JP3128393B2 - Compressed video playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressed moving picture reproducing apparatus for decoding and reproducing compressed and coded moving picture data, and more particularly to a compressed moving picture reproducing apparatus capable of performing reverse reproduction. .

[0002]

2. Description of the Related Art In recent years, with the development of digital signal processing, LSI technology, and image coding technology, a technology for compressing a huge amount of moving image data has become familiar, and has begun to be applied to videophones and videoconferencing systems. I have. CD,
With the spread of storage media such as DAT, demands for services using media storing moving images are increasing.
Under such a background, ISO-IEC / JTC1 / S
C2 / WG11 / MPEG (Moving Picture Expert Gro
Up), the standardization of a moving picture coding method for storage media is being promoted.

[0003] The current moving image compression coding system is roughly divided into two processes, one of which is a certain frame (1).
Screen) is regarded as a still image, and intra-frame compression (MPEG method) that compresses independently of other frames. The other uses the similarity of the image to close a frame close to the intra-frame compressed frame. This is inter-frame compression represented by a small amount of information.

The basic principle of the above-mentioned MPEG system is to perform motion-compensated inter-frame prediction, perform DCT (discrete cosine transform) on the prediction error, quantize the result, and sequentially perform variable-length coding from low-frequency components. Motion-compensated inter-frame prediction coding does not simply encode the difference between frames,
This is to perform predictive coding with motion compensation from nearby frames. Further, in the MPEG system, in addition to the forward prediction which predicts from the past frame in the inter-frame prediction, the backward prediction which predicts from the future frame and the average value prediction of both of them are adopted, and the best prediction among the three is adopted. Is selected to improve the inter-frame prediction efficiency.

Next, the operation of decoding and reproducing moving image data encoded and recorded according to the compression encoding method of the conventional compressed moving image reproducing apparatus will be described with reference to the drawings.

FIG. 5 is a block diagram of a conventional compressed moving picture reproducing apparatus.

In FIG. 5, reference numeral 1 denotes a recording medium on which compression-encoded video data is recorded; 2, a variable-length decoder for variable-length decoding of the compressed video data; and 3, a variable-length decoder. An inverse quantizer 4 for inversely quantizing the obtained data is an inverse DCT operation unit for performing an inverse DCT on the inversely quantized data. Reference numeral 5 denotes a frame memory B for storing already decoded past frame data required for forward inter-frame prediction, and reference numeral 6 denotes a frame memory A for storing future frame data required for backward inter-frame prediction. . 7
Is a motion-compensated forward predicted value calculator that calculates a forward predicted value in consideration of motion compensation with reference to the frame memory B5, and 8 is a backward predicted value in consideration of motion compensation with reference to the frame memory A6. , A motion-compensated bidirectional predicted value calculator 9 that calculates a bidirectional predicted value in consideration of motion compensation by referring to both the frame memory B5 and the frame memory A6.
Is a switch for selecting a predictor for calculating a predicted value according to the type of inter-frame prediction when the frame to be decoded is decoded. Numeral 11 denotes the difference data of the image inversely DCTed by the inverse DCT calculator 4 and the prediction values calculated by the motion compensation forward prediction value calculator 7, the motion compensation backward prediction value calculator 8, and the motion compensation bidirectional prediction value calculator 9. An adder 13 for adding, a display 13 for controlling and displaying the decoded image data, and 12 an inverse DCT calculator depending on whether the frame to be decoded is compressed within a frame or between frames. 4 to the display 13 via the adder 11 or directly to the display 13
This is a switch for selecting whether to send to the display unit 13.

[0008] The operation of the conventional compressed moving picture reproducing apparatus thus configured will be described.

First, when the image data sent from the recording medium 1 is data compressed in a frame, the compressed data is variable in the order of a variable length decoder 2, an inverse quantizer 3, and an inverse DCT operator 4. Long decoding, inverse quantization and inverse DCT are performed,
The decoded image data is sent to the display 13 and stored in the frame memory A6 via the path 14. The image data stored in the frame memory A6 is used when the image data compressed in the frame or the image data compressed in the forward frame is transmitted from the recording medium 1.
It is moved to the frame memory B5.

Next, if the data transmitted from the recording medium 1 is data predicted in the forward inter-frame, the transmitted data is compression-coded inter-frame difference data, and this data is of variable length. Variable-length decoding, inverse quantization, inverse DCT and decoding are performed in the order of the decoder 2, the inverse quantizer 3, and the inverse DCT operator 4. On the other hand, the prediction value calculated by the motion compensation forward prediction value calculator 7 selected by the switch 10 is added by the adder 11 to the decoded difference data. As a result, the decoded image data is sent to the display unit 13 and stored in the frame memory A6 via the path 14.

When the image data sent from the recording medium 1 is data compressed between backward frames and data compressed between frames in both directions, the image data is transmitted in the same manner as in the case where the data is compressed between forward frames. , The difference data is processed by the variable-length decoder 2, the inverse quantizer 3, and the inverse DCT calculator 4, and the motion-compensated backward predicted value calculator 8 or the motion-compensated bidirectional predicted value calculator 9 selected by the switch 10. Predicted Value and Adder 1
The image data added and decoded at 1 is sent to the display 13. This image data is not sent to the frame memory A6.

In the MPEG system, in consideration of special reproduction such as random access, high-speed reproduction, and reverse-order reproduction, a minimum length of one frame to any length including a frame that is compression-coded by intra-frame compression of at least one frame is considered. A frame unit called GOP (Group Of Picture) constituted by the number of frames is introduced. In this case, as a special reproduction method, for example, edited by Hiroshi Yasuda: “International Standard for Multimedia Coding” (published by Maruzen Co., Ltd.), p.154-155
In the high-speed reproduction described in (1), high-speed reproduction is realized by speeding up the cueing of only the intra-frame compression-coded image in each GOP and decoding and displaying only that image. As the reverse reproduction, a method of performing reverse reproduction by storing decoded image data for a GOP in a specific memory is described.

Next, a method for performing the reverse reproduction will be described with reference to FIG.

FIG. 6 is a block diagram of a configuration in which a conventional compressed moving image reproducing apparatus can perform reverse reproduction.

In FIG. 6, 15 is a recording medium on which compressed moving image data is recorded, 16 is a decoder for decoding the compressed moving image data, and 17 is a display for displaying the decoded moving image data. A frame buffer memory 18 stores decoded image data to be reproduced and displayed at the time of reverse reproduction. Reference numeral 19 denotes a switch for switching between moving image data to be reproduced and displayed during forward reproduction and reverse reproduction, from the decoder 16 or the frame buffer memory 18.

In this operation, first, the compressed moving image data recorded on the recording medium 15 is decoded by the decoder 16 and the decoded moving image data is sent to the display 17 while the frame buffer is Stored in the memory 18. At the time of forward reproduction, the moving image data decoded by the decoder 16 is sent to the display 17 for reproduction and display. At the time of reverse reproduction, the moving image data stored in the frame buffer memory 18 is read in reverse order. The display 17 reproduces the data in reverse order.

[0017]

When the reverse reproduction is performed by the above-described conventional method, the time during which the reverse reproduction can be performed is determined by the size of the frame buffer memory 18. That is, the number of frames of decoded image data that can be stored in the frame buffer memory 18 determines the reverse reproduction time. Therefore,
In order to perform reverse order reproduction for a long time, the frame buffer memory 18 needs to have a large capacity so that a large amount of decoded image data can be stored.

For example, assuming that one pixel is represented by 8 bits in an RGB image of 360 × 240 pixels as a frame format of a color moving image, the image data amount of one frame is about 2 M bits. .
Assuming that one GOP is composed of 15 frames, the frame buffer memory 1 for reverse reproduction is used.
8 requires a memory having a size of about 30 Mbits for image data for one GOP. Furthermore, if long-term reverse reproduction is to be performed, a much larger frame buffer memory is required.

It is therefore an object of the present invention to provide a compressed moving picture reproducing apparatus which enables long-time reverse reproduction even if the capacity of the buffer memory is small.

[0020]

A compressed moving picture reproducing apparatus according to the present invention comprises decoding means for reading out and decoding compressed coded data from a recording medium in which moving picture data is coded and recorded. A compressed memory reproducing apparatus comprising: a frame memory for storing image data necessary for the decoding; and a display unit for displaying the decoded moving image data. A reverse encoding means for performing compression encoding in order to perform a reverse reproduction order; a buffer memory for storing image data compressed and encoded by the reverse encoding means; Input data selecting means for selecting the compression-encoded data in the buffer memory.

[0021]

In the present invention, the moving picture data decoded by the forward reproduction is subjected to compression encoding by the reverse encoding means so as to be in the reverse reproduction order, and the compression encoded data is stored in the buffer memory. When playing back in reverse order,
The compression-encoded moving image data stored in the buffer memory is read in the reverse direction, decoded, and displayed, thereby performing reverse reproduction.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a compressed moving picture reproducing apparatus according to the present invention.

FIG. 1 is an explanatory diagram showing the operation principle of a compressed moving picture reproducing apparatus according to one embodiment of the present invention. It is also a claim correspondence diagram.

In FIG. 1, reference numeral 20 denotes a recording medium on which compressed moving image data is recorded; 21a, a decoding means for decoding the compressed moving image data; and 21b, image data necessary for decoding. A frame memory 22 to be stored; display means 22 for reproducing and displaying the decoded moving picture; 23, a reverse coding means for compressing and decoding the decoded moving picture data in reverse order; and 24, a reverse coding means 23. A buffer memory for storing the encoded data; and 25, an input data selection means for selecting whether to decode the data from the recording medium 20 or to decode the data stored in the buffer memory 24 during reverse reproduction. It is. The image data decoded by the decoding means 21a is
2 and is sent to the reverse encoding means 23 to be compression-encoded in the reverse order and stored in the buffer memory 24. At the time of reverse reproduction, the encoded data stored in the buffer memory 24 is sent to the decoding means 21a by the input data selection means 25, and after being decoded, sent to the display means 22 for reproduction and display. .

In other words, the configuration of the present embodiment is different from the conventional compressed moving picture reproducing apparatus described above in that the reverse encoding means 23 for compressing and decoding the decoded image data again, and the reverse encoding means 23 And a buffer memory 24 for storing data encoded by the reverse encoding means 23. In order for the moving picture data decoded by the forward reproduction to be set in the order of the reverse reproduction by the reverse encoding means 23. The compression-encoding is performed, and the compression-encoded data is stored in the buffer memory 24. In the case of the reverse reproduction, the compression-encoded moving image data stored in the buffer memory 24 is read in the reverse direction. Then, by decoding and displaying the decoded data, reverse reproduction is performed.

FIG. 2 is a block diagram showing a specific configuration of the compressed moving picture reproducing apparatus according to one embodiment of the present invention.

Reference numeral 20 denotes a recording medium on which the compression-encoded data is recorded; 27, a variable-length decoder for performing variable-length decoding on the compressed-encoding data; and 28, an inverse quantization unit for performing inverse quantization on the variable-length-decoded data. A quantizer 29, an inverse DCT calculator for performing an inverse DCT operation on the inversely quantized data, a motion compensation forward predictor calculator 31 for calculating a forward inter-frame predicted value in consideration of motion compensation, and a motion compensator 32, A motion-compensated backward predictor calculator 33 for calculating a backward inter-frame predicted value taking into account compensation; a motion-compensated bidirectional predictor calculator 33 for calculating a bidirectional inter-frame predicted value taking into account motion compensation;
A frame memory A 34 stores frame data required for the motion compensation backward prediction value calculator 32 to calculate the prediction value, and a frame memory A 35 required for the motion compensation forward prediction value calculator 31 to calculate the prediction value. Frame memories B and 36 for storing frame data are switches for switching between three types of inter-frame prediction value calculators depending on the type of inter-frame prediction of a moving image to be decoded, and 37 is subjected to inverse DCT by an inverse DCT calculator 29. Decoded difference data and motion compensation forward prediction value calculator 31, motion compensation backward prediction value calculator 3
2. An adder for adding the predicted value calculated by the inter-frame predicted value calculator of the motion compensated bidirectional predicted value calculator 33.

Reference numeral 39 denotes a DCT operation unit for performing a DCT operation on moving picture data decoded at the time of forward reproduction,
Numeral 40 denotes a quantizer for quantizing DCT-calculated data, numeral 41 denotes a variable-length encoder for performing variable-length encoding on the quantized data, and numeral 42 denotes a forward direction in consideration of motion compensation. A motion-compensated forward predictor for calculating an inter-frame predicted value, 43 is a motion-compensated backward predictor for calculating a backward predicted value in consideration of motion compensation, and 44 is a motion for calculating a bidirectional predicted value in consideration of motion compensation. A compensation bidirectional predictor 45, a switch for switching between three types of predictors: a motion-compensated forward predictor 42, a motion-compensated backward predictor 43, and a motion-compensated bidirectional predictor 44, depending on the type of inter-frame prediction of a moving image to be encoded; Reference numeral 46 denotes a frame calculated from the motion picture data to be encoded by the motion compensation forward predictor 42, the motion compensation backward predictor 43, and the motion compensation bidirectional predictor 44. A subtractor for subtracting the predicted value; 24, a buffer memory for storing data to be variable-length encoded by the variable-length encoder 41; 48, a buffer memory for storing image data to be decoded from the recording medium 20 or the buffer memory 24; A switch 49 for switching is a display for reproducing and displaying the decoded moving image.

The variable length decoder 27 shown in FIG.
Inverse quantizer 28, inverse DCT calculator 29, motion compensation forward prediction value calculator 31, motion compensation backward prediction value calculator 32, motion compensation bidirectional prediction value calculator 33, adder 37
Constitutes the decoding means 21a shown in FIG. Similarly, the DCT calculator 39, the quantizer 40, the variable length encoder 41, the motion compensation forward predictor 42, the motion compensation backward predictor 43, the motion compensation bidirectional predictor 44, and the display 49
This constitutes the reverse encoding unit 23 shown in FIG. And
The frame memory A34 and the frame memory B35 constitute the frame memory 21b shown in FIG.

Next, the overall operation of the compressed moving picture reproducing apparatus of this embodiment will be described.

First, when the data sent from the recording medium 20 is compressed data in a frame, the data is subjected to variable length decoding by a variable length decoder 27, an inverse quantizer 28, and an inverse DCT operation unit 29, respectively. , Inverse quantization, inverse DCT
The calculated and decoded image data is sent to the display 49 and passes through the path 30 to the frame memory A34.
Is stored. Next, the decoded image data stored in the frame memory A34 is transmitted from the storage medium 26 as intra-frame compressed image data or forward inter-frame compressed image data.
Moved to 35.

On the other hand, the decoded image data for one frame is first sent to a subtractor 46 through a path 50 in order to perform encoding. The DCT operation, quantization, and variable length encoding are performed on the quantizer 40 and the variable length encoder 41, respectively, and the compression encoded data is stored in the buffer memory 24.

If the data transmitted from the recording medium 20 is data predicted in the forward inter-frame, the transmitted differential data is transmitted to the variable length decoder 2 in the same manner as described above.
7. The decoding process is performed by the inverse quantizer 28 and the inverse DCT calculator 29, respectively, and the predicted value calculated by the motion compensation forward predicted value calculator 31 is added by the adder 37.
The image data thus decoded is sent to the display 49 and stored in the frame memory 34 via the path 30. Further, the decoded image data is transferred to the path 50
To the subtractor 46 and the motion compensated forward predictor 4
The predicted value predicted by 2 is subtracted in the subtractor 46. The difference data between frames obtained by the subtraction is D
The DCT, quantization, and variable-length coding are performed by the CT calculator 39, the quantizer 40, and the variable-length encoder 41, and compression coding is performed. Then, the encoded difference data is stored in the buffer memory 24.

If the data sent from the recording medium 20 is backward inter-frame prediction or bidirectional inter-frame prediction data, the variable-length decoding is performed in the same manner as the decoding of the forward inter-frame prediction data. Chemistry 2
7. Decoding processing is performed by the inverse quantizer 28 and the inverse DCT calculator 29, and the prediction value calculated by the motion compensation backward prediction value calculator 32 and the motion compensation bidirectional prediction value calculator 33 is added by the adder 37. You. The resulting decoded image data is sent to the display 49 and also to the subtractor 46 via the path 50, where the decoded image data between the backward frames predicted by the motion compensated backward predictor 43 and the motion compensated bidirectional predictor 44, respectively. The prediction value and the bidirectional inter-frame prediction value are reduced to obtain inter-frame difference data.
The difference data is obtained by a DCT calculator 39, a quantizer 40,
After being subjected to DCT operation, quantization, variable length encoding and compression encoding by the variable length encoder 41, the buffer memory 2
4

At the time of the reverse reproduction, the data to be decoded is switched from the recording medium 20 to the buffer memory 24 by the switch 48, and the compressed and coded data stored in the buffer memory 24 is read in the reverse order. 27, an inverse quantizer 28, and an inverse DCT operator 29 to perform variable length decoding, inverse quantization, and inverse DCT, respectively. Next, if the compressed coded data is not compressed in the frame in the reverse coding path, the inverse DCT calculator 29 performs the inverse DCT operation.
The calculated data is sent to the display 49 and is reproduced and displayed.

If the data is compressed between frames,
The data subjected to the inverse DCT operation by the inverse DCT operation unit 29 is subjected to the motion compensation forward prediction value calculation unit 3 depending on whether the inter-frame compression is forward, backward, or in both directions.
1. The predicted value calculated by any one of the motion-compensated backward predicted value calculator 32 and the motion-compensated bidirectional predicted value calculator 33 is added to the adder 37, and the decoded image data obtained by the addition is added. The data is sent to the display 49 and is reproduced and displayed.

Next, the procedure for processing image data in this embodiment will be described.

FIG. 3 is an explanatory view of a data processing procedure of the compressed moving picture reproducing apparatus according to one embodiment of the present invention, and FIG. 4 is an explanatory view of a data processing procedure of reverse reproducing of the compressed moving picture reproducing apparatus.

In FIG. 3, I indicates image data compressed in a frame, P indicates image data compressed by forward inter-frame prediction, B indicates image data compressed by bi-directional prediction, and numerals are displayed. The order is shown. The frame memory A34 and the frame memory B35 are each divided into three memory portions, that is, a memory a62, a memory b63, and a memory c64, and each store the decoded image data. It is assumed that decoding of each piece of compressed image data requires a time corresponding to one frame display period.

The data on the recording medium 20 is recorded in an arrangement as shown in FIG.

First, the intra-frame compressed image data I0 on the recording medium 20 is subjected to variable length decoding, inverse quantization, inverse D
After performing the CT operation, the data is decoded and stored in the frame memory a during one frame display period. Next, the image data P3 compressed by the forward inter-frame prediction on the recording medium 20 that arrives is decoded and stored in the frame memory b. Further, the image data B1 compressed by the bidirectional prediction on the recording medium 20 arriving next is decoded and stored in the frame memory c, and the image of the image data I0 compressed in the frame is displayed. Store in buffer memory.

Similarly, the image data B2 compressed in the subsequent bidirectional prediction on the recording medium 20 is decoded and stored in the frame memory c, the image data B1 is displayed, and the image data B1 is compressed by the forward interframe prediction in the frame memory b. The image data B3 is subjected to data compression by motion compensated bidirectional prediction with reference to the obtained image data P3 and the image data I0 in the frame memory a, and is stored in the buffer memory 24. Next, the image data P6 compressed by the forward inter-frame prediction on the recording medium 20 is decoded and stored in the frame memory a, the image of the image data B2 is displayed, and the image data P6 is compressed by the forward inter-frame prediction of the frame memory b. With reference to the image data P3 and the image data I0 in the frame memory a, the image data B2
Is subjected to data compression by motion compensation bidirectional prediction and stored in the buffer memory 24. Next, the image data B4 compressed by the bidirectional prediction on the recording medium 20 is decoded and stored in the frame memory c, and the image of the image data P3 compressed by the forward interframe prediction is displayed, and the image data of the frame memory a is displayed. With reference to P6, the image data P3 in the frame memory b is subjected to data compression by motion-compensated unidirectional prediction and stored in the buffer memory 24. Hereinafter, similarly, such processing is performed until the image of the image data P9 compressed by the forward inter-frame prediction is displayed.

Here, a data processing procedure for performing reverse reproduction at the time when the display of the image of the image data P9 compressed by the forward inter-frame prediction is completed will be described with reference to FIG.

When the display of the image data P9 compressed by the forward inter-frame prediction is completed, the frame memory A3
The image data stored in No. 4 is three images of image data I12, image data P9, and image data B8.

First, the image data P6 is read from the buffer memory 24, decoded and stored in the frame memory a, and the image of the image data P9 in the frame memory b is displayed. Next, the image data B7 is read from the buffer memory 24, decoded and stored in the frame memory c, and the image of the image data B8 is displayed. Next, buffer memory 2
4, the image data P3 is read, decoded and stored in the frame memory b, and the image of the image data B7 is displayed. Next, the image data B5 is read from the buffer memory 24, decoded and stored in the frame memory c, and the image of the image data P6 is displayed. Next, the image data B4 is read from the buffer memory 24, decoded and stored in the frame memory c, and the image of the image data B5 is displayed. Next, the image data I0 is read from the buffer memory 24, decoded and stored in the frame memory a, and the image of the image data B4 is displayed.

Thereafter, the reverse reproduction is performed by performing such processing until the image of the image data I0 compressed in the frame on the recording medium 20 is displayed.

As described above, the compressed moving picture reproducing apparatus according to the present embodiment comprises decoding means 21a for reading out the compressed coded data from the recording medium 20 on which the moving picture data is coded and recorded and decoding the data. A compressed moving picture reproducing apparatus comprising a frame memory 21b for storing picture data necessary for the decoding and a display means 22 comprising a display 49 for displaying the decoded moving picture data. ,
A reverse encoding unit 23 for performing compression encoding on the moving image data so as to have a reverse reproduction order; a buffer memory 24 for storing image data compressed and encoded by the reverse encoding unit 23; An input data selecting means 25 for selecting the compression-encoded data of the recording medium 20 and the compression-encoded data of the buffer memory 24 is provided.

With this configuration, the moving picture data decoded by the forward reproduction is compression-encoded by the reverse encoding means 23 so as to be in the reverse reproduction order. Are stored in the buffer memory 24, and in the case of reverse reproduction, the compression-encoded moving image data stored in the buffer memory 24 is read in the reverse direction, decoded, and displayed, thereby displaying the data in the reverse order. Playback can be performed.

That is, the moving picture data decoded at the time of forward reproduction is compressed and coded again, and the compressed coded data is stored in the buffer memory 24. At the time of reverse reproduction, the compressed coded data is decoded. Since the playback and display configuration is adopted, the amount of data stored in the buffer memory is reduced as compared with the case where the moving image data itself decoded during forward playback is stored in the buffer memory.
Longer reverse playback can be performed with a smaller capacity buffer memory.

Therefore, the amount of data stored in the buffer memory is smaller than in the conventional case where the image data itself at the time of decoding is stored in the buffer memory, and the capacity of the buffer memory can be reduced as compared with the conventional method. As a result, it is possible to perform reverse reproduction for a longer time in a buffer memory having the same capacity.

In the above embodiment, the handling in the range between the intra-frame compressed image data has been described. However, in the present invention, the handling is performed in the unit between the intra-frame compressed image data. Therefore, a reverse encoding unit 23 for performing compression encoding on the moving image data so as to make the sequence of the reverse reproduction, a buffer memory 24 for storing the image data compressed and encoded by the reverse encoding unit 23
By increasing the number of circuits or increasing the total number of circuits, the addressing of the image data is reversed, and the reproduction in the forward direction and the reverse direction is performed alternately in units between the image data compressed in the frame. The reverse reproduction of the recording medium 20 can be continuously performed.

[0052]

As described above, according to the compressed moving image reproducing apparatus of the present invention, moving image data decoded by forward reproduction in units of intra-frame compressed image data is compression-encoded again. Since the encoded data is stored in a buffer memory and the encoded data is decoded and displayed at the time of reverse reproduction, the decoded moving image data itself at the time of forward reproduction is stored in the buffer memory. As compared with the case where the data is stored in advance, the amount of data stored in the buffer memory is reduced, and the reverse reproduction can be performed for a longer time with a smaller capacity buffer memory. Therefore, even if the capacity of the buffer memory is reduced, long-time reverse reproduction can be performed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an operation principle of a compressed moving image reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a compressed moving image reproducing apparatus according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a data processing procedure of the compressed moving image reproducing apparatus according to one embodiment of the present invention.

FIG. 4 is an explanatory diagram of a data processing procedure for reverse order reproduction of the compressed moving image reproducing apparatus according to one embodiment of the present invention.

FIG. 5 is a block diagram of a conventional compressed moving image reproducing apparatus.

FIG. 6 is a block diagram of a configuration in which a conventional compressed moving image reproducing apparatus can perform reverse reproduction.

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 recording medium 21 a decoding means 21 b frame memory 22 display means 23 reverse coding means 24 buffer memory 25 input data selection means 27 variable length decoder 28 dequantizer 29 inverse DCT calculator 31 motion compensation forward predicted value calculator 32 Motion Compensation Backward Predictor 33 Motion Compensation Bidirectional Predictor 34 Frame Memory A 35 Frame Memory B 39 DCT Calculator 40 Quantizer 41 Variable Length Encoder 42 Motion Compensation Forward Predictor 43 Motion Compensation Backward Predictor 44 Motion Compensation Bidirectional Predictor 49 Display

Claims (1)

(57) [Claims] 1. A decoding means for reading out and decoding compressed encoded data from a recording medium in which moving image data is encoded and recorded, and storing image data necessary for the decoding. A compressed memory reproducing apparatus, comprising: a frame memory for storing the moving image data; and a display unit for displaying the decoded moving image data. Encoding means; a buffer memory for storing the image data compressed and encoded by the reverse encoding means; and input data selecting means for selecting the compressed encoded data of the recording medium and the compressed encoded data of the buffer memory. And a compressed moving picture reproducing apparatus.