JPH0983983A - Video telephone system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video telephone system preventing abnormal stops of extension-decoding processing even when abnormality is generated in data at the time of compression-encoding. SOLUTION: When abnormal data is generated at the time of compression- encoding of picture data by means of the encoding part of a picture codec part 1, an abnormal data form preparing part 18 prepares a data form showing that the abnormality is generated in compressed picture data and transmits it to the video telephone system of an opposite party through a multiplex separation part 14 and a line interface 15. An abnormal data form judging part 19 judges whether picture data received from the video telephone system of the opposite party through the line interface 15 and the multiplex separation part 14 is a form showing abnormal data and when abnormal data is shown, does not give received picture data to a decode buffer 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video telephone apparatus for simultaneously transmitting and receiving image information and audio information via a transmission line under non-procedural data transmission control.

[0002]

2. Description of the Related Art In recent years, a videophone device for transmitting and receiving an image together with a voice has been developed against the backdrop of the sophistication and unified standardization of information communication and image compression techniques. Also in this videophone device, it has become possible to provide recording and reproducing functions by increasing the recording medium density.

A conventional videophone device will be described below. FIG. 9 is a block diagram of a conventional videophone device capable of recording and reproducing. FIG. 9 shows an example in which the communication cable is configured by ISDN, and shows a case where image data and audio data are transmitted to the device of the receiving party.

In FIG. 9, the video codec section 1 includes an encoding section for compressing and coding image data and a decoding section for decompressing and decoding the compressed and coded data. The video codec unit 1 temporarily stores a buffer (hereinafter referred to as an encode buffer) 2 for temporarily storing the image data compressed and encoded by the video codec unit 1 and the compressed image data to be given to the video codec unit 1. A buffer to be stored in (hereinafter, referred to as a decode buffer) 3
Is connected.

A camera 5 for taking a self-portrait is connected to the video codec section 1 via an A / D converter 4.
And the self-portrait decompressed and decoded via the D / A converter 6,
An image display unit 7 for displaying a reproduced image or an image from the device of the communication partner is connected. The A / D converter 4 converts the video signal from the camera 5 into digital data and supplies it as image data to the encoding section of the video codec section 1. The D / A converter 6 converts the image data from the video codec unit 1 into an analog video signal and gives it to the image display unit 7. The encoding unit of the video codec unit 1 compression-encodes the image data from the A / D converter 4 and outputs it to the encode buffer 2 as compressed image data. Further, the decoding section of the video codec section 1 takes in the compression-coded image data from the decoding buffer 3, decompresses it, and gives it to the D / A converter 6.

The voice codec section 10 is connected to a microphone & speaker section 11 including a microphone and a speaker for recording / reproducing or communicating with a communication partner. The audio codec unit 10 compression-encodes the audio data from the microphone, or expands and decodes the compression-encoded audio data, and outputs it to the speaker.

The operation unit 12 is used for inputting a telephone number and selecting functions such as recording and reproduction. The system control unit 13 controls the entire videophone device based on an instruction from the operation unit 12. In addition, the system control unit 1
Reference numeral 3 sends the compressed image data extracted from the encode buffer 2 and the compressed audio data given from the audio codec unit 10 to the image / audio recording medium 17 or the multiplexing / separating unit 14 for communication, or reproduced from the image / audio recording medium 17. The compressed image data and the reproduced compressed audio data are taken out, and the decoding buffer 3 and the audio codec unit 10 are taken out.
Give to.

The demultiplexing unit 14 performs multiplexing for simultaneously transmitting on the line the compressed image data given from the encode buffer 2 and the compressed voice data given from the voice codec unit 10, or receives from the line. The multiplexed compressed image data and compressed audio data are separated. The line interface 15 connects the videophone device to the ISDN network 16 which is a digital transmission line.

Next, the operation of the videophone device shown in FIG. 9 will be described. When the videophone device is set to the recording mode by the operation unit 12, the image data from the camera 5 and the audio data from the microphone of the microphone & speaker unit 11 are given to the video codec unit 1 and the audio codec unit 10, respectively. , Are respectively compression-coded. Both the compressed image data and the compressed audio data that have been compression-encoded are supplied to the demultiplexing unit 14. Demultiplexing unit 14
After multiplexing the compressed image data and the compressed audio data, records the multiplexed compressed image data and the compressed audio data in the image audio recording medium 17, and stores the data.

When the videophone device is set to the reproduction mode by the operation unit 12, the multiplexed compressed image data and compressed audio data are read from the image / audio recording medium 17 and separated by the demultiplexing unit 14. After that, the compressed image data is given to the video codec section 1 via the decode buffer 3, and the compressed audio data is given to the audio codec section 1.
Given to 0. The compressed image data and the compressed audio data are decompressed and decoded by the video codec unit 1 and the audio codec unit 10, respectively, and reproduced by the image display unit 7 and the microphone & speaker unit 11.

When recording the data sent from the other party's device via the line, the operation unit 12 sets the videophone device to the recording mode during communication. As a result, the image data and audio data sent through the line interface 15 are directly transferred to the image / audio recording medium 17.
Recorded in. When playing back the recorded data,
By setting the videophone device to the reproduction mode by the operation unit 12, the image data and the audio data recorded in the image / audio recording medium 17 are read out.

With such a recording / playback function, recording / playback can be performed during non-communication and during communication. Similarly, it is possible to record an answering machine message, reproduce an answering machine message while the answering machine function is being executed, record an answering machine image and voice from the other party, and record an answering machine.

[0013]

In the videophone device capable of recording and reproducing as described above, the video codec section 1
When the data encoded by the encoding unit is returned to the decoding unit side, the data encoded by the encoding unit of the video codec unit 1 is recorded on the video / audio recording medium 17, and the recorded data is reproduced and input to the decoding unit. When the data is encoded by the encoding unit of the video codec unit 1 or is transmitted to the decoding unit of the device of the communication partner through the communication cable, the decoding buffer (FIFO) of the encoding unit is set to the empty state. May be. In such a case, the decoding process is performed when the data is directly input to the decoding unit, when it is input to the decoding unit after recording / reproducing, or when it is input to the decoding unit of the video codec unit 1 of the communication partner device. It may stop abnormally.

Therefore, if the data is not given to the decoding section by the monitor by the CPU (Central Processing Unit) at the time of turning back, an abnormal stop can be avoided. However, at the time of recording or at the time of transmitting data to the device of the communication partner, there is no means for notifying that, and abnormal data is recorded or transmitted as it is. As a result, abnormal data is input to the decoding unit during reproduction or reception, and the decoding process stops abnormally.

It is an object of the present invention to provide a videophone device capable of avoiding an abnormal stop of the decompression decoding process even if a data error occurs during compression encoding.

[0016]

According to a first aspect of the present invention, there is provided a videophone device for compressing image data and an image compressed by the compression device in a videophone device for simultaneously transmitting and receiving image data and audio data. Abnormal when communication means for transmitting data together with voice data and receiving compressed image data together with voice data, decompressing means for decompressing compressed image data, and abnormality in the image data compressed by the compressing means And a determination unit that determines whether or not the image data is abnormal by detecting the abnormality information and that controls access to the decompression unit based on the determination result. It is equipped with.

The videophone device according to the second invention is the first invention.
In the configuration of the videophone device according to the invention, the communication means transmits the abnormality information created by the creating means to another videophone device when the image data is abnormal, and is sent from the other videophone device. The abnormality information is received, and the determination means determines whether or not there is abnormality in the image data by detecting the abnormality information received by the communication means.
The image data is not given to the expansion means when the image data is abnormal.

The videophone device according to the third aspect of the invention is the second aspect.
In the configuration of the videophone device according to the invention, the abnormality information is composed of a plurality of consecutive predetermined codes.

A videophone device according to a fourth aspect of the present invention is the first aspect.
In the configuration of the videophone device according to the invention, the abnormal information created by the creating means at the time of recording is recorded in a recording medium together with the image data and the audio data, and the abnormal information recorded in the recording medium at the time of reproduction is the image data and the audio data. And a recording / reproducing unit for reading together with the determining unit, and the determining unit determines whether or not the image data is abnormal by detecting the abnormality information read by the recording / reproducing unit,
The image data is not given to the expansion means when the image data is abnormal.

The videophone device according to the fifth aspect of the present invention is the fourth aspect.
In the configuration of the videophone device according to the invention, a sync byte, which is an identification information byte for correctly reproducing image data and audio data, is used as abnormality information.

[0021]

In the videophone device according to the first to fifth aspects of the invention, when the image data compressed by the compression means has an abnormality, the abnormality information is generated by the generation means. Also,
Whether or not the image data has an abnormality is determined based on the detection of the abnormality information by the determination means, and access to the expansion means is controlled based on the determination result. Therefore, it is possible to prevent a problem from occurring in the decompression means due to the abnormality in the image data.

In particular, in the videophone device according to the second aspect of the present invention, when an abnormality occurs during the compression of image data, the fact that the image data is abnormal is notified to the receiving side videophone device by the abnormality information. . Further, when it is determined from the abnormality information that the received image data is abnormal, the image data is not given to the expansion means. Therefore, it is possible to prevent the decompression means from abnormally stopping when receiving the data.

Further, in the videophone device according to the fifth aspect of the invention, abnormality information is recorded together with the image data and the sound data when the image data and the sound data are recorded in the recording medium, and the image data and the sound are reproduced when the recording medium is reproduced. Abnormality information is read out together with the data. Therefore,
Based on the abnormality information, it is determined whether or not the image data has an abnormality, and if there is an abnormality, the image data is not given to the expansion means. Therefore, it is possible to prevent the decompression means from abnormally stopping when the data is reproduced.

[0024]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram of a videophone device according to a first embodiment of the present invention. In FIG. 1, parts that are the same as or correspond to those in FIG. 9 are given the same reference numerals, and descriptions thereof will be omitted.

The videophone device of FIG. 1 differs from the videophone device of FIG. 9 in that an abnormal data format creating section 18 and an abnormal data format determining section 19 are further provided. The abnormal data format creation unit 18 creates an abnormal data format according to the state of the encode buffer 2. The abnormal data format determination unit 19 determines whether the compressed image data separated by the demultiplexing unit 14 is in the abnormal data format.

In the present embodiment, the video codec section 1, the encode buffer 2 and the decode buffer 3 form a compression means and an expansion means, and the demultiplexing section 14 and the line interface 15 form a communication means. Further, the abnormal data format creating unit 18 constitutes a creating means, and the abnormal data format judging unit 19 constitutes a judging means.

FIG. 2 is a block diagram of the processing buffers used in the processes of the abnormal data format creation unit 18 and the abnormal data format determination unit 19, respectively.

The processing buffer of FIG. 2 has a processing buffer area B1 consisting of an area of 5 bytes, a push pointer P1 pointing to a byte to be set when setting data in the processing buffer, and should be taken out when extracting data from the processing buffer. It has a pop pointer P2 which points to a byte.
The push pointer P1 is operated so as to always point to the next byte of the processing buffer area B1 after setting the data,
When data is set in the last byte of the processing buffer area B1, the operation is performed so as to point to the first byte of the processing buffer area B1. The pop pointer P2 is operated so as to always point to the next byte after the data is taken out from the processing buffer area B1, and when the data is taken out from the last byte of the processing buffer area B1, the first byte of the processing buffer area B1 is taken. Operated to point.

FIG. 3 is a sequence diagram showing the processing of the abnormal data format creating section 18 in the transmitting side video telephone device. In FIG. 3, the use of the processing buffer of FIG. 2 depends on whether the encode buffer 2 of FIG. 1 is empty or not.
Change of push pointer P1 and pop pointer P2
Shows the flow of changes in 1 byte of data.

FIG. 4 is a sequence diagram showing the processing of the abnormal data format determination unit 19 in the receiving side video telephone device. FIG. 4 shows the flow of the use of the processing buffer of FIG. 2, the change of the push pointer P1 and the change of the pop pointer P2 in 1-byte units of data according to the content of the data from the demultiplexing unit 14 of FIG.

First, the operation of the abnormal data format creating section 18 will be described in detail with reference to FIG. Here, when data is set in or fetched from the byte pointed to by the push pointer P1 or the pop pointer P2 of the processing buffer, each pointer is always the set byte or the preceding byte by the fetched byte. It shall be updated to point. The push pointer P1 and the pop pointer P2 operate similarly thereafter.

At the sequence number s1, if the state of the encode buffer 2 is normal and the push pointer P1 and the pop pointer P2 of the processing buffer point to the same byte, the encoding buffer 2 of the encoding buffer 2 is not accessed. The normal data "n1" is directly used as the transmission image data. Next, in the sequence number s2, when the encode buffer 2 is in the empty state and the push pointer P1 and the pop pointer P2 point to the same byte, all four bytes from the byte pointed to by the push pointer P1 are coded. "FF"
Is set and the code “FF” is used as the transmission image data. Next, in the sequence number s3, if the encode buffer 2 is in the empty state and the push pointer P1 and the pop pointer P2 point to different bytes, the data set in the byte pointed to by the pop pointer P2, In this case, the code "FF" is used as the transmission image data.

Next, at the sequence number s4, the push pointer P indicating that the encoding buffer 2 is normal
1 and the pop pointer P2 point to different bytes, the normal data "n" in the encode buffer 2
2 "is set to the byte of the processing buffer pointed to by the push pointer P1, and the data set to the byte pointed to by the pop pointer P2, in this case, the code" FF "is set as the transmission image data. Since the sequence number s5 has the same condition as the sequence number s4, the processing buffer is similarly accessed and the transmission image data is set to the code "FF". Sequence number s
Since the condition is the same as that of No. 3, the same access as that of the sequence number s3 is performed, and in this case also, the transmission image data is set to the code “FF”.

Next, since the sequence number s7 has the same conditions as the above-mentioned sequence numbers s4 and s5, access is performed in the same manner as the sequence numbers s4 and s5, and the byte pointed by the pop pointer P2 is set. The data “n2” that has been set is the transmission image data.
Next, in the sequence number s8, the conditions are the same as those of the above sequence numbers s4, s5, s7, so access is performed in the same manner as the sequence numbers s4, s5, s7. In this case, the pop pointer P2 indicates The data “n3” set in the specified byte is the transmission image data. Next, in the sequence numbers s9 and s10, since the conditions are the same as those in the sequence numbers s3 and s6, the transmission image data are "n4" and "n5", respectively.
Becomes

Next, in the sequence number s11,
Since the condition is the same as that of the sequence number s1, the transmission image data is set to "n6" without accessing the processing buffer. The abnormal data format can be created by performing the respective processing under the conditions that match the above sequence.

Next, the operation of the abnormal data format determination unit 19 will be described in detail with reference to FIG. First, the sequence number s
11, the received image data is normal data “n1”
And the push pointer P1 and the pop pointer P2 of the processing buffer point to the same byte, the data "n1" is given to the decoding buffer 3 without accessing the processing buffer. Next, in the sequence number s12, the received image data has the code “FF”. This means that it is an abnormal data format in which four codes "FF" follow, or normal data but the data value happens to be the code "FF". In this case, since the push pointer P1 and the pop pointer P2 point to the same byte, the received image data code "F" is set in the byte pointed to by the push pointer P1.
F "is set and no data is given to the decode buffer 3. Next, at sequence number s13, the received image data has the code" FF "and the push pointer P1.
If the pop pointer P2 points to a different byte, the same access as the sequence number s12 is performed, and no data is given to the decode buffer 3. Next, also in the sequence number s14, the same access as in the sequence number s13 is performed, and the decoding buffer 3
To give no data. Next, also in the sequence number s15, the same access as in the sequence numbers s13 and s14 is performed, and no data is given to the decode buffer 3.

Next, at the sequence number s16, since four codes "FF" have already been set in the processing buffer in succession, the data format can be discriminated together with the code "FF" of the received image data. it can. Therefore, no data is given to the decode buffer 3 and the bytes pointed by the push pointer P1 and the pop pointer P2 are matched. In the sequence number s17, similarly to the sequence number s11, the received image data “n2” is given to the decode buffer 3 without accessing the processing buffer.

Next, in the sequence number s18,
Since the received image data has the code "FF" and the push pointer P1 and the pop pointer P2 point to the same byte, the code "FF" of the received image data is assigned to the byte pointed to by the push pointer P1 as in the sequence number s12. It is set and no data is given to the decode buffer 3. Next, in the sequence number s19, since the received image data is normal and the push pointer P1 and the pop pointer P2 point to different bytes, the received image data “n4” is set to the byte pointed to by the push pointer P1. , The code "FF" extracted from the byte pointed to by the pop pointer P2 is given to the decode buffer 3 as normal data. next,
In the sequence number s20, the received image data has the code “FF” and the push pointer P1 and the pop pointer P2 do not point to the same byte, but the data set in the processing buffer immediately before is the code “FF”.
Therefore, the code "FF" of the received image data is set in the byte pointed by the push pointer P1, and the data "n4" is taken out from the byte pointed by the pop pointer P2 and given to the decode buffer 3.

Next, the sequence numbers s21, s22, s
23, the above sequence numbers s13, s1
4, the same processing as s15 is performed. Sequence number s24
In, the same processing as the above sequence number s17 is performed. The abnormal data format can be determined by performing the respective processing under the conditions that match the above sequence.

Since the abnormal data format creating section 18 in the transmitting side video telephone apparatus and the abnormal data format determining section 19 in the receiving side video telephone apparatus do not input abnormal data to the decoding section, the video codec section 1
Does not stop abnormally. In addition, the audio data can be reproduced without interruption by inputting the audio data to the audio codec unit 10 regardless of whether the sync is abnormal or normal.

As described above, when the encoding buffer 2 in the transmitting side video telephone device is in the empty state, the abnormal data format creating section 18 transmits the fact to the other party's video telephone device. Five consecutive codes "FF" that do not normally appear are transmitted to the other party's videophone device as an abnormal data format. In the videophone device on the receiving side, the abnormal data format determination unit 19
Determines whether the received data is in the abnormal data format, and if it is in the abnormal data format, controls access so that the data is not given to the decode buffer 3.

In such a control system, a transmission delay of image data of a maximum of 4 data units occurs, but such a delay with respect to audio data is completely problematic as compared with the delay due to the image compression and expansion processing time. I won't. Therefore, even when the encode buffer 3 is in the empty state, it can be notified to the videophone device of the communication partner, and the decoding process in the videophone device of the receiving side can be prevented from abnormally stopping. .

FIG. 5 is a block diagram of a videophone device according to the second embodiment of the present invention. 5, parts that are the same as or correspond to those in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted. In the videophone device of FIG. 5, the image / audio recording medium 1
7 is composed of a mini disk.

The image / audio recording medium 17 includes a mini disk interface section 20 and a mini disk section 21. The configuration of the other parts is the same as that of the videophone device of FIG. 1, and thus the description thereof is omitted.

In this embodiment, the video / audio recording medium 17 constitutes recording / reproducing means. FIG. 6 is a block diagram showing a detailed structure of the mini disk interface section 20 and related parts. Mini disk interface section 20
Includes a sync byte control circuit 22, a FIFO 23, and an interface control unit 24. The sync byte control circuit 22 adds a sync byte to the beginning of the data in order to synchronize the image data and the audio data. FIFO
23 outputs first the data inputted first. The interface control circuit 24 controls the timing of writing and reading of data.

When the compressed image data and the compressed audio data are recorded on the mini disk, the abnormal data format creating section 18 outputs an identification signal indicating whether or not the encode buffer 2 is in the empty state. Also, the demultiplexing unit 14 gives the compression-coded data to the sync byte control circuit 22 at the communication transfer rate. The sync byte control circuit 22 adds a normal sync byte or an abnormal sync byte to the data based on the identification signal output from the abnormal data format creation unit 18, and adds a compressed image data sequence and compressed audio with the sync byte. Form a data series. Then, the sync byte control circuit 22 writes the compressed image data series and the compressed audio data series into the FIFO 23 for absorbing the data transfer rate and the minidisk transfer rate. And the FIFO 23
The data output from the interface control circuit 24
The data is recorded on the mini disk unit 21 via.

FIG. 7 is a configuration diagram of a recording format in the second embodiment of the present invention. FIG. 8 is a flowchart showing the operation of the sync byte control circuit 22.

Here, the interface processing in the mini disk interface section 20 will be described with reference to FIGS. 7 and 8. Here, assuming that the communication speed of the compressed image data is 128 kbps, the access speed of the mini disk is 300 kbps on average, and therefore the recording format shown in FIG. 7 is used in order to perform speed control and distinguish between normal time and abnormal time. Make a record.

First, at the time of recording, it is determined whether or not the half flag of the FIFO 23 is on (step S).
1). If the half flag is on, the code "FF" is written on the mini disk (step S2). On the other hand, when the half flag is off, the abnormal data format creation unit 1
Whether the data is abnormal data is determined based on whether the identification signal 8 is on or off (step S3). When the identification signal of the abnormal data format creation unit 18 is ON,
For example, "A" is written on the mini disk as a sync character when data is abnormal (step S4). When the identification signal of the abnormal data format creation unit 18 is off, for example, "B" is written on the mini disk as the sync character when the data is normal (step S5).

Then, the audio data is written to the mini disk (step S6), the image data is written (step S7), and the same sync character as in step S4 or S5 is written to the mini disk (steps S8, S).
9).

At the time of reproduction, the data is read from the mini disk, and the abnormal data format determination unit 19 determines the sync character.
The image data is transferred to the decode buffer 3 when not normal.

As described above, since no abnormal data is input to the decoding section of the video codec section 1, the video codec section 1 does not stop abnormally. In addition, the audio data can be reproduced without interruption by inputting the audio data to the audio codec unit 10 regardless of whether the sync is abnormal or normal.

As described above, when recording / reproducing to / from the mini disc, when the encode buffer 2 is in the empty state, in order to notify the mini disc to that effect, image data and audio data are transmitted. The sync byte to be added for synchronization is added as a sync byte different from the normal one. At the time of reproduction, the abnormal data format determination unit 19 determines whether the sync byte of the reproduced data is the abnormal sync byte or the normal sync byte, and when the abnormal data sync byte is the abnormal sync byte, No image data is transferred to the decode buffer 3.

In the videophone devices of the first and second embodiments described above, abnormal data is generated regardless of the state of the encoding unit of the video codec unit 1 mainly by software processing by the CPU (central processing unit). It can be prevented from being given to the decoding section of the video codec section 1. Therefore, a system saving and a low-cost videophone device can be realized.

[0055]

As described above, according to the first to fifth aspects of the present invention, even if an abnormality occurs in the image data when the image data is compressed, the decompression means is prevented from abnormally stopping.

[Brief description of drawings]

FIG. 1 is a block diagram of a videophone device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of processing buffers used in processing of an abnormal data format creation unit and an abnormal data format determination unit, respectively.

FIG. 3 is a sequence diagram showing processing of an abnormal data format creation unit in the videophone device on the transmission side.

FIG. 4 is a sequence diagram showing processing of an abnormal data format determination unit in the receiving side video telephone device.

FIG. 5 is a block diagram of a videophone device according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a detailed configuration of a mini disk interface section and related portions.

FIG. 7 is a configuration diagram of a recording format in a second embodiment of the present invention.

FIG. 8 is a flowchart showing the operation of the sync byte control circuit.

FIG. 9 is a block diagram of a conventional videophone device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Video codec section 2 Encode buffer 3 Decode buffer 4 A / D converter 5 Camera 6 D / A converter 7 Image display section 10 Audio codec section 11 Microphone & speaker section 12 Operation section 13 System control section 14 Multiplexing / separating section 15 Line interface 16 ISDN network 17 Video / audio recording medium 18 Abnormal data format creation unit 19 Abnormal data format determination unit 20 Mini disk interface unit 21 Mini disk unit 22 Sync byte control circuit 23 FIFO 24 Interface control circuit B1 Processing buffer area P1 Push pointer P2 Pop pointer

Claims (5)

[Claims] 1. In a videophone apparatus for simultaneously transmitting and receiving image data and audio data, a compression means for compressing the image data, and image data compressed by the compression means are transmitted together with the audio data and compressed. A communication unit that receives the voice data, a decompression unit that decompresses the compressed image data, and a predetermined abnormality information that indicates that the image data compressed by the compression unit has an abnormality. And a determination unit that determines whether or not there is an abnormality in the image data by detecting abnormality information and that controls access to the decompression unit based on the determination result. apparatus. 2. The communication means transmits the abnormality information created by the creating means to another videophone device and receives the abnormality information sent from the other videophone device, and the determination means comprises: It is determined whether or not there is an abnormality in the image data by detecting the abnormality information received by the communication means, and when the image data has an abnormality, the image data is not given to the decompression means. The videophone device according to item 1. 3. The videophone device according to claim 2, wherein the abnormality information is composed of a plurality of consecutive predetermined codes. 4. A recording / reproducing process for recording abnormality information created by the creating means together with image data and audio data on a recording medium at the time of recording, and reading out the abnormal information recorded on the recording medium together with image data and audio data during reproduction. Further, the determining means determines whether or not the image data is abnormal by detecting the abnormality information read by the recording / reproducing means, and when the image data is abnormal, the decompressing means is provided. The videophone device according to claim 1, wherein image data is not given to the videophone device. 5. The videophone device according to claim 4, wherein a sync byte, which is an identification information byte for correctly reproducing image data and audio data, is used as the abnormality information.