The online monitor method of voice gatewaysTechnical field
The present invention relates to the technology of VOIP system, particularly to the monitoring system of VOIP system.
Background technology
Along with being widely used of ip voice (VOIP) system, monitor the call of VOIP user in real time, be increasingly necessary for the release mechanisms such as national security, public security and prison.Online monitor the user being often referred to through authorizing on the equipment such as voice gateways with monitor function, in real time between monitoring local user, the content of voice call between local user and IP user or IP user.
Mainly use the mode of digital signal processor (DigitalSignalProcessing, DSP) audio mixing to realize monitor function at present in VOIP voice gateways, but a lot of dsp chip itself does not support Three-Way Calling or conferencing function.The VOIP gateway using this dsp chip realizes monitor, need to be redirected to the rtp streaming of monitored side third party's (server), being decoded on the server, audio mixing and coding, be converted into the operation such as played file, its real-time cannot ensure.
G.711A restraining coding (being called for short G711A) is a kind of compression/decompression algorithm about pulse code that ITU-T (International Telecommunication Union) defines, and A rule compression algorithm can be used to carry out the encoding and decoding of speech data by most countries at present.
Summary of the invention
The purpose of the present invention is exactly to overcome to realize, in current VOIP voice gateways, the shortcoming that monitor function cannot ensure real-time, it is provided that a kind of online monitor method of voice gateways.
The present invention solves its technical problem, employed technical scheme comprise that, the online monitor method of voice gateways, it is characterised in that comprise the following steps:
Step 1. starts monitor function according to the instruction of monitoring side；
Step 2. system judges whether the coding mode needing that a-road-through monitored words to use is G711A, if then entering step 3, otherwise by Session Initiation Protocol, coding mode is revised as G711A；
The two-way rtp streaming of call is redirected to internal damping queue by step 3. system；
Step 4. system is decoded as pulse code modulation PCM data respectively to the two-way realtime transmission protocol RTP stream in internal buffer queue；
Two-way PCM data is used software audio mixing to synthesize a road PCM data by step 5. system；
PCM data after synthesis is converted to G711A and restrains encoding format data by step 6. system；
G711A rule encoding format data after conversion is sent to monitoring side by RTP data message by step 7. system.
Concrete, step 3 comprises the following steps:
Step 301. arranges the digital signal processor DSP of voice gateways and processes the packet sending and receiving direction with Fixed Time Interval in turn；
The packet sending and receiving direction in same for the DSP of voice gateways time interval is stored in a node by step 302. system, and this node is as audio mixing node；
Step 303. system redirects audio mixing node to internal damping queue.
Further, in step 301, described Fixed Time Interval is 20 milliseconds.
Concrete, step 4 comprises the following steps:
Step 401. system takes out the audio mixing node of redirection from internal damping queue, comprises two-way rtp streaming in this audio mixing node；
It is PCM data by byte code that G711A in the rtp streaming of each road is restrained coded data by step 402. system respectively.
Further, in step 402, described in be encoded to PCM data be to be encoded to the PCM data of 16.
Concrete, step 5 comprises the following steps:
The mode that two-way PCM data is used linear superposition to take average by step 501. system realizes software audio mixing, is synthesized a road PCM data.
Further, step 6 comprises the following steps:
PCM data is converted to G711A in the mode that each two byte conversion is G711A rule coding and restrains encoding format data by one road PCM data of synthesis by step 601. system.
Concrete, step 7 comprises the following steps:
The G711A obtained rule encoding format data is converted to RTP data message by step 701. system；
Step 702. system judges whether monitoring side is local user, if then entering step 703, otherwise enters step 704；
This RTP data message is directly sent to monitoring side by step 703. system；
This RTP data message is sent to monitoring side by IP mode by step 704. system.
Further, described local user refers to that monitoring side and monitored side are in same voice gateways.
The invention has the beneficial effects as follows, by the online monitor method of upper voice gateway, achieve monitoring in real time, and use the mode of software audio mixing, need not, on the DSP of VOIP voice gateways, there is mixer, also for the providing a great convenience property of use of monitoring service, monitoring personnel can monitor in this locality, it is also possible to is monitored by remote mode.
Accompanying drawing explanation
Fig. 1 is the structured flowchart of embodiment of the present invention monitoring system.
Fig. 2 is the flow chart of the online monitor method of voice gateways of the present invention.
Fig. 3 is the flow chart redirecting rtp streaming in the online monitor method of voice gateways of the present invention.
Fig. 4 is the flow chart of software audio mixing in the online monitor method of voice gateways of the present invention.
Fig. 5 is the flow chart of voice gateways of the present invention online monitor method repeating data.
Detailed description of the invention
Below in conjunction with embodiment and accompanying drawing, describe technical scheme in detail.
The flow chart of the online monitor method of voice gateways of the present invention sees Fig. 2.In the online monitor method of voice gateways of the present invention, first monitor function is started, then system judges whether the coding mode needing that a-road-through monitored words to use is G711A, otherwise coding mode is revised as G711A by Session Initiation Protocol, if then the two-way rtp streaming of call is redirected to internal damping queue by system, the two-way rtp streaming in the most internal buffer queue is decoded as PCM data respectively, and two-way PCM data employing software audio mixing is synthesized a road PCM data, again the PCM data after synthesis is converted to G711A and restrains encoding format data, finally the G711A rule encoding format data after conversion is sent to the broadcasting of the side of monitoring by RTP data message.
Embodiment
In the embodiment of the present invention, the structured flowchart of monitoring system sees Fig. 1.The monitoring system of the present embodiment is by the voice gateways 1 realizing monitor function, connecting the monitored side user A of voice gateways 1, the outside line user B connecting voice gateways 1 by IP network and the monitoring side user C realizing monitoring this locality to the user A in voice gateways 1 by E1/FXS/FX0 mode forms.VOIP gateway 1 is disposed monitor function, thus realizes the call of the side of monitoring user C monitoring users A and any outside line user C, or monitoring users A call of any local user with in voice gateways 1.It addition, monitoring side user C can realize remote monitoring by IP mode to the user A in voice gateways 1.
The online monitor method of voice gateways of the present embodiment, sees Fig. 2, and for the flow chart of the online monitor method of voice gateways in the embodiment of the present invention, its detailed process is as follows:
Step 1. starts monitor function according to the instruction of monitoring side；
Step 2. system judges whether the coding mode needing that a-road-through monitored words to use is G711A, if then entering step 3, otherwise by Session Initiation Protocol, coding mode is revised as G711A；
Here, computational efficiency when audio mixing effect and audio mixing can be greatly improved by the amendment of coding.
The two-way rtp streaming of call is redirected to internal damping queue by step 3. system；
See Fig. 3, for the online monitor method of voice gateways in the embodiment of the present invention redirects the flow chart of rtp streaming.Step 3 comprises the following steps: the DSP first arranging voice gateways processes the packet sending and receiving direction in turn with Fixed Time Interval, this Fixed Time Interval is 20 milliseconds, again the packet sending and receiving direction in same for the DSP of voice gateways time interval is stored in a node, this node, as audio mixing node, finally redirects audio mixing node to internal damping queue.Here the two-way RTP owing to redirecting during audio mixing must be to synchronize, the amount of calculation brought in order to avoid simultaneously operating and calculating time, use the mode of interrupt processing, the DSP of gateway (i.e. DSP is every 20 milliseconds of operations once read and write) at regular intervals processes the packet sending and receiving direction in turn, therefore the packet of both direction can be stored in a node, it is not necessary to extra simultaneously operating；And in prior art, before audio mixing starts, owing to needs carry out pretreatment to data, it is therefore necessary to the data source of audio mixing is buffered, simultaneously mutual in order to ensure the both call sides monitored order, the data of both direction must keep consistent on timestamp.If the method using software is come data message according to timestamp ordering, it will be the most complicated for processing and effect is uncertain very well.The present invention makes full use of the DSP in gateway and processes the feature of the packet sending and receiving direction the most in turn, in same time interval, the packet of both direction stores a node；This node is as audio mixing node, the concordance that thus the effective both call sides ensureing to monitor is mutual.Then redirection audio mixing node is to internal damping queue, for follow-up stereo process.
Step 4. system is decoded as PCM data respectively to the two-way rtp streaming in internal buffer queue；
Here the first system of specifically comprising the following steps that of step 4 takes out the audio mixing node of redirection from internal damping queue, this audio mixing node comprises two-way rtp streaming, the G711A in the rtp streaming of the most each road is restrained coded data and is encoded to the PCM data of 16 by byte (G711A encodes by 8 expressions).
Two-way PCM data is used software audio mixing to synthesize a road PCM data by step 5. system；
In the embodiment of the present invention, in the online monitor method of voice gateways, the flow chart of software audio mixing sees Fig. 4.Two square tubes the most common due to the call of monitored side are talked about, Three-Way Calling, or MPTY, all comprise only sending direction and receive the two-way rtp streaming in direction.According to this feature of only two-way rtp streaming, use linear superposition to take the algorithm of average, monitor effect and be entirely capable of meeting the quality of monitoring.Therefore the mode that two-way PCM data is used linear superposition to take average by system realizes software audio mixing, is synthesized a road PCM data, and the PCM data of such as recipient is B, and the PCM data of sender is A, then the PCM data after its synthesis is (A+B)/2.
PCM data after synthesis is converted to G711A and restrains encoding format data by step 6. system；
Here, PCM data is converted to G711A in the mode that each two byte conversion is G711A rule coding and restrains encoding format data by a road PCM data of synthesis by its system.
G711A rule encoding format data after conversion is sent to the broadcasting of the side of monitoring by RTP data message by step 7. system；
In the embodiment of the present invention, the flow chart of voice gateways online monitor method repeating data sees Fig. 5.Here, step 7 comprises the following steps:
The G711A obtained rule encoding format data is converted to RTP data message by step 701. system；
Step 702. system judges whether monitoring side is local user, if then entering step 703, otherwise enters step 704；
This RTP data message is directly sent to monitoring side by step 703. system；
This RTP data message is sent to monitoring side by IP mode by step 704. system.
Wherein, local user refers to that monitoring side and monitored side are in same voice gateways.Otherwise local user is then long-distance user, and long-distance user refers to that monitoring side is connected by IP with monitored side.