JP2002111777A - Multimedia communication protocol converter - Google Patents

Abstract

(57) [Problem] To provide a multimedia communication protocol conversion device capable of suppressing deterioration of audio quality and image quality and processing delay and enabling communication between multimedia communication terminals having different communication protocols. To provide. A multimedia communication protocol conversion device according to the present invention includes two multimedia communication terminals having different communication protocols via communication lines.
When communication is performed between the two multimedia communication terminals 05, the audio code and the image code are matched so that the two multimedia communication terminals 204 and 205 can communicate with each other using a common encoding rule or encoding format.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, for example, in a wireless communication system or a wired communication system, matches a voice code and an image code at the time of mutual communication with a wireless terminal or a wired terminal using different multimedia communication systems. It is about the method.

[0002]

2. Description of the Related Art Conventionally, when two terminals having different communication protocols are connected, two terminals having the same communication protocol as each terminal are connected in cascade to convert a communication protocol and a voice code and an image code. By doing so, communication was possible. There is also a method of matching voice codes at the time of communication between terminals in a wireless communication system. For example, there is Japanese Patent Application Laid-Open No. 6-6295.

FIG. 2 shows a multimedia communication terminal 103,
FIG. 1 shows a system configuration diagram of a conventional method for performing communication protocol conversion by cascade-connecting 104. FIG. 2 shows a multimedia communication terminal 101 connected to one communication network, a multimedia communication terminal 102 connected to the other communication network, and a protocol conversion having the same communication protocol as the multimedia communication terminals 101 and 102, respectively. 1 shows multimedia communication terminals 103 and 104 for use. Analog audio data and analog image data decoded by the multimedia communication terminals 103 and 104 are transmitted and received between the multimedia communication terminals 103 and 104 for protocol conversion.

[0004]

However, in the above-mentioned conventional protocol conversion method, the audio code and the image code are always returned to the analog signal by the cascade-connected audio codec and image codec. Processing delay due to decoding and encoding occurs. Further, regarding the method of matching the voice code at the time of communication between terminals in the wireless communication system, voice code,
It cannot be applied to multimedia communication in which image codes and control signals are multiplexed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and suppresses deterioration of voice quality and image quality and processing delay, and enables communication between multimedia communication terminals having different communication protocols. The present invention provides a multimedia communication protocol conversion device which enables the following.

[0006]

According to the present invention, there is provided a multimedia communication protocol conversion apparatus comprising: a line interface unit for communicating with one multimedia communication terminal; and a multimedia communication data received by the one line interface unit. A first codec unit that decodes and encodes each communication data obtained by separating the communication data from each other, and transmits multimedia communication data obtained by multiplexing communication data from the first codec unit to the other multimedia communication terminal. And the other line interface unit, to determine the protocol of the other multimedia communication terminal, select a code that enables communication from the one multimedia communication terminal to the other multimedia communication terminal, The first and second multimedia communication terminals perform encoding of a first codec unit. And performs the communication.

Therefore, the multimedia communication protocol conversion apparatus converts the audio code and the image code according to the multiplexing system and the communication control system of the different multimedia communication protocols to match the audio code and the image code, and Even if communication protocols are different between communication terminals, it is possible to perform communication while suppressing deterioration of communication quality and processing delay.

The multimedia communication protocol converter of the present invention decodes and encodes each communication data obtained by separating the multimedia communication data received from the other multimedia communication terminal by the other line interface unit. A second codec unit, which determines a protocol of the one multimedia communication terminal, selects a code enabling communication with the one multimedia communication terminal, and performs coding of the second codec unit. To perform mutual communication between the one and the other multimedia communication terminals.

Therefore, the multimedia communication protocol conversion device converts the audio code and the image code according to the multiplexing system and the communication control system of the different multimedia communication protocols to match the audio code and the image code, and Even if communication protocols differ between communication terminals, mutual communication can be performed while suppressing deterioration of communication quality and processing delay.

Further, at least one of the first codec unit and the second codec unit of the multimedia communication protocol converter of the present invention performs decoding into a digital image frame and encoding from a digital image frame. It is.

Accordingly, the multimedia communication protocol converter has an effect of eliminating image quality deterioration due to DA conversion and AD conversion of an image by decoding into a digital image frame and encoding from the digital image frame. Even if communication protocols are different between terminals, it is possible to perform communication while suppressing deterioration of communication quality and processing delay.

Further, at least one of the first codec unit and the second codec unit of the multimedia communication protocol converter of the present invention performs decoding into digital voice and encoding from digital voice. is there.

Therefore, this multimedia communication protocol conversion apparatus performs decoding to digital audio and encoding from digital audio without decoding audio data into analog audio and encoding from analog audio.
It has the function of eliminating sound quality deterioration due to audio DA conversion / AD conversion, and enables communication with reduced communication quality and reduced processing delay even if the communication protocol differs between multimedia communication terminals.

Further, at least one of the first codec unit and the second codec unit of the multimedia communication protocol conversion apparatus according to the present invention is characterized in that the digital image frame format of the digital image frame is decoded. This is to match the format of the frame.

Therefore, the multimedia communication protocol conversion apparatus has an effect of eliminating image quality deterioration due to image format conversion by matching the format of the digital image frame to be encoded with the format of the composite digital image frame. Even if the communication protocol is different between the multimedia communication terminals, it is possible to perform the communication while suppressing the deterioration of the communication quality and the processing delay.

Further, at least one of the first codec unit and the second codec unit of the multimedia communication protocol converter of the present invention is separated when the coding rule of the image can be made to match the decoding rule. , Does not perform decoding and encoding in its own device.

Therefore, this multimedia communication protocol conversion device has an effect of extremely effectively eliminating image quality degradation by disconnecting the codec when the coding rule of the image can be matched with the decoding side. Even if communication protocols are different between media communication terminals, it is possible to perform communication while suppressing deterioration of communication quality and processing delay.

Further, the multimedia communication protocol conversion device of the present invention separates at least one of the first codec unit and the second codec unit when a speech coding rule and a decoding rule can be matched. It does not perform decoding and encoding in its own device.

Therefore, the multimedia communication protocol conversion device has an effect of extremely effectively eliminating sound quality deterioration by disconnecting the codec when the coding rule of the voice can be matched with the decoding side. Even if communication protocols are different between media communication terminals, it is possible to perform communication while suppressing deterioration of communication quality and processing delay.

Further, the multimedia communication protocol conversion device of the present invention limits the image receiving capability for notifying at least one of the one codec unit and the other multimedia communication terminal to a predetermined capability.

Therefore, the multimedia communication protocol conversion device intentionally limits the image receiving capability of notifying the multimedia communication terminal to one and the other, and converts the format of the digital image frame to be decoded to the format of the encoded digital image frame. By matching the image frame format and the image coding rule with the decoding side, it has the effect of eliminating image quality degradation extremely effectively, and the communication protocol between multimedia communication terminals Even if they differ, it is possible to perform communication while suppressing deterioration of communication quality and processing delay.

Further, the multimedia communication protocol conversion device of the present invention limits the voice receiving capability for notifying at least one of the one multimedia communication terminal and the other multimedia communication terminal to a predetermined capability. .

Therefore, this multimedia communication protocol conversion device intentionally limits the voice receiving capability for notifying one and the other multimedia communication terminals, and makes the coding rule of the voice coincide with the decoding side. It has an effect of extremely effectively eliminating sound quality deterioration, and enables communication in which deterioration of communication quality and processing delay are suppressed even if communication protocols differ between multimedia communication terminals.

Further, the multimedia communication protocol converter of the present invention controls selection of a digital image frame format and a transmission coding rule for at least one of the one multimedia communication terminal and the other multimedia communication terminal. Is what you do.

Therefore, the multimedia communication protocol converter controls the format of the digital image frame and the selection of the transmission coding rule for one and the other multimedia communication terminals, and converts the format of the digital image frame to be decoded. It has the function of eliminating image quality degradation extremely effectively by matching the format of the digital image frame to be encoded and the encoding rule of the image with the decoding side. Even if communication protocols are different between terminals, it is possible to perform communication while suppressing deterioration of communication quality and processing delay.

Further, the multimedia communication protocol converter of the present invention controls the selection of a transmission coding rule for at least one of the one multimedia communication terminal and the other multimedia communication terminal.

Therefore, the multimedia communication protocol converter controls the transmission coding rule for one of the multimedia communication terminals and the other multimedia communication terminal to match the coding rule of the speech with the decoding side. It has an effect of extremely effectively eliminating sound quality deterioration, and enables mutual communication in which deterioration in communication quality and processing delay are suppressed even if communication protocols differ between multimedia communication terminals.

Further, the multimedia communication protocol conversion apparatus of the present invention is capable of receiving a loopback command of signal control information from the one multimedia communication terminal or the other multimedia communication terminal, If the loopback command corresponding to the protocol of the conversion destination is present, the command is converted and transmitted to the one or other multimedia communication terminal on the opposite side of the command receiving side without performing the backing.

Therefore, the multimedia communication protocol conversion device does not execute the loopback in its own device even if it receives the signal control information loopback command, and the loopback command corresponding to the conversion destination protocol is not transmitted. If there is, the function of simplifying the device and the function of appropriately maintaining the state transition of the system by converting it and transmitting it. Enables communication with reduced delay.

The multimedia communication protocol converter of the present invention, when continuously receiving the loopback command from the one multimedia communication terminal or the other multimedia communication terminal, converts the converted loopback command. And sends the command to the one multimedia communication terminal or the other multimedia communication terminal on the opposite side of the command receiving side.

Therefore, this multimedia communication protocol converter improves the transmission speed required for signal control by thinning out the converted loopback command and transmitting it when the loopback command is continuously received. In addition, the present invention has an effect of improving image quality and sound quality by reducing the amount of signal control processing, and enables communication in which deterioration of communication quality and processing delay are suppressed even if communication protocols differ between multimedia communication terminals.

Further, the multimedia communication protocol conversion device of the present invention updates the screen in its own device even if it receives a signal control information screen update request from the one multimedia communication terminal or the other multimedia communication terminal. Instead, the screen update request in the protocol of the conversion destination is transmitted to the one multimedia communication terminal or the other multimedia communication terminal on the side opposite to the screen update request receiving side.

Therefore, the multimedia communication protocol converter does not execute the screen update in its own device even when receiving the screen update request of the signal control information and transmits the screen update request in the conversion destination protocol, It has the effect of simplifying the device, and enables communication with reduced communication quality and reduced processing delay even if the communication protocol differs between multimedia communication terminals.

Further, the multimedia communication protocol converter of the present invention, when receiving a screen update request of signal control information from the one multimedia communication terminal or the other multimedia communication terminal, updates the screen in its own device. And transmitting the screen update request in the protocol of the conversion destination to the one multimedia communication terminal or the other multimedia communication terminal on the side opposite to the screen update request receiving side.

Therefore, the multimedia communication protocol conversion apparatus performs screen update in its own apparatus when receiving a screen update request of signal control information, and transmits a screen update request in the conversion destination protocol to the other terminal. This has the effect of promptly responding to a screen update request and reducing the waiting time for image output. Even if the communication protocol differs between multimedia communication terminals, communication with reduced communication quality and reduced processing delay Is possible.

Further, the screen update request of the signal control information of the multimedia communication protocol converter of the present invention is thinned out without transmitting a plurality of the signal control information in a predetermined short period of time, and the one on the opposite side of the screen update request receiving side is used. To the other multimedia communication terminal or the other multimedia communication terminal.

Therefore, the multimedia communication protocol conversion apparatus improves the transmission speed required for signal control and performs signal control processing by decimating and transmitting a plurality of screen update requests for signal control information in a short period of time instead of transmitting a plurality of requests. It has the effect of improving image quality and sound quality by reducing the amount, and the effect of preventing the image code amount from increasing beforehand. Even if the communication protocol differs between multimedia communication terminals, the deterioration and processing of communication quality Enables communication with reduced delay.

Further, the multimedia communication protocol conversion apparatus of the present invention can freeze the screen in its own device even if it receives the screen freeze request of the signal control information from the one multimedia communication terminal or the other multimedia communication terminal. Instead, the screen freeze request in the protocol of the conversion destination is transmitted to the one multimedia communication terminal or the other multimedia communication terminal opposite to the screen freeze request receiving side.

Therefore, the multimedia communication protocol converter does not execute the screen freezing in its own device even when receiving the screen freezing request of the signal control information, and transmits the screen freezing request in the conversion destination protocol. This has the effect of simplifying the apparatus, and enables communication with reduced communication quality and reduced processing delay even if the communication protocol differs between multimedia communication terminals.

Further, the multimedia communication protocol converter of the present invention, when receiving a screen freezing request of signal control information from the one multimedia communication terminal or the other multimedia communication terminal, freezes the screen within its own device. And transmitting the screen freeze request in the protocol of the conversion destination to the one multimedia communication terminal or the other multimedia communication terminal opposite to the screen freeze request receiving side.

Therefore, when receiving the screen freeze request of the signal control information, the multimedia communication protocol converter executes the screen freeze in its own device and transmits the screen freeze request in the conversion destination protocol. Has the effect of promptly responding to a screen freeze request and eliminating the possibility of transmitting a disturbed image at the time of screen freeze request and image freeze release. Even if the communication protocol differs between multimedia communication terminals, the communication quality Communication with reduced degradation and processing delay.

Further, in the multimedia communication protocol converter of the present invention, the screen freeze request of the signal control information is thinned out without transmitting a plurality of screens within a predetermined short period, and the one on the opposite side to the screen freeze request receiving side is used. To the other multimedia communication terminal or the other multimedia communication terminal.

Therefore, the multimedia communication protocol converter improves the transmission speed required for signal control and performs signal control processing by thinning out and transmitting a plurality of screen freeze requests for signal control information in a short period of time instead of transmitting a plurality of requests. It has the effect of improving image quality and sound quality by reducing the amount, and enables communication with reduced communication quality and reduced processing delay even if the communication protocol differs between multimedia communication terminals.

Further, at least one of the first multimedia communication terminal and the second codec of the multimedia communication protocol converter of the present invention is provided with a decoding unit and an encoding unit, and the decoding unit transmits the code from the decoding unit. It sends control information to the conversion unit.

Accordingly, the multimedia communication protocol converter transmits control information from the decoding unit to the encoding unit, so that the control information notified in-band of the image data and the audio data is transmitted between the multimedia communication terminals. It has a function of transmitting, and enables communication in which deterioration of communication quality and processing delay are suppressed even if communication protocols are different between multimedia communication terminals.

[0046]

Embodiments of the present invention will be described below with reference to FIG. FIG. 1 shows a system configuration diagram of a multimedia communication protocol converter according to an embodiment of the present invention. As shown in FIG. 1, a multimedia communication terminal 204 is connected via a communication network / switch 202 to
Connected to the line interface unit 206 of the device 201 which is the multimedia communication protocol conversion device of the present invention,
Communication is performed using the protocol of the multimedia communication terminal 204. On the other hand, the multimedia communication terminal 205 is connected to the line interface unit 207 of the apparatus 201 via the communication network / switch 203, and the multimedia communication terminal 2
Communication is carried out using the protocol of H.05.

In the apparatus 201, the multimedia multiplexing / separating unit 208 separates the multimedia data received by the line interface unit 206 into image / voice / control signals. The separated image data is decoded by the image codec (decoding unit) 217, and the image codec (encoding unit)
The data is encoded at 218 and reaches the multimedia multiplexing / demultiplexing unit 209 via the switch 219. The separated audio data is decoded by an audio codec (decoding unit) 211, encoded by an audio codec (encoding unit) 212, and passed through a switch 213 to the multimedia multiplexing / demultiplexing unit 20.
Reach 9 The separated control signal is interpreted by the system control unit 210 and controls all parts in the apparatus, and the control signal to be transmitted to the terminal is multimedia multiplexing / multiplexing.
The separation unit 209 is reached. The video / audio / control signal that has reached the multimedia multiplexing / demultiplexing unit 209 is multiplexed here, and the multimedia data is transmitted to the line interface unit 20.
7

Similarly, in the opposite direction, the line interface unit 2
At 07, the multimedia multiplexing / separating unit 207 separates the received multimedia data into video, audio, and control signals. The separated image data is decoded by an image codec (decoding unit) 220, and the image codec (encoding unit)
The data is encoded at 221 and reaches the multimedia multiplexing / demultiplexing unit 208 via the switch 222. The separated audio data is decoded by an audio codec (decoding unit) 214, encoded by an audio codec (encoding unit) 215, and passed through a switch 216 to the multimedia multiplexing / demultiplexing unit 20.
Reach 8. The separated control signal is interpreted by the system control unit 210 and controls all parts in the apparatus, and the control signal to be transmitted to the terminal is multimedia multiplexing / multiplexing.
The separation unit 208 is reached. The video / audio / control signal that has reached the multimedia multiplexing / demultiplexing unit 208 is multiplexed here, and the multimedia data is transmitted to the line interface unit 20.
Send to 6.

Here, the multimedia communication protocol conversion device 201 is, for example, 320; 324 / I,
H. The multimedia communication terminal 204 shall support H.324 / M mutual conversion. The H.324 / M terminal and the multimedia communication terminal 205 are H.324 / M terminals. It is assumed that there are 320 terminals.

In determining the protocol of the terminal, if there is protocol information in out-band information such as call setting information, this is used. If not, it is determined by the data received in-band. From the multimedia communication terminal 204 to the H.264 terminal
If the H.223 frame is received, It is determined to be a 324 / M terminal. From the multimedia communication terminal 205, the 140
H. without If the H.221 frame is received, H.221 is received. It is determined to be 320 terminals. V. If a V.140 signature pattern is received, 140 by the procedure of H.140. The presence or absence of the 324 / I protocol is determined.

The present apparatus 201 enables two multimedia communication terminals 204 and 205 to communicate with each other.

In FIG. 1, unlike FIG. 2, the DA conversion and AD conversion parts are not required. With this device 201, the image quality and sound quality are not degraded by DA conversion and AD conversion.
The two multimedia communication terminals 204 and 205 having different communication protocols can communicate with each other.

The following description focuses on multimedia data from the multimedia communication terminal 204 to the multimedia communication terminal 205.

When the output image frame from the image codec (decoding unit) 217 is in the QCIF format, if the multimedia communication terminal 205 has the QCIF format in the receiving capability, the image codec (encoding unit) 218 is used.
Also, the input image frame to be input into QCIF format.
This eliminates image quality degradation due to format conversion.
The same applies to other formats such as 4CIF, CIF, and SubQCIF.

The input to the image codec (decoding unit) 217 is H.264. 263, the multimedia communication terminal 205
H. If there is an H.263, the switch 219 bypasses the image codec (decoding unit) 217 and the image codec (encoding unit) 218. This makes it possible to completely eliminate image quality deterioration. This is described in H. 26
1, the same applies to other image coding rules such as MPEG4. Here, when the image data rate to the multimedia communication terminal 205 must always be higher than the image data rate from the multimedia communication terminal 204, the multimedia multiplexing / demultiplexing unit 209 inserts a fill frame. For example, if the multimedia communication terminal 204 is a 32 kbps H.264. 324 / M terminal, and the multimedia communication terminal 205 is a 64 kbps H.264 / M. H.320 terminal, Since the image data rate of the 320 is fixed,
Insert a BCH fill frame.

The input to the audio codec (decoding unit) is G. 723.1, the multimedia communication terminal 205
G. Switch 213 if there is 723.1
Thus, the audio codec (decoding unit) 211 and the audio codec (encoding unit) 212 are bypassed. As a result, sound quality deterioration can be completely eliminated. This is G. 7
28, G. The same applies to other speech coding rules such as 711 and AMR.

If the multimedia communication terminal 205 has an image receiving capability of H.264. 263 and H.E. This device 2 notifies the multimedia communication terminal 204 when it has only
MPEG4 is not notified as the reception capability of H.01. 263
And H. By limiting to 261 the image coding rules can be matched. For example, if the multimedia communication terminal 204 is H.264. 324 / M terminal, and the multimedia communication terminal 205 is H.324 / M terminal. In the case of the 320 terminal, since it is obvious that the multimedia communication terminal 205 does not have the receiving capability of MPEG4,
MPEG4 can be deleted in advance from the receiving capability of the apparatus 201 for notifying the device 4. H. 320 terminals are 4C
Since most of the devices do not support the IF format, the device 2 that notifies the multimedia communication terminal 204
Deleting 4CIF from the reception capability of 01 contributes to improvement of image quality and frame rate.

When the multimedia communication terminal 205 determines that the voice reception capability is G.264. 711 and G.R. 728 and G.R. If the device 201 has only G.723.1, the device 201 that notifies the multimedia communication terminal 204 receives the G.72. 723.1
G. Annex C is not notified. By restricting to 723.1, speech coding rules can be matched. For example, if the multimedia communication terminal 204 is H.264. 324 / M terminal, and the multimedia communication terminal 205 is H.324 / M terminal. 320 terminal, the multimedia communication terminal 205 is a G.320 terminal. 72
Since it is apparent that the device 201 does not have the receiving capability of 3.1 Annex C, it is determined from the receiving capability of the device 201 that notifies the multimedia communication terminal 204 of G.31. 723.1 Ann
exC can be deleted in advance.

If the multimedia communication terminal 205 has an image receiving capability of H.264. 263 and H.E. If the multimedia communication terminal 204 has only H.261, If transmission of H.263 can be requested, the image coding rules can be matched. For example, if the multimedia communication terminal 204 is H.264. 3
24 / M terminal, which has notified the transmission apparatus 201 of the transmission capability, and the multimedia communication terminal 205 has In the case of the H.320 terminal, even if the apparatus 201 has notified the multimedia communication terminal 204 of the receiving capability of MPEG4, the H.320 is transmitted to the multimedia communication terminal 204. 263
By requesting the transmission of the image coding rule, the image coding rules can be matched.

If the multimedia communication terminal 205 determines that the voice reception capability is G.264. 711 and G.R. 728 and G.R. If the multimedia communication terminal 204 has only G.723.1, the G.72. If transmission of 723.1 can be requested, the speech coding rules can be matched. For example, if the multimedia communication terminal 204 is H.264. 324 / M terminal, which has notified the transmission apparatus 201 of the transmission capability, and the multimedia communication terminal 205 has In the case of the terminal 320, even if the apparatus 201 notifies the multimedia communication terminal 204 of the AMR receiving capability, the G.320 terminal transmits the G.320 to the multimedia communication terminal 204. By requesting transmission of 723.1, speech coding rules can be matched.

When the multimedia communication terminal 204 is H.264. 32
4 / M terminal and multimedia communication terminal 205 are H.4 / M terminals. 32
0 terminal, 324 / M LoopBackOf
f, SystemLoop, MediaLoop (Vi
deo), MediaLoop (Audio) by H.E. 3
By converting the LCO, the LCD, the LDV, and the LCA in correspondence with each other and transmitting them to the partner terminal,
It is not necessary that the device 1 itself has a loopback function, and the device can be simplified. LogicalChannelLoop
(Video) and LogicalChannelLoo
p (Audio) is described in H.A. Since the 320 terminal cannot be realized, a rejection response is sent to them.

H. The H.320 terminal is a compliant recommendation of H.320.
From the characteristics of H.242, there are terminals that issue many LCOs during normal communication (for example, once every 100 ms). This is converted to LoopBackOff, and all data are converted to H.264. 324
Since it does not make sense to transmit to the / M terminal, the present apparatus 201 manages only the state of the loopback, and the control channel speed can be reduced by converting and transmitting only when the state is changed. Sending a loopback command, even if the status has not changed, just by thinning out the same loopback command has the effect of eliminating the possibility of state mismatch due to loss due to transmission errors, etc., and controls according to the error rate. A trade-off with the channel speed reduction effect can be achieved. H. When the control channel speed is fixed as in 320, it is effective to increase the error tolerance by multiplying and transmitting the loopback command.

When the apparatus 201 receives a screen update request (FastUpdate) from the multimedia communication terminal 204, the screen update request (Fa) is sent to the multimedia communication terminal 205 via the multimedia multiplexing / demultiplexing unit 209.
By issuing (stUpdate), there is no need to instruct the image codec (encoding unit) 221 to update the screen from the system control unit 210, and the apparatus is simplified. If this instruction is issued, a screen update request (FastUpdated)
e) The response to the request can be made quicker, and a trade-off with system simplification can be achieved due to a user request for image output time or transmission delay.

The transmission factors of the screen update request (FastUpdate) to the multimedia communication terminal 205 include the reception of the screen update request (FastUpdate) from the multimedia communication terminal 204 and the request from the image codec (decoding unit) 220. Conceivable. Particularly, at the start of communication, etc., these requests often occur in a short period of time.
By transmitting the data to the multimedia communication terminal 205 collectively as “stUpdate”, the amount of image code from the multimedia communication terminal 205 can be reduced.

Screen update freeze from multimedia communication terminal 204 (FreezePictureRequest)
Is received by the apparatus 201, the multimedia multiplexing /
Multimedia communication terminal 205 via separation unit 209
Request to freeze screen (FreezePictureReq
est), there is no need to instruct the image codec (decoding unit) 217 to freeze the screen from the system control unit 210, and the apparatus is simplified. If this instruction is given, a screen freeze request (FreezePictureR)
request) and the multimedia communication terminal 205 at the time of screen freeze request and screen freeze release.
It is possible to eliminate the possibility of transmitting a disturbed image, and to make a trade-off with system simplification.

Control signals other than a loopback command, a screen update request, and a screen freeze request can be similarly implemented.

The screen codec (FreezePict) received by the image codec (decoding unit) 217 in-band is released.
ureRelease) is transmitted to the image codec (decoding unit) 218 and used for encoding. Thereby, the screen freeze release (Freeze) which is the in-band control information is performed.
(PictureRelease) can be transmitted to the multimedia communication terminal 205.

Also, efficient coding is performed by transmitting in-band control information such as intra / inter control and Q control from the image codec (decoding unit) 217 to the image codec (encoding unit) 218. It becomes possible. The same applies to the audio codec (decoding unit) 211 to the audio codec (encoding unit) 212.

While the above description has been made focusing on multimedia data from the multimedia communication terminal 204 to the multimedia communication terminal 205, the same can be applied to the opposite direction.

Also, if the multimedia communication terminal 204 is H.264. 324 / M terminal and multimedia communication terminal 205 are H.324 / M terminals. Although the description has been given of an example in which the terminal is the H.320 terminal, these are H.320 terminals. 324 / M, H.E. The same applies to other multimedia protocols such as H.323, and other image coding rules and audio coding rules used by these protocols can be similarly implemented.

[0071]

According to the multimedia communication protocol conversion apparatus of the present invention, the audio code and the image code are converted by converting the audio code and the image code in accordance with the multiplexing system and the communication control system of the different multimedia communication protocols. Even if the communication protocol is different between the multimedia communication terminals, it is possible to perform the communication while suppressing the deterioration of the communication quality and the processing delay.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a multimedia communication protocol converter according to an embodiment of the present invention.

FIG. 2 is a system configuration diagram of a conventional method for performing communication protocol conversion by cascading multimedia communication terminals.

[Explanation of symbols]

101, 102, 204, 205 Multimedia communication terminal 103, 104 Multimedia communication terminal for protocol conversion 105, 106, 202, 203 Communication network / switch 201 Multimedia communication protocol conversion device 206, 207 Line interface unit 208, 209 Multi Media multiplexing / demultiplexing unit 210 System control unit 211, 214 Voice codec (decoding unit) 212, 215 Voice codec (coding unit) 217, 220 Image codec (decoding unit) 218, 221 Image codec (coding unit) 213 , 216, 219, 222 switch

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B089 GA31 JB06 KC01 KC23 KC52 KF05 5K034 AA03 CC02 CC05 DD01 FF02 HH01 HH02 HH16 HH61 HH63 JJ24 5K101 KK03 KK20 LL01 LL03 LL11 MM06 MM07 NN34 RR

Claims (20)

[Claims] 1. A line interface unit for communicating with one multimedia communication terminal, and decoding and encoding of communication data obtained by separating multimedia communication data received by the one line interface unit. A first codec unit; and another line interface unit for transmitting multimedia communication data obtained by multiplexing communication data from the first codec unit to the other multimedia communication terminal; Determine the protocol of the terminal, select a code that enables communication from the one multimedia communication terminal to the other multimedia communication terminal, perform encoding of the first codec unit, the one and the other Multimedia communication protocol converter for performing communication between multimedia communication terminals Place. A second codec unit for decoding and encoding each communication data obtained by separating the multimedia communication data received from the other multimedia communication terminal by the other line interface unit, The protocol of the one multimedia communication terminal is determined, a code enabling communication with the one multimedia communication terminal is selected, and the encoding of the second codec unit is performed. 2. The multimedia communication protocol converter according to claim 1, wherein the communication between the media communication terminals is performed. 3. The method according to claim 1, wherein at least one of the first codec unit and the second codec unit performs decoding to a digital image frame and encoding from a digital image frame. The multimedia communication protocol converter according to the above. 4. The apparatus according to claim 1, wherein at least one of the first codec unit and the second codec unit performs decoding into digital audio and encoding from digital audio. Multimedia communication protocol converter. 5. The method according to claim 1, wherein at least one of the first codec unit and the second codec unit matches a format of the digital image frame to be encoded with a format of the decoded digital image frame. The multimedia communication protocol converter according to claim 3. 6. At least one of the first codec unit and the second codec unit is separated when the coding rule of an image can be matched with the decoding rule, and the decoding and coding in the own apparatus are performed. 3. The multimedia communication protocol conversion device according to claim 1, wherein the conversion is not performed. 7. At least one of said first codec and said second codec is disconnected when the coding rule of the speech can be matched with the decoding rule,
3. The multimedia communication protocol converter according to claim 1, wherein decoding and encoding are not performed in the own device. 8. The image receiving capability of notifying at least one of the one multimedia communication terminal and the other multimedia communication terminal is limited to a predetermined capability. 5. The multimedia communication protocol converter according to any one of 5. 9. The voice receiving capability for notifying at least one of the one multimedia communication terminal and the other multimedia communication terminal is limited to a predetermined capability. 8. The multimedia communication protocol converter according to any one of 7. 10. The digital video frame format and transmission coding rule selection control for at least one of the one multimedia communication terminal and the other multimedia communication terminal. ,
6. The multimedia communication protocol converter according to any one of 3 and 5. 11. The transmission coding rule selection control for at least one of the one multimedia communication terminal and the other multimedia communication terminal. A multimedia communication protocol converter according to any one of the above. 12. Even if a command for loopback of signal control information is received from the one multimedia communication terminal or the other multimedia communication terminal, loopback is not performed in the own device, and a conversion destination protocol is 3. The method according to claim 1, wherein if there is a corresponding loopback command, the command is converted and transmitted to the one multimedia communication terminal or the other multimedia communication terminal on the opposite side of the command receiving side. The multimedia communication protocol converter according to the above. 13. When the loopback command is continuously received from the one multimedia communication terminal or the other multimedia communication terminal, the converted loopback command is thinned out and the opposite side of the command is received. 13. The multimedia communication protocol converter according to claim 12, wherein the transmission is performed to the one multimedia communication terminal or the other multimedia communication terminal. 14. Even if a screen update request for signal control information is received from the one multimedia communication terminal or the other multimedia communication terminal, the screen update is not performed in the own apparatus, and the screen update in the conversion destination protocol is performed. 3. The multimedia communication protocol conversion device according to claim 1, wherein the request is transmitted to the one multimedia communication terminal or the other multimedia communication terminal on the opposite side of the screen update request receiving side. 15. When receiving a screen update request for signal control information from the one multimedia communication terminal or the other multimedia communication terminal, the screen update is performed in the own apparatus, and the screen update in the conversion destination protocol is performed. 3. The multimedia communication protocol conversion device according to claim 1, wherein the request is transmitted to the one multimedia communication terminal or the other multimedia communication terminal on the opposite side of the screen update request receiving side. 16. The screen update request of the signal control information,
16. The method according to claim 14, further comprising: thinning out a plurality of transmissions within a predetermined short period of time and transmitting the screen update request to the one multimedia communication terminal or the other multimedia communication terminal on the side opposite to the reception side of the screen update request. 2. The multimedia communication protocol converter according to claim 1. 17. Even if a screen freezing request of signal control information is received from the one multimedia communication terminal or the other multimedia communication terminal, the screen freezing is not performed in the own device, and the screen freezing in the conversion destination protocol is performed. 3. The multimedia communication protocol conversion device according to claim 1, wherein the request is transmitted to the one multimedia communication terminal or the other multimedia communication terminal on the opposite side of the screen freeze request receiving side. 18. When receiving a screen freezing request of signal control information from the one multimedia communication terminal or the other multimedia communication terminal, the screen freezing is performed in its own device, and the screen freezing in a conversion destination protocol is performed. 3. The multimedia communication protocol conversion device according to claim 1, wherein the request is transmitted to the one multimedia communication terminal or the other multimedia communication terminal on the opposite side of the screen freeze request receiving side. 19. The screen freeze request of the signal control information,
19. The method according to claim 17, further comprising: thinning out a plurality of transmissions in a predetermined short period, and transmitting the screens to the one multimedia communication terminal or the other multimedia communication terminal on the side opposite to the screen freeze request receiving side. 2. The multimedia communication protocol converter according to claim 1. 20. At least one of the first multimedia communication terminal and the second codec unit includes a decoding unit and an encoding unit, and transmits control information from the decoding unit to the encoding unit. The multimedia communication protocol converter according to claim 1 or 2, wherein: