates a timestamp deviation mean value, performs incremental compensation on the local clock setting based on the deviation mean value, and generates a synchronization difference value.

[0027] The fluctuation trend monitoring submodule calls the synchronization difference value, monitors the number of data packets occupied in a unit time slot and the interface transmission byte amount, respectively calculates a time slot occupancy rate sliding average value and a throughput change rate, extracts the fluctuation correlation characteristics of the occupancy rate and the throughput, and generates a fluctuation correlation degree.

[0028] The dynamic balance judgment sub-module sets a time slot occupancy rate boundary and a throughput fluctuation tolerance range based on the synchronization difference value and the fluctuation correlation degree, judges whether the current occupancy rate exceeds the boundary and the correlation degree is outside the tolerance range, adjusts the buffer read-write rate proportion according to the deviation direction if the condition is met, and generates a buffer water level control instruction.

[0029] As a further scheme of the present application, the specific calculation formula of the time stamp deviation mean is:

[0030]

[0031] wherein, represents the synchronization deviation mean of the corrected weighted local and global time, N represents the number of time stamp pairs participating in the deviation statistics, represents the i-th local device clock time stamp, represents the i-th global clock time stamp, represents the j-th network delay measurement value, M represents the number of network delay measurement samples, and γ represents a synchronization adjustment proportion factor, which is unit-independent.

[0032] As a further scheme of the present application, the synchronization coordination module comprises:

[0033] The frame packet alignment sub-module integrates the buffer water level control instruction, the frame-to-packet alignment state identifier, the cross-protocol signaling mapping relationship table and the time stamp synchronization parameter, detects the position offset of the frame boundary marker and the packet start marker, extracts the current check bit sequence of the cyclic redundancy check code, calculates the difference between the offset and a preset packet alignment tolerance threshold, and generates an alignment check rate.

[0034] The signaling timing control sub-module calls the alignment check rate, extracts the timing priority marker of the cross-protocol field, performs linear interpolation compensation on the reference clock deviation value in time stamp synchronization, compares the buffer water level value with a preset water level threshold at the same time, and generates a synchronization control amount.

[0035] The dual stack cooperative generation sub-module accumulatively counts the number of trigger times of the cyclic redundancy check code error event based on the synchronization control amount, calculates the ratio of the clock time correction deviation value to the upper limit of the synchronization tolerance, combines the statistical value and the proportion according to a set proportion, and generates a dual stack cooperative control instruction.

[0036] As a further scheme of the present application, the specific calculation formula of the position offset of the frame boundary marker and the packet start marker is:

[0037]

[0038] wherein, Δ' posrepresents a position offset adjustment value, n represents the total number of frames in the sampling window, w i represents the payload bit width of the i-th frame, p i represents the periodic frame identification count in the i-th frame, b i represents the starting bit position of the i-th frame frame boundary marker, k i represents the number of protocol layer mapping fields in the i-th frame.

[0039] Compared with the prior art, the application has the advantages and positive effects that:

[0040] In the application, by extracting the synchronization mark and the payload field of the physical layer framing structure, combining the maximum transmission unit parameter, accurately identifying the frame packet boundary, improving the positioning accuracy of cross-network data, establishing a call control mapping relationship based on key field identification, enhancing the session persistence between heterogeneous signaling, matching and verifying the audio / video sampling rate and timestamp base frequency, ensuring the consistency of media stream transmission delay, dynamically monitoring the interface throughput and time slot occupation change, generating buffer control instructions, improving the data transmission stability under burst traffic, and through parameter linkage and state closed loop logic, the protocol conversion system realizes synchronization accuracy in a heterogeneous network environment, and enhances the reliability of real-time services such as video conference. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 The system flowchart of the application

[0042] Figure 2 The system block diagram of the application. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the application clearer, the application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the application and do not limit the application.

[0044] In the description of the application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the application. In addition, in the description of the application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0045] Please refer to Figures 1-2 An E1 / IP video conference protocol conversion system comprises:

[0046] The frame structure mapping module detects the zeroth time slot synchronization flag bit of the physical layer framing format and the network maximum transmission unit value, extracts the frame structure cyclic redundancy check code and the data packet payload length field, judges the alignment state of the time slot boundary and the data packet starting position, and generates a frame-to-packet alignment identifier;

[0047] (Supplementary explanation: The alignment identifier is determined by comparing the logical relationship between the time slot boundary flag bit and the starting position of the IP packet payload. If they overlap within a predetermined tolerance range, it is identified as successful alignment);

[0048] The signaling adaptation module identifies the call reference value field and the session identifier field in the time slot based on the frame-to-packet alignment identifier, extracts the service digital network call control information, establishes a call identifier mapping relationship, and generates a cross-protocol signaling mapping table;

[0049] (Supplementary explanation: The call identifier mapping relationship is constructed by comparing the logical association between the circuit switched signaling field and the packet switched signaling field, such as the matching relationship between the call type and the media type);

[0050] The media stream encapsulation module receives pulse code modulation audio code streams and video encoding frame data according to the cross-protocol signaling mapping table, judges the matching state of the real-time transport protocol timestamp base frequency and the media sampling rate, and generates timestamp synchronization parameters;

[0051] (Supplementary explanation: The matching state is determined by verifying whether the timestamp base frequency is an integer multiple of the audio sampling rate or the video frame rate. If it is, valid synchronization parameters are generated);

[0052] The buffer control module combines the timestamp synchronization parameters, monitors the time slot occupancy rate and the interface throughput fluctuation trend, judges the dynamic balance state of the occupancy rate and the throughput, and generates buffer water level control instructions;

[0053] (Supplementary explanation: The dynamic balance state is determined by observing the inverse correlation between the occupancy rate growth rate and the throughput decline rate. If it is unbalanced, water level control is triggered);

[0054] The synchronization coordination module integrates the buffer water level control instructions, the frame-to-packet alignment state identifier, the cross-protocol signaling mapping relationship table, and the timestamp synchronization parameters, detects cyclic redundancy check code error events and clock time deviation alarm events, and generates dual-stack cooperative control instructions;

[0055] (Supplementary explanation: The cooperative control instructions are triggered by verifying the concurrent state of the error events and the clock deviation events. For example, compensation is activated when there are three consecutive verification errors and the deviation exceeds the preset threshold).

[0056] The frame-to-packet alignment identifier includes a zeroth time slot synchronization flag bit, a maximum transmission unit value, a cyclic redundancy check code, a payload length field, and a time slot boundary offset. The cross-protocol signaling mapping table includes a call reference value, a session identification field, call control information, and a call type mapping rule. The timestamp synchronization parameter includes a base frequency matching result, a timestamp increment step, and a fragmentation encapsulation rule. The buffer water level regulation instruction includes an occupancy rate threshold, a throughput fluctuation interval, and a balance state determination rule. The dual-stack cooperative control instruction includes a number of verification errors, a clock deviation threshold, and a compensation trigger condition.

[0057] Referring to Figure 2 The frame structure mapping module includes:

[0058] The synchronization identifier detection submodule detects the synchronization flag bit of the zeroth time slot of the physical layer framing format, verifies the continuity of the binary sequence, compares the length of the synchronization flag bit with the integer multiple of the transmission unit value based on the network maximum transmission unit value configuration parameter, and generates a synchronization reference value.

[0059] During the execution of the synchronization identifier detection submodule, the bit stream transmitted by the physical layer needs to be received first, and the starting position of the zeroth time slot is located. This position is usually provided by the clock synchronization logic of the physical layer, and the first recognizable boundary point can be defined through this logic. Next, a preset synchronization flag bit template, such as a sequence composed of alternating high and low levels, is used as a reference object, and the actual bit sequence extracted in the zeroth time slot is analyzed bit by bit. When comparing bit by bit, a bitwise XOR operation can be used to determine whether each bit is the same. According to the preset matching threshold, for example, at least six bits need to be consistent in eight bits to be considered a match. After recognition, to confirm that the flag bit has repeatability in multiple consecutive time slots, the number of occurrences of the synchronization flag in multiple time slots after the current time slot is detected one by one. If the matching synchronization flag bit sequence appears in more than seven of the ten consecutive time slots, it is determined to have continuity. Subsequently, the network maximum transmission unit value, i.e., the maximum data length set in the communication protocol, is introduced. For example, if the set value is 1500 bytes, it is converted to 12,000 bits. The length of the synchronization flag bit is calculated by the number of bits corresponding to the maximum transmission unit value. If it is an integer, the length of the synchronization flag bit is considered to meet the transmission structure requirements, and its length is used as a reference basis for dividing the frame boundary. For example, if the synchronization flag length is 12,000 bits, which is equal to the integer multiple of the maximum transmission unit value, then this length is the synchronization reference value. This reference value records the position of the first successful identification of the synchronization flag and is used as a positioning reference for subsequent frame structure analysis.

[0060] The payload analysis submodule positions the starting position of the frame structure based on the synchronization reference value, extracts the cyclic redundancy check code field and the payload length field based on the maximum transmission unit value, analyzes the binary data of the check code and the payload length and converts them to a standard format, and generates a payload check coefficient and an actual payload amount.

[0061] The operation of the load analysis submodule is based on the synchronization reference value, which represents the position information of the first occurrence of the synchronization flag in the bit stream. This position is usually recorded as the starting point of the frame structure, from which various fields in the frame structure are located. The length of each frame of data is set according to the maximum transmission unit value, such as 1500 bytes, which defines the length of each frame as twelve thousand two bits. Within this length interval, the cyclic redundancy check code field is extracted from the predetermined offset position, which generally occupies a fixed sixteen bits, such as between the eighth and twenty-fourth bits after the start of the frame. Next, the load length field is read, which is generally sixteen bits and located after the check field. After reading, these two fields are converted to decimal respectively, the check code field can be converted to the standard format of hexadecimal encoding and then to the decimal value by looking up the table, and the load length field is directly converted by unsigned binary. The obtained decimal check code and load length are combined to calculate the check coefficient, that is, the check code value is divided by the load length value to obtain the check coefficient, which is used to describe the data integrity status. If the check code field value is seven thousand four hundred thirty-nine and the load length field value is two thousand twenty-four, the check coefficient can be calculated to be about three point six seven. The coefficient combined with the actual load length together constitutes the load amount information, which provides the basis for subsequent data alignment.

[0062] The time slot alignment determination submodule combines the load check coefficient and the actual load amount to determine the starting position of the data packet, calls the synchronization reference value to define the time slot boundary range, compares the difference value between the time slot boundary offset and the data packet starting offset, and if the difference value meets the preset time slot alignment threshold, the state is determined, and the frame to packet alignment identifier is generated;

[0063] The time slot alignment determination submodule needs to analyze the position of the data packet in the frame according to the load check coefficient and the actual load length. First, based on the frame start offset, the expected starting position of the data packet is calculated according to the previously analyzed load length. For example, if the frame start offset is zero, the starting position of the data packet in the bit stream should be at 12,000 bits, indicating that a maximum transmission unit has been fully loaded. Next, according to the time slot boundary parameters recorded in the synchronization reference value, such as the definition length of each time slot being 2,000 bits, the offset can be determined to be located in the sixth time slot boundary area. At this time, the difference between the offset value and the starting position of the current time slot boundary is calculated. If the offset value is exactly an integer multiple of 2,000, it is completely aligned with the time slot boundary. The system sets a set of allowed error range as the time slot alignment threshold, for example, set to plus or minus 100 bits. As long as the calculated offset difference falls within this interval, it can be determined that the current data packet is located at the valid time slot boundary, and an identification indicating the alignment state of the frame and the packet can be generated. The identification is represented in the form of a Boolean value, indicating whether the data can directly enter the subsequent processing flow. The above processing logic is applicable to high-speed data transmission scenarios such as optical communication, wireless base station and satellite link environments. In these situations, the frame structure and physical layer time slot need to be strictly matched to support efficient processing of data streams.

[0064] Please refer to Figure 2 The signaling adaptation module includes:

[0065] The field identification extraction submodule detects the frame-to-packet alignment identification, locates the starting and ending positions of the call reference value field and the session identification field within the time slot, extracts the values in the fields, compares the field length with the preset field length threshold, selects the value set that meets the length threshold, and generates a field identification set.

[0066] The field identification extraction submodule first performs a comparison operation on the packet alignment identifier in the communication protocol frame structure, obtains the starting marker of each frame in the original data stream, and compares the packet alignment byte mode defined by the protocol to confirm whether the frame meets the alignment requirement. After completing the alignment confirmation, enter the time slot field positioning stage, mark the specific position of the time slot field in the frame through the pre-defined frame structure offset information, for example, the total length of the frame is 128 bytes, the time slot field is usually located between the 24th and 32nd bytes, and the call reference value field and the session identifier field which appear in turn after the time slot field start at the 33rd and 37th bytes and end at the 36th and 44th bytes. The extraction stage extracts the corresponding byte segment in the original frame according to the start and end positions of the field, reads its binary or hexadecimal value and converts it into a standard integer format, obtains the value, calculates the byte length occupied by the value, and judges the actual field length through the offset between the start position and the end position. For example, the field from the 33rd byte to the 36th byte contains 4 bytes, which is equal to a 32-bit value. After completing the field extraction, compare the field length with the set minimum and maximum length thresholds, retain the field data whose length is within the threshold range, if the length of the field is 6 bytes and the threshold range is set to 4 to 8 bytes, the field is valid, if the length is 9 bytes, it is excluded. Assign a unique identification number to the valid field set after screening in sequence to generate a field identification set.

[0067] The mapping relationship construction submodule calls the field identification set, matches the call reference value field value with the session identifier field value, establishes a corresponding relationship, divides the mapping relationship groups according to the protocol type code in the business digital network call control information, and generates a call mapping association table;

[0068] The mapping relationship construction submodule iterates through the generated field identification set one by one, pairs each call reference value field value with the corresponding session identifier field value one by one, associates the storage position of the field in the data structure through the field index number and retrieves the matching pair accordingly. Each time a pair is constructed, a group of field value combinations is recorded, and grouping processing is performed depending on the protocol type code field. The protocol type field is usually provided by the business digital network call control information, for example, the code value of 03 represents that the field belongs to the Q.931 protocol, and the code value of 05 represents that it belongs to the PRI protocol. According to these code values, the field pairing results are divided into multiple mapping groups to form a group structure. For example, all field pairing records with code 03 are saved in the set marked as Group03, and the code 05 is saved in the Group05 set. Each group saves several pairing items, including the call reference value and the corresponding session identifier field value, and the structure is like this: Group number, call reference value, session identifier. After completing the grouping, all records are written into the mapping association data table structure.

[0069] The signaling mapping generation submodule generates a cross-protocol signaling mapping table based on a call mapping association table, integrates the protocol type and timing code in the integrated services digital network call control information, arranges the cross-protocol call reference value and session identification in ascending order according to the timing code, and generates the cross-protocol signaling mapping table.

[0070] When the signaling mapping generation submodule calls the mapping association table, the field pairs in each group are preferentially subjected to timing sequence sorting processing, and the timing code field added in the integrated services digital network call control information is used as a sorting key. Each field pair record usually contains a set of timing information identifiers, such as TS001, TS002, and the like, indicating the generation order of the record. The module sorts all records in ascending order according to the numerical values of these identifiers. When the data volume is small, the method of successive comparison is used to sequentially judge the timing relationship between two field records, and the order is exchanged if the order is not satisfied. After the sorting in the group is completed, the records in each protocol type group are summarized to generate a cross-protocol signaling mapping data set with a unified structure, and each record contains core information such as the protocol type identifier, the sorted timing code, the call reference value, and the session identification field. The finally formed mapping structure is used to describe the corresponding relationship between the call fields of different protocols, and is used as a key parameter to support the signaling scheduling in a multi-protocol environment.

[0071] Referring to Figure 2 , the media stream encapsulation module comprises:

[0072] The data receiving and analyzing submodule calls the cross-protocol signaling mapping table, receives the pulse code modulation audio code stream and the video encoding frame data, extracts the audio sampling rate, the video frame rate, and the real-time transport protocol timestamp base frequency, and stores them as the audio / video sampling rate and the timestamp base frequency, respectively.

[0073] The data receiving and analyzing submodule first identifies the frame header information in each frame of audio data according to the data format of the audio code stream after calling the cross-protocol signaling mapping table, extracts the audio sampling rate information through the specified bit in the frame header, and checks the audio frame length and byte rate to ensure the validity of the extraction result. The video encoding frame is further analyzed to obtain the video frame rate by calculating the number of frames per unit time through the PTS field, i.e., the display timestamp, in consecutive frames of the video stream. If the time interval between adjacent frames is constant at about 33 milliseconds, the frame rate is determined to be 30 frames per second. The timestamp field in the data packet header is then analyzed to confirm the base frequency size by analyzing the change increment of the timestamp field in consecutive data packets. For example, if the timestamp increases by 90000 units per second, the base frequency is set to 90000. The audio sampling rate, video frame rate, and timestamp base frequency are saved to the parameter management area for subsequent module reading and use. For example, if the audio frame header identification is 48kHz, the video consecutive frame display time interval is 33 milliseconds, and the timestamp increment speed is stable at 90000 units per second in a single sampling, the audio sampling rate is determined to be 48kHz, the video frame rate is determined to be 30 frames per second, and the timestamp base frequency is determined to be 90000.

[0074] The timestamp matching judgment submodule compares the numerical relationship between the audio and video sampling rates and the timestamp base frequency to determine whether they meet the preset synchronization threshold range. If they meet the threshold, they are marked as matching, otherwise they are marked as mismatching, and a timestamp matching state is generated.

[0075] The timestamp matching judgment submodule performs a judgment process based on the extracted audio sampling rate, video frame rate, and timestamp base frequency. First, the duration of each audio sample interval is inversely calculated based on the audio sampling rate, for example, a sampling rate of 48000 corresponds to an interval of about 20.8 microseconds. The duration of each frame is estimated using the video frame rate, for example, a frame rate of 30 frames per second corresponds to a time of 33.3 milliseconds. Combining the timestamp base frequency information, each time duration is converted into a timestamp increment unit, for example, an audio frame is converted into about 1.8 timestamp units and a video frame is converted into about 3000 timestamp units. Next, the ratio of the audio and video timestamp increments is calculated at multiple time points to determine whether it is close to the theoretical ratio range. For example, if the ratio between two increments is 1600, it needs to be determined whether it is within the acceptable range of 1550 to 1650. If it is within the acceptable range, it is determined to be in a timestamp matching state. If it is outside the range, it is marked as mismatching. The comparison is performed in multiple consecutive calculation windows. If the number of matching times exceeds a certain number, for example, more than 8 times out of 10, the overall state is identified as matching. Otherwise, it is identified as mismatching. The judgment result is used to guide the subsequent synchronization processing operation.

[0076] The synchronization parameter generation submodule generates baseline parameters based on the timestamp matching status. If the timestamp is matched, it generates baseline parameters based on the timestamp base frequency and the audio / video sampling rate. If the timestamp is mismatched, it recalibrates the correspondence between the timestamp base frequency and the audio / video sampling rate to generate timestamp synchronization parameters.

[0077] The synchronization parameter generation submodule sets parameters based on the received timestamp matching results. When a match is determined, it directly uses the existing audio sampling rate, video frame rate, and timestamp base frequency to establish a set of reference parameters for synchronization mapping. By recording the timestamp units corresponding to each or several audio frames, and the relationship between video frames and timestamps, the playback end can calibrate the playback rhythm accordingly. For example, the audio frame duration is approximately 20.8 microseconds, corresponding to a timestamp unit of approximately 1.8, and the video frame duration is approximately 33 milliseconds, corresponding to a timestamp unit of 3000. That is, the mapping relationship is constructed so that one frame is advanced every 3000 timestamp units. The video feed advances simultaneously with the corresponding audio segment. If a mismatch is detected, the original parameters are not used directly. Instead, a new estimation is performed, reading continuous frame data and re-measuring the time difference between frames. The actual frame rate is calculated based on this time difference and compared with the original setting value to confirm the direction and magnitude of the offset. For example, if the timestamp between consecutive frames is 2940, the estimated frame interval is approximately 32.6 milliseconds, which translates to a frame rate of approximately 30.6 frames per second. This frame rate is then processed using a smoothing algorithm to obtain a more stable value, which is updated to the new synchronization parameters. Finally, an updated timestamp mapping structure is generated and recorded as the current synchronization reference for use by subsequent modules or for archiving.

[0078] Please see Figure 2 The buffer control module includes:

[0079] The time synchronization calibration submodule obtains buffer timestamp data based on timestamp synchronization parameters, aligns the device's local clock with the global clock in time series, calculates the average timestamp deviation, performs incremental compensation on the local clock settings based on the average deviation, and generates a synchronization difference value.

[0080] The specific formula for calculating the mean timestamp deviation is as follows:

[0081]

[0082] in, This represents the average synchronization deviation between local and global time after adjustment and weighting, where N represents the number of timestamp pairs included in the deviation statistics. Represents the timestamp of the i-th local device clock. Represents the i-th global clock timestamp. M represents the number of network delay measurement samples, γ represents the synchronization adjustment proportion factor, which has unit independence;

[0083] Formula details and formula calculation derivation process:

[0084] Parameter description:

[0085] N: The number of timestamp pairs participating in bias statistics is determined by the number of timestamp pairs collected by the system within the synchronization period.

[0086] The i-th local device clock timestamp is obtained through the device local clock record.

[0087] The i-th global clock timestamp is obtained through the synchronization signal.

[0088] M: The number of network delay measurement samples is determined by the number of network delay measurements within the synchronization period.

[0089] The j-th network delay measurement value is obtained through the network delay measurement tool.

[0090] γ: The synchronization adjustment proportion factor is set according to the system's requirements for synchronization accuracy and fluctuates with network state changes.

[0091] Parameter value setting:

[0092] N = 5: The system has collected 5 pairs of timestamps within the synchronization period.

[0093] M = 3: Network delay has been measured 3 times within the synchronization period.

[0094] γ = 0.8: Set according to the system's requirements for synchronization accuracy.

[0095] Collected timestamp data:

[0096]

[0097]

[0098] Measured network delay data:

[0099]

[0100] Calculation process:

[0101] Calculate the average value of each pair of timestamps:

[0102]

[0103] Calculate the average value of network delay:

[0104]

[0105] Calculate network delay adjustment value:

[0106]

[0107] Add network delay adjustment value to the average of each pair of timestamps:

[0108] 100.001 + 0.2 = 100.201 ms;

[0109] 200.0015 + 0.2 = 200.2015 ms;

[0110] 300.0005 + 0.2 = 300.2005 ms;

[0111] 400.002 + 0.2 = 400.202 ms;

[0112] 500.001 + 0.2 = 500.201 ms;

[0113] Calculate the final synchronization deviation average:

[0114]

[0115] The result shows that the average synchronization deviation between the local clock and the global clock is 300.2012 milliseconds, indicating the average deviation of the local clock relative to the global clock under the current network conditions and synchronization settings. This value can be used to adjust the local clock settings to achieve more accurate time synchronization.

[0116] The fluctuation trend monitoring sub-module calls the synchronization difference value, monitors the number of data packet occupancy and the interface transmission byte amount in the unit time slot, respectively calculates the sliding average of the time slot occupancy rate and the throughput change rate, extracts the fluctuation correlation characteristics of the occupancy rate and the throughput by combining the time window superposition method, and generates the fluctuation correlation degree;

[0117] The process executed by the fluctuation trend monitoring submodule needs to combine the synchronization difference data obtained in advance. In a fixed time period, the total number of data packets entering in a unit time slot and the number of data bytes transmitted by the interface are recorded to form an observation sequence arranged by time. By setting a sliding window, a certain number of observation values are selected regularly to calculate the average occupation degree of the data stream in the current time slot and estimate the change speed of the interface data throughput. Taking the maximum number of packets that can be accommodated by the buffer as the benchmark, the average number of data packets in the current time period is calculated by ratio with the benchmark, and the current occupation rate is obtained. On this basis, the difference value of byte transmission between two consecutive time slots is divided by the time slot length, and the change amplitude of the transmission rate is obtained. Then, the occupation rate and the throughput rate of multiple consecutive time periods are used to construct a joint change feature vector, and the vector is superimposed according to the weighted method to emphasize the influence of recent observation values on the current state. Finally, the statistical correlation between the two dimensions in the joint feature is evaluated, such as whether they fluctuate together or change in the opposite direction. When a strong linear relationship is observed, a fluctuation correlation index is output to judge the current data pressure stability of the system. In data communication equipment, especially in the scene of multi-port network equipment, this module can assist in identifying the potential correlation between data pressure fluctuation and channel utilization, which is helpful for analyzing the initial trend of potential bottleneck formation.

[0118] The dynamic balance judgment submodule sets the time slot occupation rate boundary and the throughput fluctuation tolerance range based on the synchronization difference value and the fluctuation correlation degree, judges whether the current occupation rate exceeds the boundary and the correlation degree is outside the tolerance range, and if the conditions are met, adjusts the read-write speed ratio of the buffer according to the deviation direction to generate buffer water level control instructions;

[0119] The dynamic balance determination sub-module jointly evaluates the synchronization difference value and the fluctuation correlation index, sets a reasonable resource usage range, including the minimum and maximum boundaries of the data occupancy ratio, and the allowed change range of the throughput. When the occupancy ratio is lower than the minimum value or higher than the maximum value, it is considered that the current system data flow load is not in the normal range, and whether the current throughput fluctuation is beyond the tolerance value is also checked. If the occupancy state is abnormal and accompanied by a large fluctuation amplitude, the correlation of the changes of the two is determined to be a non-stable state. At this time, according to the current time offset direction, it is judged whether the local clock is faster or slower than the global clock, so as to determine whether the data transmission has a backlog or idle tendency. Then the data reading and writing rate ratio of the buffer is adjusted. If it is judged that the writing rate is higher than the reading rate, the reading operation should be accelerated, and vice versa. The adjustment process is to set a control factor and multiply it by the time offset value obtained in the previous calculation to form a proportional change value, which is then added to the current transmission rate. The adjustment amplitude cannot be too large to avoid amplifying the system fluctuation, so when setting the adjustment coefficient, the system stability test value should be referred to, for example, it can be set to one ten-thousandth level. Finally, the control instruction containing the time identifier, the adjustment ratio and the new rate parameter is generated and sent to the buffer management module for dynamic adjustment of the buffer state. In the deployment of edge computing nodes with intensive data flow, this method can be used to ensure the running stability of high-frequency acquisition or push data flow in the local network.

[0120] Please refer to Figure 2 , the synchronization coordination module comprises:

[0121] The frame packet alignment sub-module integrates the buffer water level control instruction, the frame-to-packet alignment state identifier, the cross-protocol signaling mapping relationship table and the timestamp synchronization parameter, detects the position offset of the frame boundary marker and the packet start marker, extracts the current check bit sequence of the cyclic redundancy check code, calculates the difference between the offset and the preset packet alignment tolerance threshold, and generates an alignment check rate.

[0122] The specific calculation formula of the position offset of the frame boundary marker and the packet start marker is:

[0123]

[0124] Δ′ pos represents the position offset adjustment value, n represents the total number of frames in the sampling window, w i represents the effective payload bit width of the i-th frame, p i represents the periodic frame identifier count in the i-th frame, b i represents the starting bit position of the frame boundary marker of the i-th frame, k i represents the number of protocol layer mapping fields in the i-th frame.

[0125] Formula details and formula calculation derivation process:

[0126] Δ' pos represents the position offset adjustment value, n represents the total number of frames within the sampling window, w i represents the payload bit width of the i-th frame, p i represents the periodic frame identification count within the i-th frame, b i represents the starting bit position of the frame boundary marker of the i-th frame, k i represents the number of protocol layer mapping fields in the i-th frame.

[0127] The acquisition method of each parameter is as follows:

[0128] n: the total number of frames within the sampling window counted by the data acquisition system.

[0129] w i : the payload bit width of the i-th frame measured by the data acquisition system.

[0130] p i : the periodic frame identification count within the i-th frame counted by the data acquisition system.

[0131] b i : the starting bit position of the frame boundary marker of the i-th frame measured by the data acquisition system.

[0132] k i : the number of protocol layer mapping fields in the i-th frame counted by the data acquisition system.

[0133] The specific values are as follows:

[0134] n = 3;

[0135] Frame 1: w1 = 128 bits, p1 = 2, b1 = 16 bits, k1 = 4;

[0136] Frame 2: w2 = 256 bits, p2 = 3, b2 = 24 bits, k2 = 5;

[0137] Frame 3: w3 = 512 bits, p3 = 1, b3 = 8 bits, k3 = 6;

[0138] Substitute the above values into the formula for calculation:

[0139] Frame 1 calculation:

[0140]

[0141] Frame 2 calculation:

[0142]

[0143] Frame 3 calculation:

[0144]

[0145] The calculation results of the three frames are averaged:

[0146]

[0147] This result indicates that the position offset adjustment value Δ′ pos Approximately 104.3556 bits, representing the average positional offset between the frame boundary marker and the packet start marker within the sampling window. This value is used in subsequent steps to extract the current parity bit sequence of the Cyclic Redundancy Check (CRC) code and calculate the difference between the offset and the preset packet alignment tolerance threshold, ultimately generating the alignment check rate.

[0148] The signaling timing control submodule calls the alignment check rate, extracts the timing priority flags of cross-protocol fields, performs linear interpolation compensation on the reference clock deviation value in timestamp synchronization, and compares the buffer water level value with the preset water level threshold to generate synchronization control amount.

[0149] The signaling timing control submodule uses the previously obtained alignment check rate as a basis, calls the internal cross-protocol field parsing module to identify the protocol type and priority markers carried in the data packets. For example, after identifying the tag field of a specific protocol in a data block, it determines the priority level of the current field in scheduling according to predefined field priority rules, and extracts the current reference clock frequency and the clock frequency actually detected by the receiver from the system buffer. The difference between the two constitutes the current clock deviation parameter. Subsequently, by sampling data at certain time intervals, the deviations within multiple cycles are interpolated to compensate, thereby correcting the timestamp of the received data. Then, it compares the real-time water level value of the current receive buffer with the water level threshold set by the system to determine whether the current buffer is in a high or low state. If the water level value is too low, the difference is calculated and a synchronization control quantity is formed to drive the buffer data scheduling module to dynamically adjust the read and write rates. Taking the scenario of simultaneously accessing MPLS and traditional Ethernet traffic in an industrial communication gateway as an example, the field control of different protocol priorities and the real-time clock difference compensation can effectively stabilize the traffic rhythm and prevent buffer overload or blockage.

[0150] The dual-stack collaborative generation submodule accumulates and counts the number of times the cyclic redundancy check error event is triggered based on the synchronization control amount, calculates the ratio of the clock timing deviation value to the upper limit of the synchronization tolerance, and combines the statistical value and the ratio according to the set ratio to generate dual-stack collaborative control instructions.

[0151] The double stack cooperative generation sub-module analyzes the cyclic redundancy check sequence of each packet in the receiving data process according to the water level difference in the synchronous control quantity, and counts once when detecting a check abnormal event, records the error code event of the data packet in the cycle, accumulates all error numbers in the set time period and counts the total number of received data packets, and calculates the proportion relationship of error code occurrence. Then read the clock deviation data provided by the previous module, and compare with the maximum deviation value allowed by the synchronous control, and determine the current clock control state and the boundary difference set by the system through the comparison relationship. After that, the error code number and the deviation ratio are weighted and integrated, and different weight proportions are used to reflect the comprehensive state between the statistical results and the time deviation, and finally generate a value representing the current cooperative control state, and convert it into a control instruction recognized by the double stack system through the instruction coding mechanism, and transmit it to the lower control circuit. Taking the SDH and Ethernet multiplexing platform as an example, the system forms the regulation and control signal between the double protocol stacks through the periodic accumulation of error code data and the synchronous state, and establishes a stable bidirectional link management mechanism while ensuring the consistency of the transmission structure.

[0152] The above is only a preferred embodiment of the present application, and does not limit the present application in other forms. Any skilled person in the art can modify or change the above disclosed technical content to equivalent embodiments applied to other fields, but any simple modification, equivalent change and modification made according to the technical essence of the present application to the above embodiments without departing from the technical solution content of the present application still belongs to the protection scope of the present application.

Claims

1. An E1 / IP video conferencing protocol conversion system, characterized in that: The system includes: The frame structure mapping module detects the zeroth time slot synchronization flag bit and the network maximum transmission unit value of the physical layer frame format, extracts the cyclic redundancy check code and payload length field, determines the alignment status of the time slot boundary and the packet start position, and generates a frame-to-packet alignment identifier. Based on the frame-to-packet alignment identifier, the signaling adaptation module identifies the call reference value field and session identifier field within the time slot, extracts the service digital network call control information and establishes a mapping relationship to generate a cross-protocol signaling mapping table; The media stream encapsulation module receives pulse code modulation audio bitstream and video encoded frame data according to the cross-protocol signaling mapping table, determines the matching status between the real-time transmission protocol timestamp baseband and the media sampling rate, and generates timestamp synchronization parameters. The buffer control module combines the timestamp synchronization parameters to monitor the fluctuation trend of timeslot occupancy and interface throughput, determine the dynamic balance state of occupancy and throughput, and generate buffer level control instructions. The synchronization coordination module calls the buffer level control instruction, frame-to-packet alignment identifier, cross-protocol signaling mapping table and timestamp synchronization parameters, verifies cyclic redundancy check code errors and clock synchronization deviation events, and triggers dual-stack collaborative control instructions.

2. The E1 / IP video conferencing protocol conversion system according to claim 1, characterized in that: The frame-to-packet alignment identifier includes the zeroth time slot synchronization flag, maximum transmission unit value, cyclic redundancy check code, payload length field, and time slot boundary offset. The cross-protocol signaling mapping table includes call reference value, session identifier field, call control information, and call type mapping rules. The timestamp synchronization parameters include baseband matching result, timestamp increment step size, and fragmentation encapsulation rules. The buffer level control instructions include occupancy threshold, throughput fluctuation range, and balance state determination rules. The dual-stack collaborative control instructions include the number of verification errors, clock deviation threshold, and compensation trigger condition.

3. The E1 / IP video conferencing protocol conversion system according to claim 1, characterized in that: The frame structure mapping module includes: The synchronization flag detection submodule detects the synchronization flag bit of the zeroth time slot of the physical layer framing format, verifies the continuity of the binary sequence, and, in conjunction with the network maximum transmission unit value configuration parameter, compares the relationship between the synchronization flag bit length and the transmission unit value as an integer multiple, and generates a synchronization reference value. The load parsing submodule locates the starting position of the frame structure based on the synchronization reference value, extracts the cyclic redundancy check code field and the load length field according to the maximum transmission unit value, parses the binary data of the check code and the load length and converts them into a standard format, and generates the load check coefficient and the actual load amount. The time slot alignment determination submodule combines the load verification coefficient with the actual load amount to determine the starting position of the data packet, calls the synchronization reference value to define the time slot boundary range, compares the difference between the time slot boundary offset and the data packet starting offset, and if the difference meets the preset time slot alignment threshold, it determines the status and generates a frame to packet alignment identifier.

4. The E1 / IP video conferencing protocol conversion system according to claim 3, characterized in that: The signaling adaptation module includes: The field identification and extraction submodule detects the frame-to-packet alignment identifier, locates the start and end positions of the call reference value field and the session identifier field within the time slot, extracts the values ​​within the fields, compares the field length with a preset field length threshold, filters the set of values ​​that meet the length threshold, and generates a set of field identifiers. The mapping relationship construction submodule calls the field identifier set, matches the call reference value field value with the session identifier field value, establishes a corresponding relationship, divides the mapping relationship groups according to the protocol type encoding in the business digital network call control information, and generates a call mapping association table; The signaling mapping generation submodule, based on the call mapping association table, integrates the protocol type and timing code in the business digital network call control information, and arranges the cross-protocol call reference value and session identifier in ascending order of timing code to generate a cross-protocol signaling mapping table.

5. The E1 / IP video conferencing protocol conversion system according to claim 4, characterized in that: The media stream encapsulation module includes: The data receiving and parsing submodule calls the cross-protocol signaling mapping table to receive pulse code modulation audio bitstream and video encoded frame data, extracts audio sampling rate, video frame rate and real-time transmission protocol timestamp base frequency, and stores them as audio and video sampling rate and timestamp base frequency respectively. The timestamp matching judgment submodule compares the numerical relationship between the audio and video sampling rate and the timestamp base frequency to determine whether it meets the preset synchronization threshold range. If it does, it is marked as a matching state; otherwise, it is marked as a mismatch state, and a timestamp matching state is generated. The synchronization parameter generation submodule generates reference parameters based on the timestamp matching status. If the timestamp is matched, it generates reference parameters based on the timestamp base frequency and the audio / video sampling rate. If the timestamp is mismatched, it recalibrates the correspondence between the timestamp base frequency and the audio / video sampling rate to generate timestamp synchronization parameters.

6. The E1 / IP video conferencing protocol conversion system according to claim 5, characterized in that: The buffer control module includes: The time synchronization calibration submodule obtains buffer timestamp data based on the timestamp synchronization parameters, aligns the device's local clock with the global clock in terms of time series, calculates the average timestamp deviation, performs incremental compensation on the local clock settings based on the average deviation, and generates a synchronization difference value. The fluctuation trend monitoring submodule calls the synchronization difference value to monitor the number of data packets occupied and the number of bytes transmitted by the interface within a unit time slot, calculates the moving average of the time slot occupancy rate and the rate of change of throughput respectively, extracts the fluctuation correlation characteristics of occupancy rate and throughput, and generates the fluctuation correlation degree. The dynamic balance determination submodule sets the time slot occupancy rate boundary and the throughput fluctuation tolerance range based on the synchronization difference value and the fluctuation correlation. It determines whether the current occupancy rate exceeds the boundary and the correlation is outside the tolerance range. If the conditions are met, it adjusts the buffer read / write rate ratio according to the deviation direction and generates a buffer level control command.

7. The E1 / IP video conferencing protocol conversion system according to claim 6, characterized in that: The specific formula for calculating the average timestamp deviation is as follows: in, This represents the average synchronization deviation between local and global time after adjustment and weighting, where N represents the number of timestamp pairs included in the deviation statistics. Represents the timestamp of the i-th local device clock. Represents the i-th global clock timestamp. Let represent the j-th network latency measurement value, M represent the number of network latency measurement samples, and γ represent the synchronization adjustment scaling factor, which is unit-independent.

8. The E1 / IP video conferencing protocol conversion system according to claim 6, characterized in that: The synchronization coordination module includes: The frame packet alignment submodule integrates the buffer level control command, the frame-to-packet alignment status identifier, the cross-protocol signaling mapping table, and the timestamp synchronization parameters, detects the position offset between the frame boundary marker and the packet start marker, extracts the current check bit sequence of the cyclic redundancy check code, calculates the difference between the offset and the preset packet alignment tolerance threshold, and generates the alignment check rate. The signaling timing control submodule calls the alignment check rate, extracts the timing priority flags of cross-protocol fields, performs linear interpolation compensation on the reference clock deviation value in timestamp synchronization, and compares the buffer level value with the preset level threshold to generate the synchronization control amount. The dual-stack collaborative generation submodule accumulates and counts the number of times the cyclic redundancy check error event is triggered based on the synchronization control amount, calculates the ratio of the clock timing deviation value to the upper limit of the synchronization tolerance, and combines the statistical value and the ratio according to the set ratio to generate dual-stack collaborative control instructions.

9. The E1 / IP video conferencing protocol conversion system according to claim 8, characterized in that: The specific formula for calculating the positional offset between the detection frame boundary marker and the packet start marker is as follows: Where, Δ′ pos This represents the position offset adjustment value, where n represents the total number of frames within the sampling window, and w i p represents the payload bit width of the i-th frame. i b represents the periodic frame identifier count within the i-th frame. i Indicates the starting bit position of the frame boundary marker for the i-th frame, k i This indicates the number of protocol layer mapping fields in the i-th frame.

10. An E1 / IP video conferencing protocol conversion device, comprising a memory and a processor, characterized in that, The memory stores a computer program, and the E1 / IP video conferencing protocol conversion device is equipped with the E1 / IP video conferencing protocol conversion system according to any one of claims 1-9.

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