JPH04179385A - Multimedia communication equipment - Google Patents

Abstract

PURPOSE:To prevent the pause of a received picture before the departure of a frame synchronization and after the recovery of the frame synchronization by displaying a still picture in a received picture memory part at a picture display part during the recovery of the frame synchronization, and displaying the received picture at the picture display part after the recovery of the frame synchronization, at the time of the generation of the departure of the frame synchronization. CONSTITUTION:At the time of the generation of the departure of the frame synchronization during a picture data communication with the other side terminal, the generation of the departure of tire frame synchronization is communicated from a multiplexing/separating part 17 to a system controlling part, the input of a picture switching part 93 which outputs a picture data input from a video encoding/decoding part 10 to a picture display part 8, is switched to the input from a received picture memory part 91. Then when the system controlling part receives the information of the recovery of the frame synchronization, the input of the picture switching part 93 is switched to the input from the video encoding and decoding part displays the received picture at the picture display part 8, and then starts the fetch of the received picture to the received picture memory part 91. Thus, the pause of the received picture before the departure of the frame synchronization and after the recovery of the frame synchronization, can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multimedia communication device connected to an I5DN (Integrated Service Digital Communication Network).

(Prior Art) In recent years, communication services using 15DN lines have been put into practical use, and AV [Audi.

Visual) services are attracting attention, and AV
CCITT (International Telegraph and Telephone Consultative Committee) Recommendation (or Draft Recommendation) rH, 221J, r
It has been announced as H, 242J, rH, 32cN, etc. rH, 221J, 64 kbps ~ 1920
BAS (Bil-rate Allocation) is used for exchanging frame structures and terminal capabilities, specifying communication modes, etc. in AV services on kbPS channels.
A coding assignment for Sig+++l) is defined.

In rH, 242J, protocols such as capability exchange and communication mode switching between AV terminals using BAS are defined, and in rH, 320J, system aspects of AV services in general are defined. [H1221J describes the frame structure, frame synchronization loss, and recovery.

r) (, 242J describes the process when frame synchronization occurs.According to it, when frame synchronization occurs and it is detected on the receiving side, timer T3 (10 seconds) is set and the frame is An attempt is made to regain synchronization. If frame synchronization is restored before the timer expires,
Normal operation resumes. If frame synchronization is not recovered before the timer expires, synchronization is performed from the beginning.

(Problem to be Solved by the Invention) However, in conventional multimedia communication devices connected to the ISDN basic interface, when frame synchronization occurs during image data reception, a distorted image is displayed. Furthermore, there was a problem in that the reception screen before the frame synchronization was lost and after the frame synchronization was recovered was interrupted.

The present invention has been made in view of the above-mentioned circumstances, and is designed so that when frame synchronization occurs during image data reception, a distorted image is not displayed, and the receiving screen before frame synchronization and after frame synchronization is not interrupted. The purpose is to provide a multimedia communication device that can

(Means for Solving the Problems) In order to achieve the above object, the multimedia communication device of the present invention includes an image display unit, a received image memory unit that stores a certain amount of received images, and an operation screen memory unit that stores an operation screen. an image memory unit; a switch for selectively switching between inputting the received image into the received image memory and not inputting the received image; and an image switching section for selecting whether to input either the output of the received image or the output of the received image, and when a frame synchronization occurs and while the synchronization is being recovered, the still image in the received image memory section is displayed on the image display section. Further, after frame synchronization is recovered, the received image is displayed on the image display section.

Further, when the frame synchronization is not recovered even after a certain period of time has elapsed, it is desirable that the output from the operation screen image memory section be displayed on the image display section.

(Function) When frame synchronization occurs, a still image in the received image memory section is displayed on the image display section while the frame synchronization is being recovered, and after frame synchronization is recovered, the received image is displayed on the image display section. Further, if the frame synchronization is not recovered even after a certain period of time has elapsed, the output from the operation screen image memory section is displayed on the image display section.

(Example) Hereinafter, one example of the present invention will be described based on the drawings. 1st
The figure is a block configuration diagram of a multimedia communication device according to the present invention. In the figure, l is a handset (handset) which is one of the audio input/output means of this device, and 2 is an audio input device of this device. 3 is a speaker which is one of the audio output means of this device, and these handset 1, microphone 2 and speaker 3 are connected to an audio interface unit 4. This audio interface unit 4 operates according to instructions from a system control unit 14, which will be described later.
a switching process for switching the operation of the hand cent 1, microphone 2, and speaker 3 as audio input/output means;
On/off-hook detection processing for detecting whether the handset 1 is in an on-hook state or an off-hook state; echo cancellation processing for canceling echoes when the microphone 2 and speaker 3 as audio input/output means are activated , and generates tones such as dial tone, ring tone, busy tone, ring tone, etc., and is connected to the voice encoding/decoding section 5. This audio encoding/decoding unit 5 performs 64 kbps PCM A-1aw, 64 kbp
s PCM μmlaw, 64kbps156kb
ps/48kbps SB-ADPCM, 32kbp
s ADP-CM, 16kbps (e.g. APC-A
B), the transmitted audio signal is encoded and the received audio signal is decoded according to an audio signal encoding/decoding algorithm such as 8 kbps. 6 is one of the image input means of this device, and is a camera for inputting self-portraits, etc. 7 is one of the image input means of this device, and is a document camera for inputting pictures, drawings, etc.; 8 is a camera 6, or an image display unit that displays the input image from the document camera 7, the image received from the other party, the operation screen, etc.
, and the image display section 8 are connected to the video interface section 9. The video interface section 9 performs image input means switching processing, according to instructions from the system control section 14.
The video encoding/decoding unit performs display switching processing of input images, received images, and operation screens on the image display unit 8, and image signal synthesis processing for displaying them separately on the image display unit 8. 10. This video encoding/decoding unit 10 complies with the CCITT recommendation draft rH.

This encoder encodes a transmitted image signal and decodes a received image signal in accordance with H.261. 11 is a data terminal for performing data communication, and a data interface section 1
Connected to 2. This data interface section 12
notifies the data terminal 11 and the transmission data from the system control unit 14 to the demultiplexing unit 17, which will be described later.
It notifies the data terminal 11 or the system control unit 14 of received data. Reference numeral 13 denotes an operation section such as a keyboard and a touch panel used for inputting control information for general control of this device; an audio interface section 4;
audio encoding/decoding section 5, video interface section 9,
It is connected to a system control section 14 together with a video encoding/decoding section 10 and a data interface section 12 . This system control unit 14 includes a CPU, ROM, RAM,
It is equipped with an auxiliary storage device, etc., and controls the entire device by monitoring the status of each part, creating operation/display screens according to the status, and executing application programs.The D channel performs call control. It has a control section 15 and an in-channel control section 16 that performs in-channel control. The audio encoding/decoding section 5, the video encoding/decoding section 10, and the data interface section 12 are connected to a multiplexing/demultiplexing section 17. This demultiplexer 17 is
Transmits the audio signal from the audio encoder/decoder 5, the image signal from the video encoder/decoder 10, the data from the data interface unit 12, and the BAS from the system controller 14 in accordance with CITT recommendations rH, 221J. It multiplexes frame by frame, separates the received frame into each component media, and notifies each part,
It is connected to the system control section 14 and the line interface section 18. This line interface section 18 is 15D
It controls the line according to the N user/network interface.

FIG. 2 is a block diagram showing in detail the configuration of the video interface section 9, which is a main part of the apparatus of the present invention, and the flow of image data output to the image display section 8. As clearly shown in the figure, the video interface section 9 is connected to the received image memory section 9.
1, an operation screen image memory section 9□, and an image switching section 93
and a switch (SW) 94. The received image memory section 91 stores a fixed number of frames of the output image from the video encoding/decoding section 10.The operation screen image memory section 9□ stores the operation screen. The image switching section 93 switches the image from the video encoding/decoding section 10, the image from the received image memory section 91, and the image from the operation screen image memory section 9□ according to instructions from the system control section 14. The switch 94 selectively switches between inputting the output image from the video encoding/decoding section 10 to the received image memory section 91 and not inputting it to the received image memory section 91. It is.

Next, the operation of the multimedia communication device of the present invention will be explained with reference to the flowchart of FIG.

First, when frame synchronization occurs during image data communication with a partner terminal, the multiplexing/demultiplexing section 17 notifies the system control section 14 of the occurrence of frame synchronization (step 1). In the next step 2, timer T3 (10 seconds)
Start. Note that this timer value of 10 seconds is specified in CCITT Recommendation rH, 242J. Next, the input of the image switching unit 93, which outputs the image data input from the video encoding/decoding unit 10 to the image display unit 8 during normal operation, is switched to the input from the received image memory unit 91 (step 3). ). Next, during normal operation, image data input from the video encoding/decoding section 10 is received by the image memory section 9. , but turn off the switch 94 to avoid importing the image data that has become out of synchronization (
Step 4).

If the synchronization recovery of the multiplexing/demultiplexing unit 17 does not end even 10 seconds after the timer starts in step 2, the T3 timer ends and the system control unit 14 receives a T3 timer end (timeout) notification. However, it checks whether or not this notification has been received (step 5).20 If the T3 timer end notification is not received, go to step 6.
When received, the process proceeds to step 10.

When frame synchronization occurs, the multiplexing/demultiplexing unit 17 performs a frame synchronization recovery operation, and when frame synchronization is recovered, the multiplexing/demultiplexing unit 17 notifies the system control unit 14 of frame synchronization recovery, but this notification is controlled by the system. Part 1
4 is received or not is checked in step 5. If the system control unit 14 does not receive the frame synchronization recovery notification, it executes step 5 until it receives the frame synchronization recovery notification. Then, when the system control unit 14 receives the frame synchronization recovery notification,
Step 7) to stop the T3 timer, then switch the input of the single image switching section 93 to the video encoding/decoding section 10,
The received image is displayed on the image display section 8 (Step 8), and then the switch 94 is turned on to start importing the received image into the received image memory 92 (Step 9), and this control ends.

On the other hand, in step 10, when the system control unit 14 receives the T33 timer termination notification in step 5, it switches the input of the image switching unit 93 to the operation screen image memory unit 92. As a result, the image display section 8.

A screen will appear informing the user that a resynchronization procedure has been entered. Then, in the next step 11, the system control section 14 requests the multiplexing/demultiplexing section 17 to start resynchronization, and the multiplexing/demultiplexing section 17 starts the resynchronization procedure. This control ends.

In the above embodiment, the image data of the received image memory section 91 is displayed on the image display section 8 while the T3 timer is activated, but the present invention is not limited to this.
It is also possible to output an image of . In this case, the content displayed on the image display section 8 is that "frame synchronization has occurred and is being recovered." In this embodiment, the received image memory section 9. can be omitted, which has the effect of reducing costs.

In addition, although the above embodiment describes processing when frame synchronization occurs, the present invention can also be applied to processing when an error that causes temporary image disturbance occurs, such as a decoding error in an image codec. Can be applied.

(Effects of the Invention) As described above, according to the multimedia communication device of the present invention, when frame synchronization occurs during image data reception, a distorted image is not displayed.

Furthermore, by displaying the image before frame synchronization occurs during frame synchronization recovery, it is possible to eliminate interruptions in the reception screen before frame synchronization and after frame synchronization is recovered.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a block diagram of a multimedia communication device according to the present invention, and FIG. 2 is a block diagram showing in detail the configuration of a video interface section and the flow of image data in the same device. 3 are flowcharts showing the operating procedure of the apparatus of the present invention. 8... Image display section, 9... Video interface section, 9□... Received image memory section, 9□... Image memory section for operation screen, 93. Image switching section, 94. Switch. Applicant Canon Stock Company Agent Patent Attorney Toshihiko Watanabe

Claims (1)

[Claims] 1. An image display section, a received image memory section that stores a certain amount of received images, an operation screen image memory section that stores an operation screen, and inputting the received image to the received image memory section. a switch for selectively switching between a state in which input is performed and a state in which no input is performed; and a switch for selectively switching between a state in which input is performed and a state in which no input is performed; an image switching section for selecting, when frame synchronization occurs, the still image in the received image memory section is displayed on the image display section while the synchronization is being recovered, and after the frame synchronization is recovered, the received image is changed to the image A multimedia communication device characterized by displaying information on a display unit. 2. The multimedia communication device according to claim 1, wherein the output from the operation screen image memory section is displayed on the image display section if the frame synchronization is not recovered even after a predetermined period of time has elapsed.