JP3312635B2 - Stored image transmission method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a transmitting device and a receiving device connected to each other via a digital line, the transmitting device comprising: an encoding means for encoding an input audio signal and an input image signal; Communication control means for transmitting encoded data output from the encoding means and transmitting and receiving a control signal, wherein the receiving device comprises: a communication control means for receiving the encoded data and transmitting and receiving a control signal; and And a decoding unit for decoding the stored image.

[0002]

2. Description of the Related Art In order to encode and transmit an image including voice and reproduce the important scene motion and resolution at a high quality on the receiving side, a high-quality code having a high coding speed is required for the image including voice. It is necessary to encode using an encoding device and transmit using a high-speed digital line or micro-line that is faster than the encoding speed, or to use a low-speed digital line that is less than or equal to the encoding speed and take time beforehand. there were.

[0003]

However, if transmission is performed for a long time in advance using a low-speed digital line having a speed lower than the encoding speed, it is necessary to wait until transmission of all scenes is completed. is there.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem and to provide a stored image transmission method and method capable of reproducing important scene motion and resolution with high quality even when transmission is performed using a low-speed digital line. It is to provide a device.

[0005]

Means for Solving the Problems A method of transmitting a stored image of the present invention
The method is to transform the transmitted image signal by motion and / or resolution.
Important scenes and others that you want to reproduce in high quality
And important scenes are moved and / or
Or high coding speed to reproduce the resolution with high quality
And temporarily store it in memory.
Code at a lower coding rate compared to the higher coding rate.
A step of temporarily storing in the memory turned into first before
Only transmit encoded data corresponding to important scenes
Accumulating in a first memory of the receiving device ;
Transmitting the encoded data corresponding to the other scenes,
Storing in a second memory of the receiving device;
The encoded data stored in the memory of the
And store it in the first memory for important scenes
Decoding and outputting the encoded data
I do . The storage image transmission apparatus of the present invention, image transmitting
Reproduce image signals with high quality motion and / or resolution
Important scenes and other scenes,
Critical scenes have higher motion and / or higher resolution at the receiver
Encode at a high encoding speed so that the
Temporarily store in the memory, other scenes with the high sign
Encoding at a lower encoding speed than the
Code that accumulates occasionally and initially corresponds to the important scene
Only the encrypted data, and then
A transmitting apparatus for transmitting those encoding data, first the
Is only the encoded data corresponding to the important scene a transmitting device?
And stores it in the first memory of the own device.
Coded data corresponding to another scene from the transmitting device.
And stores it in a second memory of its own device.
The encoded data stored in is immediately decoded and output.
However, in important scenes, the scenes stored in the first memory are stored.
A receiving device that decodes and outputs encoded data,
The transmitting device and the receiving device are connected via a digital line.
Connected to each other .

[0006]

The transmitting device divides an image to be transmitted into important scenes for which motion and resolution are to be reproduced with high quality and other scenes, and encodes important scenes at a higher coding speed than other scenes. The other scenes are encoded at a lower encoding speed than the important scenes, and the encoded data of the important scenes and the encoded data of the other scenes are multiplexed and transmitted. Is configured to separate the coded data transmitted after being multiplexed into the coded data of the original important scene and the coded data of other scenes.

In the transmitting device, after the images of all the scenes have been encoded as described above, the transmitting device and the receiving device are connected via a digital line, and, for example, the first partial scene of the other scenes is connected. At the same time as transmitting the encoded data, the encoded data of the important scene and the encoded data of the other scenes are multiplexed and transmitted. The receiver first decodes and displays the coded data of the other scenes received first, and then sequentially decodes and displays the coded data of the other scenes received subsequently. On the other hand, encoded data of important scenes is sequentially decoded and displayed when it is time to display important scenes. Therefore,
Even if transmission is performed using a low-speed digital line, all scenes to be transmitted cannot be reproduced with high quality like important scenes, but wait until transmission of all encoded data is completed. This eliminates the need and enables high-quality reproduction of important scene movements and resolutions.

It is also possible to provide an input signal selecting means for selecting whether or not to encode an input image signal.

The encoding means further includes a first transmission encoded data storage means for temporarily accumulating the audio encoded data output of the audio encoding means and outputting the accumulated audio encoded data; A second transmission encoded data accumulating means for temporarily accumulating the first image encoded data output of the image encoding means and outputting the accumulated first image encoded data;
A third transmission encoded data accumulating means for temporarily accumulating the second image encoded data output of the second image encoding means and outputting the accumulated second image encoded data; As encoded data multiplexing means, voice encoded data output of the first transmission encoded data storage means, first image encoded data output of the second transmission encoded data storage means, and third transmission encoded data accumulation It is also possible to provide a configuration including encoded data multiplexing means for multiplexing the second image encoded data output of the means.

[0010] The decoding means further includes: first reception encoded data storage means for temporarily accumulating the audio encoded data output of the encoded data separation means and outputting the accumulated audio encoded data; Second received encoded data storage means for temporarily accumulating the first image encoded data output of the separating means and outputting the accumulated first image encoded data;
A third reception coded data storage means for temporarily storing the second video coded data output of the coded data separation means and outputting the stored second video coded data; Audio decoding means for decoding the audio encoded data output of the first received encoded data storage means as means, first image decoding means, and second image decoding means, respectively.
The first image decoding means for decoding the first image encoded data output of the second reception encoded data storage means and the second image encoded data output of the third reception encoded data accumulation means are A configuration including a second image decoding unit for decoding is also possible.

It is possible to provide a control means for controlling the external input / output device, and a control signal input / output means for the control signal of the external input / output device.

[0012] The first image encoding means may be provided with a second image encoding means.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a stored image transmission apparatus according to one embodiment of the present invention. This storage image transmission device includes a transmission device 100 and a reception device 200, which are connected to each other via a digital line 300.
As the digital line 300, for example, an ISDN line or the like is used.

The transmitting apparatus 100 includes an operation / control section 170 as control means for controlling the entire transmitting apparatus 100, an audio signal input terminal 18 as an audio signal inputting means, and an image signal inputting means as an image signal inputting means. A terminal 11, an A / D converter 118 as an audio signal A / D converter for A / D converting the input audio signal, and an A / D converter as an image signal A / D converter for A / D converting the input image signal D converter 11
0, a switch 130 as input signal selection means for selecting whether to input the signal A / D converted by the A / D converter 110 to the encoder 125, and an A / D converter 118
An encoder 128 as an audio encoding unit for encoding the / D-converted audio signal, and a first image encoding unit for encoding the image signal A / D-converted by the A / D converter 110. An encoder 120; an encoder 125 as second image encoding means for encoding an image signal selected by the switch 130 as input signal selection means; and an encoder 1
Memory 148 as first transmission encoded data storage means for temporarily accumulating the audio encoded data output of No. 28 and outputting the accumulated audio encoded data;
And a memory 140 as a second transmission encoded data storage unit for temporarily storing the encoded image data output of the second and outputting the accumulated first encoded image data.
Memory 145 as third transmission encoded data storage means for temporarily accumulating the image encoded data output of No. 3 and outputting the accumulated second image encoded data, and memories 148 and 14
A signal multiplexing unit 135 as coded data multiplexing means for multiplexing and transmitting the coded data outputs of 0 and 145;
A network control unit 160 is provided as communication control means for transmitting encoded data and transmitting and receiving control signals to and from the receiving device 200 via the digital line 300. Encoder 120,
The 125 and the switch 130 constitute the encoder unit 180.

The receiving apparatus 200 includes an operation / control section 270 as control means for controlling the entire receiving apparatus 200, and a communication control for receiving encoded data and transmitting / receiving control signals with the transmitting apparatus 100 via the digital line 300. A network control unit 260 as means, a signal separating unit 235 as encoded data separating means for separating received encoded data into audio encoded data, first image encoded data, and second image encoded data; And a memory 2 serving as first reception encoded data storage means for temporarily accumulating the audio encoded data output of the signal separation unit 235 and outputting the accumulated audio encoded data.
48, a memory 240 as second reception encoded data storage means for temporarily accumulating the first image encoded data output of the signal separation unit 235 and outputting the accumulated first image encoded data, The memory 245 as a third reception encoded data storage unit for temporarily accumulating the second encoded image data output of the signal separation unit 235 and outputting the accumulated second encoded image data, and the memory 248. A decoder 228 as an audio decoding means for decoding the stored encoded audio data output, and a first image decoding means for decoding the first encoded image data output stored in the memory 240. A decoder 220; a decoder 225 as second image decoding means for decoding the second encoded image data output stored in the memory 245; and the decoder 220 and the decoder 2
A switch 230 as image decoding output multiplexing means for multiplexing the image decoding data output decoded in 25;
A D / A converter 218 as an audio signal D / A converter for D / A converting the decoded audio data, and a D / A converter 218 as an image signal D / A converter for D / A converting the decoded image data.
An A converter 210, an audio signal output terminal 28 as an audio signal output unit, and an image signal output terminal 21 as an image signal output unit are provided. The decoders 220 and 225 and the switch 230 constitute a decoder unit 280.

The memories 148, 140, 145, 248,
240, 245 can use DRAM, magnetic disk device or other digital memory.

A feature of the transmitting apparatus 100 according to the present embodiment is that an audio signal is encoded by one encoder 128 and the memory 1 as a first encoded transmission data storage means.
The image signal is stored in two encoders 1
20 and 125. That is, an image signal to be transmitted is divided into important scenes whose motion and resolution are desired to be reproduced with high quality and other scenes other than the important scenes. , And temporarily stores a second encoded image data output by the encoder 125 as the second image encoding means for encoding at a higher encoding speed than the encoding speed of the image encoding means. The second encoded image data is stored in a memory 145 serving as third encoded encoded data storage means for outputting encoded second image encoded data. Other scenes are compared with the encoding speed of the second image encoded means. Encoder as first image encoding means for encoding at a low encoding speed
And temporarily stores the first encoded image data output and outputs the accumulated first encoded image data.
The first transmission coded data storage means stores the voice coded data output from the memory 148 as the first transmission coded data storage means and the memory 140 as the second transmission coded data storage means. And a signal multiplexing unit 135 as coded data multiplexing means for multiplexing the first image coded data output of the memory 145 and the second image coded data output of the memory 145 as third transmission coded data storage means. Have prepared.

The feature of the receiving apparatus 200 in this embodiment is that the received coded data multiplexed and transmitted from the transmitting apparatus 100 is converted into audio coded data, first image coded data, and second image coded data. A signal separating unit 235 serving as coded data separating means for separating data into data; and a memory 2 serving as first received coded data storage means for storing voice coded data coded by the coder 128 of the transmitting apparatus 100.
48, a decoder 228 serving as an audio decoding means for decoding the audio encoded data output accumulated and accumulated. The image encoded data encoded by the encoder 120 of the transmitting apparatus 100 is decoded. In this configuration, the first image encoded data output stored and stored in the memory 240 as the second received encoded data storage means is decoded by the decoder 220 as the first image decoding means. The image data encoded by the encoder 125 of the transmitting apparatus 100 is stored in the memory 24 as a third reception encoded data storage unit.
5 is decoded by a decoder 225 as a second image decoding means for decoding the second encoded image data output accumulated in the decoder 5, and a decoder as a first image decoding means. A switch 230 as image decoding output multiplexing means for multiplexing and outputting the first image decoded data output of 220 and the second image decoded data output of the decoder 225 as second image decoding means That you have.

In this embodiment, the network controllers 160 and 26
0 not only transmits and receives coded data, but also performs call connection of the digital line 300, transmission device 100 and reception device 20.
Transmission control of a control signal between 0 is also performed. The operation / control units 170 and 270 control the entire apparatus based on human operations and the received control signals 150 and 250, and transmit the control signals 150 and 250 to the other party.

2, 3, 4 and 5 are explanatory diagrams of the present embodiment. FIG. 2 shows the resolution of a thinned frame of a moving image frame, such as a videophone, in which the encoding speed is low. 3 and 4 show examples of a form of transmission of encoded data, and FIG. 5 shows an example of a state in which the movement of an important scene can be faithfully reproduced. Also,
2, 3, 4, and 5, F indicates a frame of a moving image, S indicates another scene, M indicates an important scene, and the numbers in the figures indicate frame numbers.

Hereinafter, the operation of the present apparatus will be described with reference to FIGS.
This will be described with reference to FIGS.

First, an audio signal input from an external input device 400 such as a video tape recorder or a laser video disk player is A / D-converted by an A / D converter 118, encoded by an audio signal encoder 128, and encoded. The data is stored in the memory 148. The A / D converter 110 converts the image signal input simultaneously with the audio signal from the external input device 400 into an A / D signal.
The image data is converted and encoded by the encoder 120 as first image encoding means, and the encoded data is stored in the memory 140. In an important scene in the input image, the switch 130 as the input signal selecting means is closed, and the encoder 125 as the second image encoding means operates to store the encoded data in the memory 145.
To accumulate. Encoder 12 as first image encoding means
At 0, other scenes are encoded at a lower encoding speed than the encoder 125. Therefore, the decoded image is, for example, a frame-forward image as shown in FIG. On the other hand, for an image of an important scene, the switch 130 is closed, and the encoder 125 encodes other scenes by the encoder 125 so that the motion and resolution can be reproduced with high quality on the receiving side.
Performs high quality coding at a higher coding speed than that of. After the encoding of the images of all the scenes is completed, the image encoded data and the audio encoded data of each scene are multiplexed by the signal multiplexing unit 135 as encoded data multiplexing means.

Next, the transmitting device 100 or the receiving device 20
0, a call connection is made, the transmitting apparatus 100 and the receiving apparatus 200 are connected via the digital line 300, and a data link for transmitting encoded data by exchanging control signals between the network control units 160 and 260 is established. Let it be established.
When the data link is established, the transmission of the encoded data starts via the signal multiplexing unit 135 of the transmitting device 100 and the signal separating unit 235 of the receiving device 200, and the encoded data is encoded by the encoder 128 by the signal separating unit 235. The encoded audio data is decoded by the decoder 228, the first encoded image data encoded by the encoder 120 is encoded by the decoder 220, and encoded by the encoder 125. The memory for storing the second encoded image data is selected according to each received encoded data so as to be decoded by the decoder 225.

As a method of transmitting encoded data, for example, as shown in FIG. 3, first, only encoded data corresponding to an important scene M in an image signal is transmitted, and
0 is stored in the memory 245. Next, the other scene S
Is transmitted and stored in the memory 240 of the receiving device 200. At this time, the switch 230 of the receiving device 200 is connected to the a side, and the encoded data stored in the memory 240 is immediately decoded by the decoder 220, and D / A converted by the D / A converter 210. Output. Here, in an important scene, the switch 230
Is connected to the b side, and the data decoded by the decoder 225 is
The signal is input to the / A converter 210, D / A converted, and output.
Therefore, the image shown in FIG. 5 is reproduced in the receiving device 200, and an important scene and other scenes can be reproduced continuously. Also, the audio encoded data is
It is sent at the same time as the encoded image data, and output in synchronization with the image signal.

In this embodiment, it has been described that whether or not encoding is performed by the encoder 125 is selected by the switch 130 as input signal selecting means. However, all input signals except for the switch 130 are encoded. It is apparent that the stored image transmission apparatus of the present invention can be realized even when unnecessary encoded data is not multiplexed in the signal multiplexing unit 135. In this embodiment, as means for storing encoded data, memories 148, 140 and 145 are used.
However, it is apparent that the stored image transmission apparatus of the present invention can be realized even if the signal multiplexing unit 135 directly multiplexes the data without the storage means.

In the present embodiment, the mode in which the encoded data of the important scene is transmitted first, and then the other scenes are transmitted has been described. However, as shown in FIG. It is also possible to transmit the image first, decode it on the receiving side and start displaying it, then transmit the encoded data of the important scene, and continue decoding and displaying the other scenes It is clear.

Further, after the transmitting apparatus 100 completes the encoding of the images of all the scenes, for example, the encoded data of the first partial scene of the other scenes is transmitted, and at the same time, the encoded data of the important scene and the encoded data of the other scenes are transmitted. The encoded data of the scene is multiplexed and transmitted. In the receiving device 200,
First, the coded data of the other scenes received first is temporarily stored in the memory, decoded and displayed, and the coded data of the other scenes subsequently received are also temporarily stored in the memory and sequentially decoded and displayed. On the other hand, the encoded data of important scenes are sequentially stored in the memory, and when the time to display the important scenes is reached, the encoded data stored in the memory is sequentially decoded and displayed, so that the movement of the important scenes is performed. It is clear that it is possible to reproduce high quality and resolution.

The receiving device 200 has a memory 24
8, 240, and 245, and can reproduce the received image and audio signals as many times as necessary.
Furthermore, fast-forwarding can be performed by reproducing only the portion S in FIG. It is apparent that the stored image transmission apparatus of the present invention can be realized even in a configuration without the memories 248, 240 and 245.

The transmitting device 100 operates and controls the function of controlling the external input device 400 such as a video tape recorder, a laser video disk player, and a recorder.
It is apparent that the external input device 400 can also be controlled if the external input device 400 is provided with the external input device control signal input / output terminal 12 as an input / output unit for the control signal 150.

The receiving apparatus 200 has a function of controlling an external output device such as a video tape recorder or a laser video disk recorder in the operation / control section 270, and receives an external output device control signal input / output as a control signal input / output means. Obviously, if the output terminal 22 is provided, the external output device can be controlled.

FIGS. 6 and 7 respectively show the encoder 120 of FIG.
And 125, and a detailed configuration example of the decoders 220 and 225.

The encoders 120 and 125 include a subtractor 300 as subtraction means for obtaining an inter-frame prediction error between the current frame and the predicted frame, a converter 305 as a conversion means for encoding the inter-frame prediction error, A variable length encoder 310 as a variable length encoder for quantizing the obtained result and performing variable length encoding, and an inverse variable length encoder as an inverse variable length encoder for restoring the conversion result from the variable length code 315, an inverse transformer 320 as an inverse transform unit for obtaining an original inter-frame prediction error, and an adder 325 as an addition unit for restoring the current frame by adding the inter-frame prediction error and the previous Fourierm. A frame memory 330 as delay means for delaying the current frame.

The decoders 220 and 225 are composed of an inverse variable length encoder 330 as an inverse variable length encoder for restoring the conversion result from the variable length code, and an inverse variable encoder as an inverse transformer for obtaining the original inter-frame prediction error. A converter 335, an adder 340 as addition means for adding the inter-frame prediction error to the previous frame to restore the current frame, and a frame memory 345 as delay means for delaying the restored current frame
Is provided.

Hereinafter, the encoder 120 (125) and the decoder 2
20 (225) will be described.

First, the encoder 120 (125) will be described. A subtractor 300 subtracts an inter-frame prediction value from a signal of the current frame that has been A / D converted by the A / D converter 110 to obtain an inter-frame prediction error. After performing the transform, the variable length encoder 310 performs quantization and variable length coding on the DCT transform result, and outputs the obtained variable length encoded data to the memory 140 or 145. Also, the inverse variable length encoder 315 performs inverse variable length encoding on the variable length coded data, and the inverse transformer 320 performs inverse transform to obtain the original inter-frame prediction error. Next, the current frame is restored by adding the calculated inter-frame prediction error and the previous frame by the adder 325. The restored current frame is stored in the frame memory 3
The data is accumulated in the data 30 and delayed and used as a predicted value of the next frame. As a method of converting the inter-frame prediction error in the converter 305, Hadamard transform or the like can be used in addition to DCT transform.

In the decoder 220 (225), the memory 24
The coded data of 0 or 245 is input, the input coded data is subjected to inverse variable length encoding by the inverse variable length encoder 330, and the inverse DCT transform is performed by the inverse transformer 335 to obtain the original inter-frame prediction error. Next, the calculated inter-frame prediction error and the previous frame are added by the adder 340 to restore the current frame and output it to the D / A converter 210. The restored current frame is accumulated in the frame memory 345, delayed, and used as a predicted value of the next frame. The converter 3
As a method of converting the inter-frame prediction error in 05,
DCT, Hadamard transform, etc. can be used.

FIGS. 8 and 9 show other embodiments of the stored image transmission apparatus according to the present invention, respectively, and show detailed configuration examples of the encoders 120 and 125 and the decoders 220 and 225 of FIG.
In this embodiment, parts other than the encoder unit 180 and the decoder unit 280 in FIG. 1 are exactly the same as those in FIG.

The encoder 120 (125) includes a subtractor 400 as subtraction means for obtaining an inter-frame prediction error between the current frame and the predicted frame, a converter 405 as a conversion means for encoding the inter-frame prediction error, and A variable length encoder 410 as variable length encoding means for quantizing the result of the conversion and performing variable length encoding, and a switch as variable length encoded data output destination selecting means for selecting an output destination of the variable length encoded data. 415, an inverse variable length encoder 420 as an inverse variable length encoding unit for restoring a conversion result from the variable length encoded data, and an inverse transformation as an inverse transformation unit for obtaining an original inter-frame prediction error 425, an adder 430 as an adding means for adding the inter-frame prediction error to the previous frame and restoring the current frame, and delaying the restored current frame. Frame memory 44 as extending means
0 and 445, a switch 435 as a frame memory selecting means for selecting the frame memory 440 or 445 for storing the restored current frame, and a switch 450 as a frame memory output selecting means for selecting the output of the frame memory 440 or 445. Is provided.

The decoder 220 (225)
455 as an input selecting means for selecting an input from the first and second 245, and an inverse variable length encoder 4 as an inverse variable length encoding means for restoring the DCT transform result from the variable length code
60, an inverse transformer 465 as an inverse transform unit for obtaining the original inter-frame prediction error, an adder 475 as an addition unit for adding the inter-frame prediction error to the previous frame and restoring the current frame, and Frame memories 480 and 485 as delay means for storing and delaying the current frame, and a frame memory 480 or 485 for storing
Switch 4 as frame memory selection means for selecting
75 and a switch 4 as a frame memory output selecting means for selecting an output of the frame memory 480 or 485.
90.

Hereinafter, the encoder 120 (125) and the decoder 2
The operation of 20 (225) will be described with respect to the important scene and other scene encoding methods.

First, an important scene encoding method will be described.

First, the switches 415, 435, 450 of the encoder 120 (125) and the decoder 220 (225)
455, 490 and 475 are all connected to the b side. A / D
The interframe prediction value stored in the frame memory 445 is subtracted by the subtractor 400 from the signal of the current frame A / D converted by the converter 110 to obtain an interframe prediction error, and the converter 405 converts the interframe prediction error into an interframe prediction error. On the other hand, for example, DCT transformation is performed, and the variable length encoder 410 performs quantization and variable length encoding on the DCT transformation result, and outputs the obtained variable length encoded data to the memory 145. Also, the inverse variable length encoder 420 performs inverse variable length encoding on the variable length encoded data, and the inverse transformer 425 inversely transforms the data to obtain the original inter-frame prediction error. Next, the current frame is restored by adding the calculated inter-frame prediction error and the previous frame by the adder 430, and the restored current frame is stored in the frame memory 445. Next, the current frame stored in the frame memory 445 is used as a predicted value of the next frame.

In the decoder 220 (225), the input coded data in the memory 245 is subjected to inverse variable length encoding by the inverse variable length encoder 460, and further subjected to inverse DCT transform by the inverse transformer 465 to perform the original inter-frame prediction. Find the error. Next, the addition of the inter-frame prediction error and the previous frame stored in the frame memory 485 is performed by the adder 470, and the current frame is restored and output to the D / A converter 210. The restored current frame is stored in the frame memory 485. Next, the current frame stored in the frame memory 485 is used as a predicted value of the next frame.

Next, another method of encoding a scene will be described.

First, the switches 415, 435, 450 of the encoder 120 (125) and the decoder 220 (225)
455, 490 and 475 are all connected to the a side. A / D
The interframe prediction value accumulated in the frame memory 440 is subtracted by the subtractor 400 from the signal of the current frame A / D converted by the converter 110 to obtain an interframe prediction error, and the converter 405 converts the interframe prediction error into an interframe prediction error. On the other hand, for example, DCT transformation is performed, quantization and variable length encoding are performed on the DCT transformation result by the variable length encoder 410, and the obtained variable length encoded data is output to the memory 140. Also, the inverse variable length encoder 420 performs inverse variable length encoding on the variable length encoded data, and the inverse transformer 425 inversely transforms the data to obtain the original inter-frame prediction error. Next, the current frame is restored by adding the obtained inter-frame prediction error and the previous frame by the adder 430, and the restored current frame is accumulated in the frame memory 440. Next, the current frame stored in the frame memory 440 is used as a predicted value of the next frame.

In the decoder 220 (225), the input coded data in the memory 240 is subjected to inverse variable length encoding by the inverse variable length encoder 460, and further subjected to inverse DCT transform by the inverse transformer 465 to perform the original inter-frame prediction. Find the error. Next, the addition of the inter-frame prediction error and the previous frame stored in the frame memory 480 is performed by the adder 470, and the current frame is restored and output to the D / A converter 210. Also, the restored current frame is stored in the frame memory 480. Next, the current frame stored in the frame memory 480 is used as a predicted value of the next frame. It is clear that various encoding parameters of the encoder 220 (225) may be changed between encoding an important scene and encoding other scenes.

Therefore, by employing the above-described encoding method, encoding and decoding of important scenes and other scenes can be realized by the same encoder and decoder.

As a method of converting the inter-frame prediction error in the converter 405 and the inverse converters 425 and 465, Hadamard transform or the like can be used in addition to DCT.

[0050]

As described above, according to the present invention, an image to be transmitted is divided into important scenes and other scenes, and important scenes are higher than other scenes in order to reproduce motion and resolution with high quality. After encoding at the encoding speed, encoding other scenes at a lower encoding speed than the important scene, and encoding the images of all the scenes, for example, encoding the first partial scene of the other scenes Coded data of important scenes and coded data of other scenes are multiplexed and transmitted at the same time as the coded data of the important scenes. It is separated from the encoded data of the scene, the encoded data of the other scenes received first is decoded and displayed, and the encoded data of the other scenes received continuously is decoded sequentially. On the other hand, coded data of important scenes are sequentially stored in a memory, and when important scenes have to be displayed, they are sequentially decoded and displayed, so that they can be transmitted using a low-speed digital line. Even if it does, all scenes to be transmitted cannot be reproduced with high quality like important scenes, but there is no need to wait until transmission of all encoded data is completed, And resolution can be reproduced with high quality.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a stored image transmission device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a mode in which a coding speed is low and frames of a moving image are transmitted at a reduced resolution of a thinned frame.

FIG. 3 is a diagram illustrating an example of a transmission form of encoded data.

FIG. 4 is a diagram illustrating an example of a transmission form of encoded data.

FIG. 5 is a diagram showing a state in which the movement of an important scene is faithfully reproduced.

FIG. 6 is a block diagram illustrating a configuration example of encoders 120 and 125 in FIG.

FIG. 7 is a block diagram illustrating a configuration example of decoders 220 and 225 in FIG.

FIG. 8 is a block diagram showing another configuration example of the encoders 120 and 125 in FIG.

9 is a block diagram illustrating another configuration example of the decoders 220 and 225 in FIG.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 Transmitting device 200 Receiving device 300 Digital line 400 External input device 170, 270 Operation / control unit 118 Audio signal A / D converter 110 Image signal A / D converter 130 Switch 128 Encoder 120 Encoder 125 Encoder 148 Memory 140 Memory 145 Memory 135 Signal multiplexing unit 160, 260 Network control unit 235 Signal separation unit 248 Memory 240 Memory 245 Memory 228 Decoder 220 Decoder 225 Decoder 230 Switch 218 Audio signal D / A converter 210 Image signal D / A converter 150, 250 Control signal 11 Image signal input terminal 18 Audio signal input terminal 21 Image signal output terminal 28 Audio signal output terminal 12 External input device control signal input / output terminal 22 External output device control signal input / output terminal F Frame of moving image S Other of M M Important scene 300, 400 Subtractor 305, 405 Transformer 310, 410 Variable length encoder 315, 330, 420, 460 Inverse variable length encoder 320, 335, 425, 465 Inverse transformer 325, 340 , 430, 470 Adders 330, 345, 440, 445, 480, 485
Frame memory 415, 435, 450, 455, 475, 490
switch

Continuation of the front page (56) References JP-A-2-254887 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N ^7/ 24-7/68 H04N ^7/ 16-7 / 173 H04N 5/91-5/956

Claims (2)

(57) [Claims] An image signal to be transmitted is moved and / or moved.
Are important scenes for which you want to reproduce the resolution with high quality and others
Other scenes, important scenes move on the receiving side
And / or high enough to reproduce the resolution in high quality
Encode at the encoding speed, temporarily store in memory,
Other scenes have a lower coding rate compared to the higher coding rate.
And temporarily storing the data in a memory, and first, only the encoded data corresponding to the important scene is stored.
Transmitting and storing in a first memory of the receiving device
If, then, the coded data corresponding to the other scene Den
Transmitting and storing the encoded data in the second memory of the receiving device;
The important scene is stored in the first memory
To decode and output the encoded data stored in
Stored image transmission method having a loop. 2. The method according to claim 1, further comprising the steps of :
Are important scenes for which you want to reproduce the resolution with high quality and others
Other scenes, important scenes move on the receiving side
And / or high enough to reproduce the resolution in high quality
Encode at the encoding speed, temporarily store in memory,
Other scenes have a lower coding rate compared to the higher coding rate.
And temporarily store it in memory.
Only the encoded data corresponding to the required scene is transmitted, and then
Transmit encoded data corresponding to the other scene
First, only the encoded data corresponding to the important scene is transmitted to the transmitting device.
Received from the transmitting device and stored in the first memory of the own device
Then, the encoded data corresponding to the other scene is
Received from the transmitting device and stored in its own second memory
The encoded data stored in the second memory is immediately
And outputs the decoded data. In an important scene, the first
Receiving and decoding encoded data stored in memory
Communication device, wherein the transmission device and the reception device are connected via a digital line.
Stored image transmission devices connected to each other.