JPH10234045A - Time-varying image communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the time-varying image communication equipment in which a delay of transmission is prevented by suppressing increased capacity of a standby buffer due to a long re-transmission wait time, lot of code bit amount is assigned to realize improved image quality and a coded type is accurately detected. SOLUTION: A time-varying image decoder 100 is provided with a coding type detection section 112 that detects a coding type, a reference image discrimination section 113 that discriminates whether or not the data received in error based on the coded type are a reference image of data correctly received, and a re-transmission request discrimination section 110 that discriminates whether or not a retransmission request is made based on an output of the reference image discrimination section 113. Then the reference image discrimination section 113 discriminates whether or not erroneous image data are a reference image of succeeding image, and when the data are used for the reference image, since it gives effects on the succeeding image, re-transmission request is made. When the data are not used for the reference image, since it gives no effects on the succeeding image, no re-transmission request is made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving image communication apparatus for moving image compression, and more particularly, to a moving image communication apparatus used in a communication path having an error, and more particularly, to an AR apparatus for correcting an error.
The present invention relates to a moving image communication device performed by a method called Q (Automatic Repeat Request).

[0002]

2. Description of the Related Art JPEG (Jo
int Photograghic Expert Group) or MPEG (Moving
Picture Expert Group).

[0003] MPEG is characterized by DCT (Discrete Cos
ine Transform: Performs inter-frame prediction processing for compression in the time axis direction in addition to still image compression by discrete cosine transform. As prerequisites for moving image compression, it is mentioned that random access to frames can be performed, and reproduction by fast forward and rewind reproduction (reverse direction) can be performed.

In MPEG, fast forward, rewind,
Since playback from the middle is fundamental, moving pictures of a certain unit are collectively formed to form a GOP (Group of Pictures) so that independent playback can be performed in that unit. As a predictive structure of a screen in the GOP, individual pictures (pictures), I, B, and P pictures, which mean frames of a moving image, are used.

[0005] The pictures are classified into the following types according to the encoding method.

(1) I-picture (Intra-coded picture) When coding, only closed information in one picture is used. In other words, when decoding, an image can be reconstructed using only the information of the I picture itself. In practice, DCT is coded without any difference from other images. Although this encoding method is generally inefficient, random insertion and high-speed reproduction can be achieved by decoding the I picture only by putting it anywhere. Further, if the I picture is decoded, stored in the memory, and read in the reverse direction, reverse reproduction can be performed.

(2) P picture (Predictive-coded pictur)
e: forward prediction coded image) P picture is a prediction image (a reference image for taking a difference)
Use an I-picture or a P-picture which is located earlier in time at the input and has already been decoded. In practice, it is possible to select, on a macroblock-by-macroblock basis, whether to encode the difference from the motion-compensated predicted image or to encode without taking the difference (intra encoding).

(3) B picture (Bidirectionally predict
ive-coded picture: bidirectional predictive coded image) A B picture is a temporally preceding I-picture or P-picture that is located earlier in time as a predicted picture, and an already-decoded I-picture or P-picture that is located later in time. , And interpolated images made from both. Here, in the case of an interpolation frame, prediction is performed from both directions, but there are three types of motion compensation prediction modes which are roughly classified. These are forward motion compensation for predicting the present from the past, backward motion compensation for predicting the present from the future, and interpolation motion compensation for predicting the present from both the past and the future. The forward motion compensation and the backward motion compensation are the same processes as ordinary motion compensation (MC) in that matching is performed with a block read from one reference frame. In addition, the interpolation motion compensation is to obtain a prediction signal by combining blocks read from two reference frames by weighting in consideration of the time distance between the current frame and the reference frame.

The most efficient one of the three types of difference coding and intra coding after motion compensation can be selected for each macroblock.

[0010] In order to encode or decode a B picture in a GOP, an I picture or a P picture which is a temporally backward prediction picture must be coded first. A predetermined order is necessary for the I picture, the P picture, and the B picture in order to construct the formula. However, the interval between the I pictures and the interval between the P pictures are free and may be changed inside the GOP.

As a conventional moving picture decoding apparatus of this type,
For example, there is one disclosed in Japanese Patent Application No. 7-98645 “Moving image data transmission device”.

As described in the above publication, "intra-frame encoding", "inter-frame encoding", and "bidirectional encoding" are performed as a method of encoding a moving image, and the data and encoding are performed. In the type communication device, when an error occurs, a retransmission request is made only for an "intra-coded" frame.

In order to reliably transmit correct data in an erroneous environment, a method called ARQ (Automatic Repeat Request) may be used. ARQ is realized by error detection and data retransmission. On the transmitting side, data to be transmitted (encoded bit string) is divided into units called frames, and CRC (Cyclic Redundancy Check) is performed in frame units.
k: Cyclic redundancy check code) and an error detection code and a frame number are transmitted. The receiving side checks whether or not the received frame has an error using the error detection code. If there is no error, the data is passed to the processing unit. If there is an error, the frame number is notified to the transmission measurement and a request is made to transmit the same frame again. The transmitting side transmits a retransmission request (A
RQ signal), and transmits the same frame again. With such a mechanism, data can be transmitted accurately even on an erroneous transmission path.

FIG. 7 is a block diagram showing the configuration of a conventional moving picture decoding apparatus having a ΑRQ function. In the figure, a solid line indicates a data flow, and a broken line indicates a control signal.

In FIG. 7, a moving picture decoding apparatus includes a multiplexed bit stream input terminal 101 to which a multiplexed signal is input, a multiplexed bit stream receiving buffer 102 for storing the input multiplexed bit stream signal, and a separation of the multiplexed signal. And a system multiplex decoder 103 for dividing the signals into signals of respective media, and a standby buffer 1 for holding a separated signal (here, only an image).
05, a data write control unit 104 for controlling whether data is written to the samurai machine buffer 105, a video decoding unit 107 for decoding input image data, an output of the system multiplex decoder 103 and an output of the standby buffer 105 A selector 106 for switching which is input to the video decoding unit 107, a data input control unit 109 for controlling the selector 106, an image signal output terminal 108 for outputting the result of the video decoding unit 107, and whether to issue a retransmission request , A retransmission request output terminal 111 that outputs a retransmission request signal, and an encoding type detection unit 112 that detects the encoding type of the input image data.

In the moving picture decoding apparatus, a retransmission request determining unit 110 and a retransmission request output terminal 111 are added to a normal moving picture decoding apparatus for an ARQ function.

In the above configuration, the coding type detected by the coding type detecting section 112, the SN (Sequence Number) output from the system multiplex decoder 113, and C
The result of the RC code check is input to the retransmission request determination unit 110, and if the result of the CRC check is an error, that is, if the data is erroneous, the coding type is “intra-frame coding”.
If so, a retransmission request signal is output from the retransmission request signal output terminal 111 together with the SN.

[0018]

However, it has been found that such a conventional moving picture decoding apparatus having an ARQ function has the following problems when a retransmission request is made by the above method.

That is, the coding efficiency is reduced when the "intra-frame coded" image is not the reference image of the next image.

Also, an image subjected to "inter-frame encoding" may be used as a reference image for the next image. In this case, the image quality is degraded unless a retransmission request is made.

Further, since the coding type may be incorrect, the coding type cannot be specified correctly from the frame having the error, and correct control cannot be performed at that time.

The present invention suppresses an increase in the waiting buffer due to a long retransmission waiting time, prevents delay, improves the image quality by allocating a large amount of coding bits, and accurately detects the coding type. It is an object of the present invention to provide a moving image communication device capable of performing the above.

[0023]

SUMMARY OF THE INVENTION A moving picture communication apparatus according to the present invention is a moving picture communication apparatus having a function of retransmitting when input data has an error. And a reference image determining means for determining whether or not the erroneously received data is a reference image of the correctly received data based on the encoding type information, and a retransmission request based on the output of the reference image determining means And a retransmission request judging means for judging whether the retransmission is required.

The above moving picture communication apparatus comprises a sequence number storing means for storing a sequence number, and an error storing means for storing an error processing result, and the reference image judging means detects an error based on the sequence number and the error processing result. It may be determined whether or not the received data is a reference image of the data received correctly one time later.

The above moving picture communication apparatus comprises a sequence number storing means for storing a plurality of sequence numbers, and an error storing means for storing a plurality of error processing results, wherein the reference image determining means includes a plurality of sequence numbers and a plurality of error numbers. Based on the processing result, it may be determined whether or not the erroneously received data is a reference image of the data received correctly before and after.

The moving image communication apparatus may include moving image decoding means for decoding moving image data, and decode the moving image data after the reference image is determined by the reference image determining means.

The encoding type detection means may output the encoding type detected when decoding the image data as encoding type detection information.

Further, the moving picture communication apparatus may include ARQ (Automatic Repeat Request) control means for accurately transferring data on a communication path having an error by detecting an error and retransmitting the data. The encoding is MPE
G (Moving Picture Expert Group) coding scheme or H.264 H.261 or the like.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A moving picture communication apparatus according to the present invention comprises:
The present invention can be applied to a moving picture decoding apparatus having an ARQ function for accurately transferring data on a communication path having an error by error detection and data retransmission.

FIG. 1 shows ΔR according to the first embodiment of the present invention.
It is a block diagram which shows the structure of the moving image decoding apparatus which has a Q function. In the description of the video decoding device according to the present embodiment, the same components as those of the video decoding device shown in FIG. 7 are denoted by the same reference numerals.

In FIG. 1, reference numeral 100 denotes a video decoding device (video communication device) having a ΑRQ function. The video decoding device 100 has a multiplexed bit string input terminal 101 to which a multiplexed signal is input, A multiplexed bit stream receiving buffer 102 for storing a multiplexed bit stream, a system multiplex decoder 103 for separating a multiplexed signal and dividing it into signals for each medium, a standby buffer 105 for waiting for a separated signal (here, only an image); Data write control unit 1 for controlling whether to write data to samurai machine buffer 105
04, moving image decoding unit 1 for decoding input image data
07 (moving image decoding means), a selector 106 for switching which of the output of the system multiplex decoder 103 and the output of the standby buffer 105 is input to the moving image decoding unit 107, a data input control unit 109 for controlling the selector 106, Image signal output terminal 10 for outputting the result of moving image decoding section 107
8. Retransmission request determination unit 110 (retransmission request determination unit) for determining whether to issue a retransmission request, retransmission request output terminal 111 for outputting a retransmission request signal, encoding type for detecting the encoding type of input image data It comprises a detecting unit 112 (encoding type detecting unit) and a reference image determining unit 113 (reference image determining unit) for determining whether or not the image is a reference image.

The system multiplex decoder 103 has a function as a sequence number storing means for storing a sequence number and an error storing means for storing an error processing result.

The reference image judging section 113 judges whether or not erroneous image data becomes a reference image of a subsequent image. If the erroneous image data is a reference image as described later with reference to FIG. Therefore, a retransmission request is made, and if it is not a reference image, a process is performed in which a retransmission request is not made since the subsequent image is not affected.

As described above, the moving picture decoding apparatus 100 according to the present embodiment has a configuration in which the reference picture judging section 113 is added to the moving picture decoding apparatus shown in FIG.

Next, the operation of the moving picture decoding apparatus 100 configured as described above will be described.

FIG. 2 is a flowchart for explaining the operation of the reference image determining unit 113. In the figure, ST indicates each step of the flow.

Referring to FIG. 2, this flow includes the following steps. That is, a step ST101 of acquiring an encoding type, a step ST102 of determining whether or not a previous frame is used as a reference image, a step ST103 of outputting a result as a reference image, and a step of outputting a result of not using a reference image ST104, SN (Sequ
Step ST105 for storing the previous SN, Step ST106 for outputting the previous SN, and CRC (Cyclic).
(Redundancy Check) Step ST107 for storing the result of the check, and step ST108 for outputting the result of the previous CRC check.

The detailed operation will be described below with reference to the flowcharts shown in FIGS.

As shown in FIG. 1, first, a multiplexed bit string that has passed through a transmission path is input from a multiplexed bit string input terminal 101. The input bit sequence is input to the multiplexed bit sequence receiving buffer 102, and the system multiplex decoder 10
It is read in accordance with the timing of 3.

The system multiplex decoder 103 separates the input signal into multiplexed signals and divides them into signals of each medium.

Here, the CRC of the divided signal is checked, and if there is no error, it is determined whether a retransmission request is currently made. If the retransmission request is made, the currently acquired data has made a retransmission request. Then, if the acquired data has been requested to be retransmitted, the acquired data is input to the video decoding unit 107.

It is determined whether or not the currently acquired data is a signal indicating that the retransmitted data cannot be retransmitted unless the data has been requested to be retransmitted. The data before the data for which the data retransmission request is determined is input to the video decoding unit 107 via the selector 106.

In other cases, data is input to the standby buffer 105.

The encoding type detecting section 112 detects the encoding type of the input data, and inputs the result to the reference image determining section 113.

Regarding the operation of the reference image determining unit 113,
This will be described with reference to FIG.

First, an encoding type is obtained in step ST101. Next, in step ST102, it is determined whether or not the image data of the previous frame is a reference image of the image data just acquired using the encoding type information.
If it is to be a reference image, a result indicating that it is a reference image is output in step ST103, and the process proceeds to step ST105. If it is not a reference image, a result indicating that it is not a reference image is output in step ST104, and step ST10 is performed.
Go to 5.

For example, if the encoding type is "intra-frame encoding", it is understood that the image data of one frame before is not referred to. Also, in the case of “inter-frame coding”, it can be understood that the image data of one frame before is referred to. Also, it can be seen that there is a possibility that the image data of one frame before is also referred to in the case of “bidirectional predictive coding”.

In step ST105, one of the outputs of the system multiplex decoder 103 is SN (Sequence Number).
r) is stored, and the immediately preceding SN (shown as SN-1 in FIG. 1) is output from the SN just obtained in step ST106.

Next, in step ST107, the result of the CRC check, which is one of the outputs of the system multiplex decoder 103, is stored. In step ST108, the result of the CRC check immediately before the result of the CRC check just obtained (FIG. 1) In this case, it is output as CRCresult-1), and the flow ends.

Returning to FIG. 1, the above three outputs, that is, the discrimination signal (RI in FIG. 1) for determining whether or not the image is a reference image, SN-1 and CRCresult-1 are input to the retransmission request determination section 110, and the retransmission request Make a decision.

The retransmission request judging section 110 judges a retransmission request, and if it is necessary to make a retransmission request (for example, if the previous image data is a reference image of the image data just acquired, If the result is an error), a retransmission request signal (FIG. 1) together with the immediately preceding S (SN-1 in FIG. 1).
ARQ request) to the retransmission request signal output terminal 11
Output from 1. Thereafter, the result is notified to the system multiplex decoder 103.

On the other hand, if retransmission request determining section 110 determines that there is no need to request a retransmission, it is determined whether a retransmission request is currently made.
Is input to the video decoding unit 107 via the selector 106 before the data for which the data retransmission request is determined.
This processing is performed by the retransmission request determination unit 110 by the data input control unit 1.
The control signal is transmitted to the data input control section 09, and the data input control section 109 controls the selector 106 to realize the control.

After the above processing is performed, the moving image decoding unit 1
At 07, the input image data is decoded, and the decoded image data is output from the image signal output terminal 108.

As described above, the moving picture decoding apparatus 100 according to the first embodiment uses the coding type detection unit 112 for detecting the coding type and the data received erroneously based on the coding type. Reference image determination unit 113 that determines whether or not the received data is a reference image
And a retransmission request determination unit 110 that determines whether to request retransmission based on the output of the reference image determination unit 113. The reference image determination unit 113 determines whether the incorrect image data is a reference image of a subsequent image. It is determined whether the image is a reference image, and if the image is not a reference image, a retransmission request is performed. If the image is not a reference image, a retransmission request is not performed because the image is not affected. Since it is configured as described above, retransmission is not performed more than necessary, suppressing the increase of the standby buffer due to long retransmission waiting time and preventing delay,
In addition, a large amount of coded bits can be allocated, and the image quality can be improved. Further, since the encoding type is detected from the correctly received data, the encoding type can be correctly determined.

On the other hand, it can be used even when the encoding type is not known in advance, such as a stored image,
When real-time performance is important (for example, TV
Phone, etc.).

In the present embodiment, the coding type detecting unit 112 for detecting the coding type for determining whether or not the erroneous two-image data is the later reference image is provided before the moving image decoding unit 107. However, it is also possible to use the encoding type detected at the time of image decoding.

In this embodiment, S is set for each frame.
Although an example in which N is added has been shown, for example, even when one frame is divided into units of GOB (Grop of Blocks), by detecting the encoding type of the image after one frame, the reference image is similarly set. You can see if it is.

FIG. 3 shows ΔR according to the second embodiment of the present invention.
Reference image determination unit 113 of video decoding device having Q function
6 is a flowchart showing the operation of the first embodiment. The overall configuration of the video decoding device according to the present embodiment is the same as that in FIG. 1 described above, and only the operation of the reference image determination unit 113 is different.

In FIG. 3, the operation flow of the reference image judging section of the present moving picture decoding apparatus comprises the following steps. That is, step ST2 of acquiring an encoding type
01, step ST2 for storing the obtained encoding type
02, step ST203 of acquiring the coding type before and after the data to be determined, step ST203 of determining whether the preceding and succeeding frames use the data to be determined as a reference image
204, Step S for outputting a result as a reference image
T205, step ST206 of outputting a result indicating that the image is not a reference image, step ST207 of storing SN, step ST208 of outputting the SN of data to be determined,
Step ST20 for storing the result of the CRC check
9. Step ST210 of outputting the result of the CRC check of the data to be judged. Note that the data to be determined is data that is to be determined as to whether or not it is a reference image of a previous or next frame.

The operation of the reference image determining section will be described below with reference to the flowchart shown in FIG.

First, the coding type is obtained in step ST201, and the obtained coding type is stored in step ST202. Next, in step ST203, the encoding types before and after the data to be determined are obtained, and in step ST2.
In step 04, it is determined whether or not the data to be determined is a reference image of a frame before and after that using the information. If the image is to be a reference image, a result indicating that the image is a reference image is output in step ST205, and the process proceeds to step ST207.
If the image is not a reference image, a result indicating that the image is not a reference image is output in step ST206, and the process proceeds to step ST207.

An example of the above determination method will be described with reference to FIG.

FIG. 4 is a block diagram showing an example of reference image determination. In the figure, I,..., And B represent frames subjected to intra-frame coding, inter-frame coding, and bidirectional predictive coding, respectively.

For example, when the data to be determined is the data of the three frames in FIG.
Suppose that the coding type of two or four frames has been acquired. In the first embodiment, since the fourth frame after the third frame is intra-coded, no retransmission request is made because the fourth frame does not become a reference image of a subsequent image. It is determined that the image that has been bidirectionally coded is a reference image (can be a reference image).

As a result, the third frame is requested to be retransmitted.

As another example, when the sixth frame is the data to be determined, for example, it is assumed that the coding types of the fourth, fifth, seventh, and eighth frames have been acquired. Although the sixth frame is a reference image of the seventh frame, the eighth frame is intra-frame coded data, so that a retransmission request is not issued.

Next, in step ST207, one of the outputs of the system multiplex decoder 103 is stored, and in step ST208, the SN of the data to be determined is output.
Next, in step ST209, the system multiplex decoder 10
And stores the result of the CRC check, one of the outputs of
In step ST210, the result of the CRC check of the data to be determined is output, and this flow ends.

As described above, in the moving picture decoding apparatus according to the second embodiment, the reference picture judging section not only determines whether the erroneous picture data is a reference picture of a succeeding picture but also refers to a reference picture of a preceding picture. Since a function of determining whether or not the image is an image is provided, it is possible to more accurately determine whether or not the image is a reference image, and it is possible to particularly prevent frame skipping of a previous image.

FIG. 5 shows ΔR according to the third embodiment of the present invention.
It is a block diagram which shows the structure of the moving image decoding apparatus which has a Q function. In the description of the video decoding device according to the present embodiment, the same components as those in FIG. 1 are denoted by the same reference numerals.

In FIG. 5, reference numeral 200 denotes a video decoding device (video communication device) having a ΑRQ function. The video decoding device 200 receives a multiplexed bit string input terminal 101 to which a multiplexed signal is input, A multiplexed bit stream receiving buffer 102 for storing a multiplexed bit stream, a system multiplex decoder 103 for separating a multiplexed signal and dividing it into signals for each medium, a standby buffer 105 for waiting for a separated signal (here, only an image); Data write control unit 1 for controlling whether to write data to samurai machine buffer 105
04, moving image decoding unit 1 for decoding input image data
07, a selector 106 for switching which of the output of the system multiplex decoder 103 and the output of the standby buffer 105 is input to the video decoding unit 107, a data input control unit 109 for controlling the selector 106, An image signal output terminal 108 for outputting a result, a retransmission request determination unit 110 for determining whether to issue a retransmission request, a retransmission request output terminal 111 for outputting a retransmission request signal, and an encoding type input for inputting an encoding type of image data. It comprises a terminal 201 (encoding type detecting means) and a reference image determining unit 202 (reference image determining means) for determining whether or not the image is a reference image.

The configuration of the third embodiment includes an encoding type input terminal 201 and a reference image judging unit 202 which operates differently from the reference image judging unit 113 of FIG. The difference from the first embodiment is that the conversion type detection unit 112 is not provided.

The operation of the moving picture decoding apparatus 200 configured as described above will be described below.

The basic operation is almost the same as the operation described in the first embodiment. However, since the third embodiment is an example in which the encoding type is known in advance, the encoding type input terminal From 201, the encoding type of the data obtained at present is input to the reference image determination unit 202, and it is determined whether the data is a reference image.

For example, an example of reference image determination is shown in FIG.
(B). In the example of FIG. 6A, the second frame is data that has been bidirectionally predictively coded, and it is determined that the second frame does not become a reference image of any of the preceding and following images.
Also, taking the example of FIG. 6B, this indicates that the subsequent frames are encoded with reference to the intra-coded 0th frame. At this time, it is determined that the second frame does not become a reference image of any of the preceding and following images. FIG.
Since the two examples (a) and (b) are also determined not to be reference images, no retransmission request is made.

The operation other than the above-described reference image determination is the same as the operation described in the first embodiment.

As described above, the moving picture decoding apparatus 200 according to the third embodiment has the
Reference image determination unit 202 by inputting the encoding type from 1
However, since it is configured to use an encoding type that is known in advance, it is possible to immediately determine whether or not erroneous image data is a reference image of the preceding and following images, a delay before requesting retransmission. Can be prevented.

Therefore, the moving picture communication apparatus having the above-mentioned excellent features is suitably applied to, for example, a moving picture decoding apparatus conforming to the $ PEG2 system. As the ΜPEG system, a system in which a movie or a TV program is converted into a ΜPEG stream can be considered.

In each of the above embodiments, the moving picture decoding apparatus may be applied to a moving picture compression apparatus based on, for example, the MPEG algorithm. However, the present invention is not limited to this. Needless to say, it can be applied to all devices.

Further, it goes without saying that the number and types of circuits, buffers, and selectors constituting the moving picture decoding apparatus, the reference picture judging section, and the details of the processing steps are not limited to those of the above-described embodiments. It may be realized by software.

Further, in each of the above embodiments, the present invention is applied to a moving picture decoding apparatus. However, any apparatus that adaptively switches retransmission requests may be used. It is not something to be done. As long as it is within the scope of the technical idea of the present invention, it can be appropriately changed like a moving image processing device or the like, and may be a mode incorporated in a part of the moving image device.

[0081]

According to the moving picture communication apparatus of the present invention, the coding type detecting means for detecting the coding type and the erroneously received data based on the coding type information become the reference image of the correctly received data. The retransmission request determination means for determining whether or not to request retransmission based on the output of the reference image determination means. , The delay can be prevented, the image quality can be improved by allocating a large amount of encoded bits, and the encoding type can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a moving image communication device according to a first embodiment to which the present invention has been applied.

FIG. 2 is a flowchart illustrating an operation of a reference image determining unit of the moving image communication device.

FIG. 3 is a flowchart illustrating an operation of a reference image determining unit of the moving image communication device according to the second embodiment to which the present invention is applied.

FIG. 4 is a diagram for explaining a reference image determination example of the moving image communication device.

FIG. 5 is a block diagram illustrating a configuration of a moving image communication device according to a third embodiment to which the present invention has been applied.

FIG. 6 is a diagram for explaining a reference image determination example of the moving image communication device.

FIG. 7 is a block diagram illustrating a configuration of a conventional video decoding device.

[Explanation of symbols]

100, 200 video decoding device (video communication device),
101 multiplexed bit string input terminal, 102 multiplexed bit string reception buffer, 103 system multiplex decoder, 10
4 data write control unit, 105 standby buffer, 10
6 selector, 107 moving image decoding unit (moving image decoding unit), 108 image signal output terminal, 109 data input control unit, 110 retransmission request determining unit (retransmission request determining unit),
111 retransmission request output terminal, 112 coding type detection unit (coding type detection unit), 113, 202 reference image determination unit (reference image determination unit), 201 coding type input terminal

Claims (7)

[Claims] 1. A moving image communication apparatus having a function of retransmitting when input data has an error, comprising: an encoding type detection unit for detecting an encoding type; and an erroneous reception based on the encoding type information. Reference image determination means for determining whether data is a reference image of correctly received data, and retransmission request determination means for determining whether to request retransmission based on an output of the reference image determination means. A moving image communication device, comprising: 2. The moving image communication apparatus according to claim 1, further comprising: a sequence number storage unit for storing a sequence number; and an error storage unit for storing an error processing result. A moving image communication apparatus, comprising: determining whether data erroneously received is a reference image of data received correctly one time later based on a number and the error processing result. 3. The moving picture communication device according to claim 1, further comprising: a sequence number storage unit configured to store a plurality of sequence numbers; and an error storage unit configured to store a plurality of error processing results. The reference image determining means determines whether or not the erroneously received data is a reference image of the correctly received data before and after based on the plurality of sequence numbers and the plurality of error processing results. Video communication device. 4. The moving image communication device according to claim 1, further comprising: a moving image decoding unit that decodes moving image data, wherein a moving image is decoded after a reference image is determined by the reference image determining unit. A moving image communication device for decoding image data. 5. The coding type detecting means according to claim 1, wherein said coding type detecting means outputs a coding type detected when decoding image data as coding type detection information. The moving image communication device according to any one of the above. 6. The moving picture communication apparatus according to claim 1, further comprising: an ARQ for accurately transferring data on a communication path having an error by detecting an error and retransmitting the data. (Automatic Repeat Reques
t) A moving image communication device comprising control means. 7. The method according to claim 1, wherein the encoding is performed by MPEG (Moving Pictu).
re Expert Group) coding method or H.264. The moving image communication device according to claim 1, wherein the encoding is based on an international standard encoding system such as H.261.