JPH08130514A - Picture communication terminal equipment - Google Patents

Abstract

PURPOSE: To improve the movement of an image and the quality of sound by changing the transmission capacity of sound data in accordance with the compression encoding quantity of picture data. CONSTITUTION: A difference data computing part 15 calculates a data quantity difference value between frames compression-encoded by a moving picture control part 9. A difference data comparing part 16 compares the difference value calculated by the computing part 15 with a previously determined specific value. A BAS code setting part 17 determines the transmission capacity of sound data based upon a compared result from the comparing part 16 and sets upon a BAS code indicating the determined transmission capacity of the sound data. A BAS code control part 13 controls a switch control part 18 in accordance with the BAS code set up by the setting part 17 and switches the transmission capacity of the sound data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image communication terminal device having a multiplex transmission function for voice data, moving image data and still image data.

[0002]

2. Description of the Related Art In recent years, CCITT (now ITU-TS: International Telegraph and Telephone Advisory Committee) recommendation officially recommends a video coding method, a still image coding method, a multiplexing method and a communication procedure for audiovisual services. Was converted into
Along with this, image communication terminal devices such as a video conference system and a video phone, which comply with the recommendations, have been developed by various companies.

FIG. 2 is a functional block diagram of a conventional image communication terminal device. The image communication terminal device 100 of FIG. 2 includes a voice control unit 8, a moving image control unit 9, a still image control unit 10, a multiplexing / demultiplexing unit 11, a line interface unit 12, a BAS (Bit-rate Allocation Signal). ) A code control unit 13 and a call control processing unit 14 are included.

The voice control unit 8 has a microphone 1 for inputting voice.
And a speaker 2 for outputting sound are connected. The moving image control unit 9 includes a photographing camera 3 and a document camera 4.
Is connected. Further, the moving image control unit 9 and the still image control unit 10 are connected to a monitor 5 that displays an image sent from the partner device or an image captured by the image capturing camera 3 or the document camera 4. Further, a scanner 6 for capturing a still image is connected to the still image control unit 10. A key operation unit 7 for inputting a telephone number and selecting a function is connected to the call control processing unit 14.

The voice control unit 8 compression-codes and decompresses voice data. The moving image control unit 9 compression-codes and decompresses moving image data. The still image control unit 10 compression-codes and decompresses still image data.

The multiplexer / separator 11 converts the audio data, the moving image data and the still image data into CCITT (current ITU-
TS) Recommendation H. In addition to multiplexing with the frame format according to 221, the frame transmitted from the partner device is separated into audio data, moving image data, and still image data. Here, CCITT (currently ITU-TS) Recommendation H.264. 221 defines the frame structure of 64 kbps to 1920 kbps channels in audiovisual teleservices.

[0007] The BAS code control unit 13 is a CCITT (current ITU-TS) recommendation H.264 standard. The communication procedure based on 242 is executed. Here, CCITT (currently ITU-TS) Recommendation H.264. 242 defines a method for setting communication between audiovisual terminals using digital channels up to 1920 kbps.

The call control processor 14 manages calls such as incoming and outgoing calls and disconnections. The multiplexer / demultiplexer 11 is connected to an ISDN (Integrated Service Digital Network) 20 via a line interface 12.

FIG. 3 shows CCITT (current ITU-TS) Recommendation H.264. 22 shows a multiplexing frame structure defined by H.221. As shown in FIG. 2, subchannels 1 to 7 are allocated to bit numbers 1 to 7, respectively, and a frame synchronization signal (FAS) and a bit rate allocation signal (B
AS) and sub-channel 8 are assigned.

In FIGS. 4 and 5, CCITT (current ITU-
TS) Recommendation H. 221 shows a numerical table of BAS codes defined by H.221.

This numerical table shows the BAS code in 8 bits, and the column header shows the attribute in the form of bits (b0, b1, b2). Bit (000) in FIG. 4 indicates an audio command, and bit (001) indicates a transfer rate command. Bit (010) indicates video or other command, and bit (011) indicates LSD (low speed data) /
3 shows an MLP (Multi Layer Protocol) command. Bit (100) in FIG. 5 indicates audio / transfer rate capability, bit (101) indicates data / video capability, and bit (111) indicates escape. The leftmost column of the numerical table shows the values in decimal notation of bits [b3, b4, b5, b6, b7]. For example, "chan. # 6" is (001)
It has a value of [10110].

Next, the image communication terminal device 10 shown in FIG.
The operation of 0 will be described. When the operator sets the telephone number of the partner device using the key operation unit 7 and presses the call key, the call control processing unit 14 connects the partner device with the B channel via the line interface unit 12. .

After the connection is completed, the BAS code control unit 13 uses the B channel and CCITT (current ITU-TS) recommendation H.264.
Based on 242, frame synchronization is established. After the synchronization is established, the reception capability notified from the other device using the values of the audio / transfer rate capability and the data / video capability of the BAS code numerical table shown in FIG. 5 is referred to as the transmission capability of the image communication terminal device 100. By comparison, the operation mode is determined so as to perform the communication with the common maximum function. Then, the BAS code control unit 13 transmits a command (audio command, transfer rate command, and other command) indicating the determined operation mode to the partner device by using the BAS code shown in FIG. Command mode switching.

After that, when transmitting the moving image data to the other party's device, the moving image control unit 9 sends the moving image data fetched from the photographing camera 3 and the document camera 4 to the NTS.
C system (National Television System Committee; Japanese and US television systems) and PAL system (Ph
ASE Alternation by Line color television; CIF (luminance signal Y: 352 x 288, color difference signal CB, CR: 176 x 144) or QCIF, which is an intermediate video signal format common to European television systems.
(Luminance signal Y: 176 × 144, color difference signals CB, C
R: 88 × 72) and then compressed.

When the transmission request key is pressed by the key operation unit 7, the moving image control unit 9 outputs the processed moving image data to the multiplexing / demultiplexing unit 11. The multiplexing / separating unit 11 multiplexes the moving image data with other data to form a frame having the structure shown in FIG. 3, and transmits the frame from the line interface unit 12 to the partner device via the ISDN 20.

The transmission capacity provided by a single channel of the ISDN 20 is 64 kbps, 384 kbps or 1536/1920 kbps, but if the transfer capability of both terminal devices permits, a plurality of these channels should be used. It is also possible to set a transmission capacity line having an intermediate value and perform data transmission by the set line. For example, if two 64 kbps channels are used, 1
A line with a transmission capacity of 28 kbps can be set. In this case, additional call setup is performed after it has been confirmed that the terminal devices on both the transmitting side and the receiving side have the transfer capability of using multiple channels in the capability exchange by the B channel connected first. , Channels are added.

[0017]

However, in the above-mentioned image communication terminal device 100, communication is performed in the mode set in the first capability exchange regardless of the compression code amount of image data. Therefore, even if the movement of the subject is strong and the compression code amount of the image data increases, the transmission capacity of the audio data does not change and the movement of the image becomes awkward.
On the other hand, if the transmission capacity of the audio data is set to be small in the first capacity exchange, the transmission capacity of the audio data does not change even if the motion of the subject is small and the compression code amount of the image data is small. Therefore, there is a problem in that it is impossible to smooth the awkward motion of the image and to make the voice clearer.

It is an object of the present invention to provide an image communication terminal device capable of improving the motion and sound quality of an image by changing the transmission capacity of audio data according to the compression code amount of image data.

[0019]

[Means for Solving the Problems]

(1) First Invention An image communication terminal device according to a first invention is a voice control means,
A moving image control means, a communication means, a difference value calculation means, a difference value comparison means, and a transmission capacity control means are provided.

The voice control means compresses and encodes the voice data. The moving picture control means compresses and codes the moving picture data. The communication means multiplexes the audio data compression-encoded by the audio control means and the moving image data compression-encoded by the moving image control means, and transmits the multiplexed data. The difference value calculating means calculates a difference value of the data amount between frames of the moving image data compressed and encoded by the moving image control means. The difference value comparing means compares the difference value calculated by the difference value calculating means with a predetermined threshold value. The transmission capacity control means controls the transmission capacity of the voice data in the communication means based on the comparison result by the difference value comparison means.

(2) Second Invention In the image communication terminal device according to the second invention, in the configuration of the image communication terminal device according to the first invention, the transmission capacity control means comprises a BAS code setting means and a BAS code control. It includes means.

The BAS code setting means determines the transmission capacity of the audio data based on the comparison result by the difference value comparing means.
Set by sign. The BAS code control means switches the transmission capacity of the audio data in the communication means based on the BAS code set by the BAS code setting means.

(3) Third Invention In the image communication terminal device according to the third invention, in the configuration of the image communication terminal device according to the first invention, the moving image control means sends moving image data from the document camera. When given, the use of the document camera is detected, and the transmission capacity control means switches the transmission capacity of the audio data in response to the detection by the moving picture control means.

[0024]

In the image communication terminal device according to the first to third inventions, the difference value of the data amount between the frames of the compression-encoded moving image data is calculated, and the calculated difference value is predetermined. The transmission capacity of voice data is controlled based on the result of comparison with the threshold value.

Therefore, when the difference in the data amount between frames is large, that is, when the compression code amount of image data is large, the transmission capacity of audio data is set to be small. Thereby, the movement of the image is smoothly improved.

On the contrary, when the difference in the data amount between the frames is small, that is, when the compression code amount of the image data is small, the transmission capacity of the audio data is set large. Thereby, the sound quality is improved.

In particular, in the image communication terminal device according to the third aspect of the invention, when the document camera is used, the use of the camera is detected and the transmission capacity of the audio data is switched. Therefore, in the case of the document mode in which a still document is photographed, the transmission capacity of audio data is set to the maximum and the sound quality is improved to the maximum.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a functional block diagram of an image communication terminal device according to an embodiment of the present invention. This image communication terminal device is used, for example, in a video conference. 1 and 2
In FIG. 6, the same or corresponding parts are designated by the same reference numerals, and the description thereof will be omitted.

The image communication terminal device 100a shown in FIG. 1 differs from the image communication terminal device 100 shown in FIG. 2 in that a difference data calculation unit 15, a difference data comparison unit 16, and a BAS code setting unit 17 are provided.
Further, the switching control unit 18 is further provided.

The difference data calculation unit 15 includes a moving image control unit 9
Then, the difference value of the data amount between the compression-encoded frames is calculated. The difference data comparison unit 16 compares the difference value calculated by the difference data calculation unit 15 with a predetermined specific value (amount of data at the threshold level). The BAS code setting unit 17 determines the CCITT (current ITU-TS) recommendation H.264 based on the comparison result of the difference data comparison unit 16. The BAS code defined in 221 is set. Switching control unit 18
Switches between moving image control and voice control in the BAS code control unit 13 according to the BAS code set by the BAS code setting unit 17.

In this embodiment, the multiplexing / demultiplexing unit 11 and the line interface unit 12 constitute communication means.
Further, the difference data calculation unit 15 constitutes a difference value calculation unit, the difference data comparison unit 16 constitutes a difference value comparison unit,
The BAS code setting unit 17, the BAS code control unit 13, and the switching control unit 18 constitute transmission capacity control means.

Next, the operation of the image communication terminal device 100a shown in FIG. 1 will be described. When the operator sets the telephone number of the other device (the image communication terminal device 100a on the receiving side) using the key operation unit 7 and presses the call key, the call control processing unit 14 causes the other device via the line interface unit 12. The B channel is connected to and from.

After the connection is completed, the BAS code control unit 13
CCITT (currently ITU-TS) Recommendation H.264 Based on 242, frame synchronization is established. After the synchronization is established, the audio data of the BAS code numerical table shown in FIG.
The reception capability notified from the partner device using the numerical values of the transfer rate capability and the data / video capability is compared with the transmission capability of the image communication terminal device (image communication terminal device on the transmission side) 100a, and the maximum common function is used. The operation mode is determined so that the communication is performed. Then, the BAS code control unit 13 transmits a command (audio command, transfer rate command and other command) indicating the determined operation mode to the partner device by using the BAS code shown in FIG. Command mode switching.

After that, when the moving image data is transmitted to the other party's device, the moving image control unit 9 sends the moving image data fetched from the photographing camera 3 and the document camera 4 to the NTS.
It is converted to CIF or QCIF which is an intermediate video signal format common to the C system and the PAL system and compressed.

When the transmission request key is pressed by the key operation unit 7, the moving image control unit 9 outputs the processed moving image data to the multiplexing / separating unit 11. The multiplexing / demultiplexing unit 11 multiplexes the moving image data with other data to form a frame having the structure shown in FIG. 3, and transmits the frame from the line interface unit 12 to the partner device via the ISDN 20.

As described in the description of the image communication terminal apparatus 100 of FIG. 2, the transmission capacity provided by the single channel of the ISDN 20 is 64 kbps, 384 kbps or 1536/1920 kbps, but both terminal apparatuses have the same transmission capacity. If the transfer capability permits, a plurality of these channels can be used to set a line having a transmission capacity having an intermediate value, and data can be transmitted by the set line.

In this embodiment, the initial (initial) frame data compression-coded by the moving picture control unit 9 is taken into the memory in the difference data calculation unit 15. Then, similarly, when the scene is changed, the frame data compressed and encoded by the moving image control unit 9 is taken into the difference data calculation unit 15. Difference data calculation unit 1
Reference numeral 5 calculates a difference value between the data amount of the initial frame data and the data amount of the frame data when the scene is changed, and gives the calculation result to the difference data comparison unit 16. The difference data comparison unit 16 compares the difference value given from the difference data calculation unit 15 with a predetermined specific value,
The comparison result is given to the BAS code setting unit 17.

The BAS code setting unit 17 determines the transmission capacity of the voice data based on the comparison result given from the difference data comparison unit 16, and the voice determined according to the numerical table of the BAS code shown in FIGS. 4 and 5. A BAS code indicating the data transmission capacity is set. That is, the BAS code setting unit 1
No. 7 sets the BAS code so that the transmission capacity of the audio data becomes small when the difference value is larger than the specific value, and the BAS code so that the transmission capacity of the audio data becomes large when the difference value is smaller than the specific value. Set the sign. The BAS code control unit 13 sets B set by the BAS code setting unit 17.
The switching control unit 18 is controlled according to the AS code to switch the transmission capacity of voice data.

Next, when the operator switches the photographing camera 3 to the document camera 4, the moving picture control section 9 informs the BAS code setting section 17 so as to automatically maximize the transmission capacity of the audio data. give. For example, at the time of communication at 128 kbps, the BAS code setting unit 17 automatically sets the transmission capacity of voice data to 64 kbps.
The code is set, and the setting result is given to the BAS code control unit 13. The BAS code control unit 13 controls the switching control unit 18 according to the set BAS code to switch the transmission capacity of voice data.

As described above, the image communication terminal device 1 of this embodiment
At 00a, the BAS code is set by calculating the difference value of the data amount between frames and comparing the difference value with a predetermined specific value. Further, in the case of the writing mode, it is possible to set the maximum transmission capacity of audio data while transmitting image data in the communication state. In this way, since the transmission capacity of the audio data is set according to the compression code amount of the image data, the transmission capacity of the audio data is set small when the movement of the subject is intense,
When the movement of the image is smoothed and the movement of the subject is small, the transmission capacity of the audio data is set to be large, and the sound quality is improved. In this way, it becomes possible to automatically realize a realistic video conference.

[0042]

As described above, according to the present invention, there is provided an image communication terminal device in which the transmission capacity of audio data is controlled according to the compression code amount of image data. Therefore, when the movement of the subject is intense, the transmission capacity of the audio data is set to be small, and the movement of the image is smoothed. Further, when the movement of the subject is small, the transmission capacity of the audio data is set to be large, and the sound quality is improved.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an image communication terminal device according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of a conventional image communication terminal device.

FIG. 3 CCITT (current ITU-TS) Recommendation H.264. 221
Of the multiplex frame structure specified in

FIG. 4 CCITT (current ITU-TS) Recommendation H.264. 221
Showing a numerical table of BAS codes defined in

FIG. 5: CCITT (current ITU-TS) Recommendation H.264. 221
Showing a numerical table of BAS codes defined in

[Explanation of symbols]

 1 Microphone 2 Speaker 3 Shooting Camera 4 Document Camera 5 Monitor 6 Scanner 7 Key Operation Section 8 Voice Control Section 9 Moving Image Control Section 10 Still Image Control Section 11 Multiplex / Demultiplex Section 12 Line Interface Section 13 BAS Code Control Section 14 Calls Control processing unit 15 Difference data calculation unit 16 Difference data comparison unit 17 BAS code setting unit 18 Switching control unit 20 ISDN 100a Image communication terminal device

Claims (3)

[Claims] 1. A voice control means for compressing and encoding voice data, a moving image control means for compressing and encoding moving image data, a voice data compression coded by the voice controlling means and the moving image control means. A communication unit that multiplexes and transmits the compression-encoded moving image data, and a difference value calculation unit that calculates a difference value of the data amount between frames of the moving image data that has been compression-encoded by the moving image control unit. Difference value comparison means for comparing the difference value calculated by the difference value calculation means with a predetermined threshold value, and transmission capacity of voice data in the communication means based on the comparison result by the difference value comparison means An image communication terminal device comprising: 2. The transmission capacity control means, a BAS code setting means for setting a transmission capacity of audio data by a BAS code based on a comparison result by the difference value comparison means, and a BAS set by the BAS code setting means. The image communication terminal device according to claim 1, further comprising: a BAS code control unit that switches a transmission capacity of voice data in the communication unit based on a code. 3. The moving image control means detects use of the document camera when moving image data is given from the document camera, and the transmission capacity control means responds to the detection by the moving image control means. 2. The image communication terminal device according to claim 1, wherein the transmission capacity of voice data in the communication means is switched.