CN104539593A - H.245 message analysis method - Google Patents
H.245 message analysis method Download PDFInfo
- Publication number
- CN104539593A CN104539593A CN201410783865.XA CN201410783865A CN104539593A CN 104539593 A CN104539593 A CN 104539593A CN 201410783865 A CN201410783865 A CN 201410783865A CN 104539593 A CN104539593 A CN 104539593A
- Authority
- CN
- China
- Prior art keywords
- message
- bit
- decoding
- decoding functions
- signaling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
The invention relates to an H.245 message analysis method. The H.245 message analysis method includes the first step of building of an H.245 decoding signaling tree; the second step of definition and mapping of a message; the third step of decoding, wherein a corresponding decoding function is written for each message structure, an message decoding function corresponding to a decoding function base is called, and the decoding work is finished; the fourth step of extraction of message bits; the fifth step of data filling of the H.245 signaling tree, wherein for each control message, the own decoding function is called to feed back an extracted bit value, and the decoding function fills the corresponding value to a node corresponding to the message; the sixth step of outputting of a decoding result, wherein an output display module is called, the signaling tree of the message is traversed, the data values filling to each layer of nodes are read layer by layer and output visually, and the correctness of decoding is verified. The H.245 message analysis method can provide key parameters and function interfaces for multiplexing of video telephone service data frames.
Description
(1), technical field: the present invention relates to a kind of message resolution method, particularly relate to one H.245 message resolution method.
(2), background technology: H.245 agreement (Control protocol for multimedia communication) be H.323 in protocol suite for agreement that media channel controls, mainly complete the foundation of each logical channel in multimedia communication, maintenance and release, specifically comprise the controlling functions such as capability negotiation of the opening and closing of logical channel, setting parameter, receiving-transmitting sides, it also will complete the cooperation controlling functions of logic channel in multipoint conference calling simultaneously.H.245 define the syntax and semantics of interaction message in communication process, be described the reciprocal process of primary message, its definition to message syntax adopts a kind of successively nested message structure.
H.245 in OSI framework, application layer protocol is belonged to, its function determines H.245 message will use very complicated signaling, therefore ASN ASN.1 is used to define type and the form of signaling, the Packet encoding rules (PER, Packet Encoding Rules) of non-alignment is adopted to represent.Because PER bitwise encodes, and do not fill between each information unit, therefore implement more complicated.
(3), summary of the invention:
The technical problem to be solved in the present invention is: provide one H.245 message resolution method, and the method can be can
The multiplexing of phonovision business data frame provides key parameter sum functions interface.
Technical scheme of the present invention:
One is message resolution method H.245, containing the following step:
The structure of step 1, H.245 Xie Maxinlingshu:
H.245 the top layer of message is the control message (Multimedia System Control Message) of multimedia system, and the control message of multimedia system contains Four types: recipient need respond and the request message of replying (Request Message), the response message (Response Message) of acknowledges requests message (Request Message), recipient need respond but do not respond without the need to the command messages (Command Message) of response, recipient and without the need to the Indication message (Indication Message) of response; The message of this Four types is the first order type of message of H.245 control protocol, and every type message structure contains again N seed type of message, sets as next straton, by that analogy, nested according to layer, final formation H.245 overall signaling message; According to the level nested structure of H.245 overall signaling message, its whole protocol message is defined as a tree-like structure type; For H.245 signaling tree structure, a control message unit may have a lot of paths to arrive in tree structure, but for bit stream to be decoded, has at every turn and only have a paths effective, can arrive.Obtain the information of bottom layer node, the node on upper strata must be covered, so when decoding, the path likely occurred must be considered, the correctness of guarantee decoding.
The definition of step 2, message, mapping:
The H.245 data type described with ASN.1 PER definition and corresponding message structure are defined, are mapped as the data structure file of program language description, this is the basis of decoding; Structure after mapping has enough information and carries out encoding or have enough territories and deposit decoded data; The function mapped often kind of data type that ASN.1 describes all is mapped in the decoding functions of its correspondence to go, and these decoding functions call the decoding function that the corresponding decoding functions of lower floor realizes message again.
Step 3, decoding:
After data type and message structure are mapped to program file, be next exactly utilize decoding functions storehouse to decode, decoding functions storehouse is the core of H.245 resolving; Foundation H.245 signaling table structure, must write corresponding decoding functions to each message structure; Decoding functions due to H.245 message comprises calling for basic data type and compound data structure, so for basic data type and compound data structure, also needs corresponding decoding functions storehouse; Decoding functions part provides calling interface with api interface to other module, also docking port module is transparent for itself, the decoding functions of message must determine the bit number acquired by it, and initialization buffering area byte and bit two pointer positions, pass to bit extraction function; Receive the H.245 data flow after ASN.1 PER encodes by interface section, then call the source codec function that decoding functions storehouse is corresponding, complete decoding effort, and result is sent by interface section;
Step 4, message bit are extracted:
For H.245 signaling tree, even if required unit is essential unit and bit number is fixed, still need by the node going to information place according to tree structure of bit.For this reason, in parsing module, design the function that is taken out any bit neatly from bit stream, this function accepts calling of decoding functions, extracts corresponding information flow bit, and numerical value is returned to decoding functions; Function self returns the figure place of got bit, to verify the correctness extracting bit quantity, and adjusts the position of two pointer according to got number of bits; Like this, even if information layer layer is H.245 nested, also can by repeatedly calling the extraction of this function realization to information unit.
The data stuffing of step 5, H.245 signaling tree:
For every bar control information, return got bit value by the decoding functions calling oneself, the numerical value of correspondence is filled on node corresponding to this message by decoding functions, and all the other nodes at the corresponding levels are not filled, and are worth for sky;
Step 6, decoded result export:
After one H.245 signaling resolution, message corresponding signaling tree fill complete, call output display module, the signaling tree of this message is traveled through, read the data value that each node layer is filled step by step, and carry out visual output, the correctness of checking decoding.
H.245 data type in step 2 contains fundamental type and compound type.
The position of two pointer is moved after referring to according to the position of the two pointer of got number of bits adjustment in step 4.
Before calling decoding functions storehouse, must initialization operation be performed, complete the setting to 0 of two pointer, H.245
Signaling is set each node and is emptied these operations;
The decoding functions of message must determine the bit number acquired by it, and initialization buffering area byte and bit two pointer positions, pass to bit extraction function;
After bit extraction function obtains required bit, content is returned to corresponding decoding functions, self return the figure place of got bit, with proving correctness, and adjust the position of two pointer according to got number of bits; Two pointer is crucial, can not location revision easily;
In C language, the not data structure of corresponding stored bit (being less than 8), therefore, the read method of bit value is: the byte comprising bit to be read (n position) taken out from buffering area, first carry out move to left (being determined by bit pointer), carry out left-justify, then carry out Right Aligns, by the bit position clear 0 before got bit, complete actual bit position and read;
The organization definition of every bar H.245 message is exactly the definition of composite data type, and the decoding functions of each message finally needs the decoding functions calling fundamental type, return value is inserted signaling tree corresponding node;
For the parameter that number in the definition of H.245 message is indefinite, according to number of parameters in real messages number, different memory allocation schemes is provided; If number of parameters is less, then use static storage; If Static-state Space is not enough to deposit parameter, then dynamically apply for space.This method can adapt to the various situations that protocol definition goes out, again can in most of source codec process guaranteed efficiency.
Beneficial effect of the present invention:
1, the present invention first proposed on the Packet encoding rules PER basis that further investigation ASN.l describes
PER tree-shaped decode structures, and design achieves the PER decoder that can be used for communication system; The present invention is directed to the decoding functions that in signaling tree, message composition corresponding to each node is corresponding, nested layer by layer; When to source codec, in depth-first search mode, signaling tree is traveled through, the decoding functions of message calls decoding functions corresponding to the fundamental sum compound type data that comprise, extract corresponding bit value, and data value is successively filled on node corresponding to message signaling tree, until leafy node terminates.The present invention carries out Decoding Analysis to the message structure after ASN.1 PER encodes, and obtains the particular content of control message, for the multiplexing of visual telephone service Frame provides key parameter sum functions interface.
(4), accompanying drawing illustrates:
Fig. 1 is H.245 signaling tree structure schematic diagram;
Fig. 2 be H.245 data type and message structure to the mapping schematic diagram of C data structure file;
Fig. 3 is decoding program flow chart.
(5), embodiment:
H.245 message resolution method contains the following step:
The structure of step 1, H.245 Xie Maxinlingshu:
H.245 the top layer of message is the control message (Multimedia System Control Message) of multimedia system, and the control message of multimedia system contains Four types: recipient need respond and the request message of replying (Request Message), the response message (Response Message) of acknowledges requests message (Request Message), recipient need respond but do not respond without the need to the command messages (Command Message) of response, recipient and without the need to the Indication message (Indication Message) of response; The message of this Four types is the first order type of message of H.245 control protocol, and every type message structure contains again N seed type of message, sets as next straton, by that analogy, nested according to layer, final formation H.245 overall signaling message; According to the level nested structure of H.245 overall signaling message, its whole protocol message is defined as a tree-like structure type (as shown in Figure 1); For H.245 signaling tree structure, a control message unit may have a lot of paths to arrive in tree structure, but for bit stream to be decoded, has at every turn and only have a paths effective, can arrive.Obtain the information of bottom layer node, the node on upper strata must be covered, so when decoding, the path likely occurred must be considered, the correctness of guarantee decoding.
The definition of step 2, message, mapping:
The H.245 data type described with ASN.1 PER definition and corresponding message structure are defined, are mapped as the data structure file (as shown in Figure 2) of program language description, this is the basis of decoding; Structure after mapping has enough information and carries out encoding or have enough territories and deposit decoded data; The function mapped often kind of data type that ASN.1 describes all is mapped in the decoding functions of its correspondence to go, and these decoding functions call the decoding function that the corresponding decoding functions of lower floor realizes message again.
Step 3, decoding:
After data type and message structure are mapped to program file, be next exactly utilize decoding functions storehouse to carry out decode (as shown in Figure 3), decoding functions storehouse is the core of H.245 resolving; Foundation H.245 signaling table structure, must write corresponding decoding functions to each message structure; Decoding functions due to H.245 message comprises calling for basic data type and compound data structure, so for basic data type and compound data structure, also needs corresponding decoding functions storehouse; Decoding functions part provides calling interface with api interface to other module, also docking port module is transparent for itself, the decoding functions of message must determine the bit number acquired by it, and initialization buffering area byte and bit two pointer positions, pass to bit extraction function; Receive the H.245 data flow after ASN.1 PER encodes by interface section, then call the source codec function that decoding functions storehouse is corresponding, complete decoding effort, and result is sent by interface section;
Step 4, message bit are extracted:
For H.245 signaling tree, even if required unit is essential unit and bit number is fixed, still need by the node going to information place according to tree structure of bit.For this reason, in parsing module, design the function that is taken out any bit neatly from bit stream, this function accepts calling of decoding functions, extracts corresponding information flow bit, and numerical value is returned to decoding functions; Function self returns the figure place of got bit, to verify the correctness extracting bit quantity, and adjusts the position of two pointer according to got number of bits; Like this, even if information layer layer is H.245 nested, also can by repeatedly calling the extraction of this function realization to information unit.
The data stuffing of step 5, H.245 signaling tree:
For every bar control information, return got bit value by the decoding functions calling oneself, the numerical value of correspondence is filled on node corresponding to this message by decoding functions, and all the other nodes at the corresponding levels are not filled, and are worth for sky;
Step 6, decoded result export:
After one H.245 signaling resolution, message corresponding signaling tree fill complete, call output display module, the signaling tree of this message is traveled through, read the data value that each node layer is filled step by step, and carry out visual output, the correctness of checking decoding.
H.245 data type in step 2 contains fundamental type and compound type.
The position of two pointer is moved after referring to according to the position of the two pointer of got number of bits adjustment in step 4.
Before calling decoding functions storehouse, must initialization operation be performed, complete the setting to 0 of two pointer, H.245
Signaling is set each node and is emptied these operations;
The decoding functions of message must determine the bit number acquired by it, and initialization buffering area byte and bit two pointer positions, pass to bit extraction function;
After bit extraction function obtains required bit, content is returned to corresponding decoding functions, self return the figure place of got bit, with proving correctness, and adjust the position of two pointer according to got number of bits; Two pointer is crucial, can not location revision easily;
In C language, the not data structure of corresponding stored bit (being less than 8), therefore, the read method of bit value is: the byte comprising bit to be read (n position) taken out from buffering area, first carry out move to left (being determined by bit pointer), carry out left-justify, then carry out Right Aligns, by the bit position clear 0 before got bit, complete actual bit position and read;
The organization definition of every bar H.245 message is exactly the definition of composite data type, and the decoding functions of each message finally needs the decoding functions calling fundamental type, return value is inserted signaling tree corresponding node;
For the parameter that number in the definition of H.245 message is indefinite, according to number of parameters in real messages number, different memory allocation schemes is provided; If number of parameters is less, then use static storage; If Static-state Space is not enough to deposit parameter, then dynamically apply for space.This method can adapt to the various situations that protocol definition goes out, again can in most of source codec process guaranteed efficiency.
Claims (4)
1. a H.245 message resolution method, is characterized in that: containing the following step:
The structure of step 1, H.245 Xie Maxinlingshu:
H.245 the top layer of message is the control message of multimedia system, and the control message of multimedia system contains Four types: recipient need respond and the response message of the request message of replying, acknowledges requests message, recipient need respond but do not respond without the need to the command messages of response, recipient and without the need to the Indication message of response; The message of this Four types is the first order type of message of H.245 control protocol, and every type message structure contains again N seed type of message, sets as next straton, final formation H.245 overall signaling message; According to the level nested structure of H.245 overall signaling message, its whole protocol message is defined as a tree-like structure type;
The definition of step 2, message, mapping:
The H.245 data type described with ASN.1 PER definition and corresponding message structure are defined, are mapped as the data structure file of program language description; Structure after mapping has enough information and carries out encoding or have enough territories and deposit decoded data;
Step 3, decoding:
Corresponding decoding functions is write to each message structure; Decoding functions due to H.245 message comprises calling for basic data type and compound data structure, so for basic data type and compound data structure, also needs corresponding decoding functions storehouse; Decoding functions part provides calling interface with api interface to other module, also docking port module is transparent for itself, the decoding functions of message must determine the bit number acquired by it, and initialization buffering area byte and bit two pointer positions, pass to bit extraction function; Receive the H.245 data flow after ASN.1 PER encodes by interface section, then call the source codec function that decoding functions storehouse is corresponding, complete decoding effort, and result is sent by interface section;
Step 4, message bit are extracted:
In parsing module, design the function that is taken out any bit neatly from bit stream, this function accepts calling of decoding functions, extracts corresponding information flow bit, and numerical value is returned to decoding functions; Function self returns the figure place of got bit, to verify the correctness extracting bit quantity, and adjusts the position of two pointer according to got number of bits;
The data stuffing of step 5, H.245 signaling tree:
For every bar control information, return got bit value by the decoding functions calling oneself, the numerical value of correspondence is filled on node corresponding to this message by decoding functions, and all the other nodes at the corresponding levels are not filled, and are worth for sky;
Step 6, decoded result export:
After one H.245 signaling resolution, message corresponding signaling tree fill complete, call output display module, the signaling tree of this message is traveled through, read the data value that each node layer is filled step by step, and carry out visual output, the correctness of checking decoding.
2. H.245 message resolution method according to claim 1, is characterized in that: the H.245 data type in described step 2 contains fundamental type and compound type.
3. H.245 message resolution method according to claim 1, is characterized in that: the position moving two pointer after referring to according to the position of the two pointer of got number of bits adjustment in described step 4.
4. H.245 message resolution method according to claim 1, is characterized in that: before calling decoding functions storehouse, must perform initialization operation, completes the setting to 0 of two pointer, H.245 signaling and sets each node and empty these operations;
The decoding functions of message must determine the bit number acquired by it, and initialization buffering area byte and bit two pointer positions, pass to bit extraction function;
After bit extraction function obtains required bit, content is returned to corresponding decoding functions, self return the figure place of got bit, with proving correctness, and adjust the position of two pointer according to got number of bits;
The read method of bit value is: the byte comprising bit to be read taken out from buffering area, first move to left, and carries out left-justify, then carries out Right Aligns, by the bit position clear 0 before got bit, completes actual bit position and reads;
The organization definition of every bar H.245 message is exactly the definition of composite data type, and the decoding functions of each message finally needs the decoding functions calling fundamental type, return value is inserted signaling tree corresponding node;
For the parameter that number in the definition of H.245 message is indefinite, according to number of parameters in real messages number, different memory allocation schemes is provided; If number of parameters is less, then use static storage; If Static-state Space is not enough to deposit parameter, then dynamically apply for space.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410783865.XA CN104539593B (en) | 2014-12-18 | 2014-12-18 | H.245 message resolution method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410783865.XA CN104539593B (en) | 2014-12-18 | 2014-12-18 | H.245 message resolution method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104539593A true CN104539593A (en) | 2015-04-22 |
| CN104539593B CN104539593B (en) | 2017-06-23 |
Family
ID=52855062
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410783865.XA Active CN104539593B (en) | 2014-12-18 | 2014-12-18 | H.245 message resolution method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104539593B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106899377A (en) * | 2015-12-17 | 2017-06-27 | 联芯科技有限公司 | A kind of channel decoding method and device |
| CN113742294A (en) * | 2021-08-23 | 2021-12-03 | 宜通世纪科技股份有限公司 | Method, system, device and medium for decoding ASN.1-PER signaling message |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6335927B1 (en) * | 1996-11-18 | 2002-01-01 | Mci Communications Corporation | System and method for providing requested quality of service in a hybrid network |
| CN1882116A (en) * | 2005-08-11 | 2006-12-20 | 华为技术有限公司 | Mobile switching centre built in video gateway and method for realizing multimedia interconnection |
| CN1910926A (en) * | 2004-01-21 | 2007-02-07 | 达丽星网络有限公司 | Method and apparatus for handling video communication errors |
| US20090116477A1 (en) * | 2005-10-21 | 2009-05-07 | Siemens Aktiengesellschaft | Signaling Referring to Setup of H.324 Video Telephone Between Media Gateway and Controller |
| CN101494696A (en) * | 2002-12-12 | 2009-07-29 | 达丽星网络有限公司 | Methods and system for fast session establishment between equipment using H.324 and related telecommunications protocols |
| CN101640784A (en) * | 2008-07-28 | 2010-02-03 | 上海领世通信技术发展有限公司 | Device and method for controlling multi-image compounding in video conference system |
-
2014
- 2014-12-18 CN CN201410783865.XA patent/CN104539593B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6335927B1 (en) * | 1996-11-18 | 2002-01-01 | Mci Communications Corporation | System and method for providing requested quality of service in a hybrid network |
| CN101494696A (en) * | 2002-12-12 | 2009-07-29 | 达丽星网络有限公司 | Methods and system for fast session establishment between equipment using H.324 and related telecommunications protocols |
| CN1910926A (en) * | 2004-01-21 | 2007-02-07 | 达丽星网络有限公司 | Method and apparatus for handling video communication errors |
| CN1882116A (en) * | 2005-08-11 | 2006-12-20 | 华为技术有限公司 | Mobile switching centre built in video gateway and method for realizing multimedia interconnection |
| US20090116477A1 (en) * | 2005-10-21 | 2009-05-07 | Siemens Aktiengesellschaft | Signaling Referring to Setup of H.324 Video Telephone Between Media Gateway and Controller |
| CN101640784A (en) * | 2008-07-28 | 2010-02-03 | 上海领世通信技术发展有限公司 | Device and method for controlling multi-image compounding in video conference system |
Non-Patent Citations (4)
| Title |
|---|
| ITU-T: "H.246 Control Protocol For Multimedia Communication", 《ITU-T RECOMMENDATION》 * |
| LV QIAN,HUANG BENXIONG,WANG FURONG: "The mechanism of ASN.1 encoding and decoding implementation in network protocols", 《INFORMATION TECHNOLOGY: CODING AND COMPUTING》 * |
| 冯雁; 彭宇; 刘芳: "SIP-H323信令转换网关中H.245隧道机制的实现方案", 《通信技术》 * |
| 申崇江,张文军,石峻: "可视电话系统中多媒体通信控制协议H1245的实现", 《红外与激光工程》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106899377A (en) * | 2015-12-17 | 2017-06-27 | 联芯科技有限公司 | A kind of channel decoding method and device |
| CN106899377B (en) * | 2015-12-17 | 2019-07-12 | 辰芯科技有限公司 | A kind of channel decoding method and device |
| CN113742294A (en) * | 2021-08-23 | 2021-12-03 | 宜通世纪科技股份有限公司 | Method, system, device and medium for decoding ASN.1-PER signaling message |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104539593B (en) | 2017-06-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11200701B2 (en) | Method and apparatus for storage and signaling of static point cloud data | |
| US11581022B2 (en) | Method and apparatus for storage and signaling of compressed point clouds | |
| JP6233984B2 (en) | Virtual reference decoder for multiview video coding | |
| US11595670B2 (en) | Method and apparatus for storage and signaling of sub-sample entry descriptions | |
| AU2018271391A1 (en) | Image processing device and method | |
| CN105159928B (en) | A kind of JSON data conversion at model data method and system | |
| JP2017130966A (en) | Media content decoding method in multimedia system | |
| RU2009142429A (en) | CODING SYSTEMS | |
| CN105900445B (en) | The method and apparatus of steady live operation for dynamic self-adapting stream transmission | |
| CN110447234A (en) | Section type as separator and addressable resource identifier | |
| CN109684097B (en) | CMSP-based JSON data analysis and storage method | |
| WO2015096540A1 (en) | Bitstream generation and processing methods and devices and system | |
| CN108111865A (en) | JCTVC-L0226：VPS and VPS_EXTENSION updates | |
| CN105451061A (en) | Screen sharing method and device | |
| CN104539593A (en) | H.245 message analysis method | |
| CN105491387A (en) | H264 hardware coding system based on three platforms of Intel, AMD and Nvidia | |
| CN115668937A (en) | Methods, apparatus and articles of manufacture to generate packed video frames for volumetric and immersive video bitstreams | |
| CN101924666A (en) | Decoding realization method and system of signaling tracking | |
| CN104469400A (en) | Image data compression method based on RFB protocol | |
| CN104935923B (en) | Coding method and system, signal decoding method and system | |
| CN109257571A (en) | A kind of system and method that real-time video is shown simultaneously with geographical location information | |
| CN105263021A (en) | UVD-based HEVC video decoding method | |
| KR20230173096A (en) | Anchoring scene descriptions to user experiences for streaming immersive media content | |
| CN104320644B (en) | A kind of decoding method of depth information, system and device | |
| CN104462220B (en) | Web page screen-cutting and coding and transmission method and device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |