JP2001203978A - Moving picture reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moving picture reproducing device which can equalize intervals of output video during trick reproduction and reverse reproduction display. SOLUTION: This device is provided with a read buffer 20 which temporarily holds an arbitrary GOP(group of picture) read out of a recording medium 1 and a transfer switching part 21 which repeatedly read out the GOP temporarily held in the read buffer 20, and inserts and transfers ineffective data (null packet) to a video decoder 8 when a frame to be displayed next is included in a GOP different from a currently displayed frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving picture reproducing apparatus for reading out and decoding digitally compressed moving picture information from an information recording medium such as a hard disk, and more particularly to a moving picture reproducing apparatus such as a frame advance or slow reproduction. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving image reproducing apparatus capable of performing special reproduction in a reverse direction such as special reproduction, frame return, and slow reverse reproduction.

[0002]

2. Description of the Related Art In each broadcasting system of CS / BS / terrestrial broadcasting,
There is a switch from traditional analog broadcasting to digital broadcasting. In this digital broadcasting, it is generally possible to transmit a plurality of channels or a high-resolution broadcast in a small band by performing image compression using the MPEG system.

[0005] Generally, video information compressed by the MPEG system is subdivided into fixed-length packets called transport (TS), multiplexed with audio and program-related information, and transmitted.

In the MPEG system, video information of about 30 frames per second is transferred into a GOP (Group
of Picture). In the GOP, image compression using frame correlation is performed using a small difference between temporally close images, and an intra-frame image (I frame), a forward prediction coded image (P frame), By using a bidirectional predictive coded image (B frame), the problem of the trade-off between the compression ratio and the image quality is solved.

[0005] An I frame encodes an image only from video information in the frame, and can decode an image without referring to information in another frame, but has a characteristic that the compression ratio is low. I have.

In general, only one I frame exists in one GOP, and other P frames and B frames are
Since it is configured by comparison with this frame information, it is decoded first in the GOP.

[0007] The P frame has been encoded by forward prediction, and is prediction image information compared with the previous I or P frame. Although decoding can be performed in the same order as the output order of the reproduced video, the compression ratio generally decreases as compared with the B frame.

The B frame is image information obtained by bidirectional prediction and is predictively coded from two frame information of I or P before and after that. I frame or P
Compared to a frame, the amount of information is generally small, but it is necessary to decode in a different order from the reproduced video in order to refer to a later image in time. Due to the characteristics of each of these frames, it is difficult to reproduce in the backward direction in MPEG image encoding as compared with reproduction in the forward direction.

A moving image recording / reproducing apparatus which enables a digital broadcast stream sent in such a format to be temporarily recorded on a recording medium and reproduced is disclosed in, for example, Japanese Patent Application Laid-Open No. H08-214264. Kaihei 8-223534
Japanese Unexamined Patent Publication (Kokai) No. H11-15064 proposes a technique that enables trick reproduction such as reverse reproduction and frame advance.

[0010] The conventional moving picture reproducing apparatus described therein will be described below with reference to the block diagram of FIG. In FIG. 9, a digital broadcast TS (transport stream) is recorded in advance on a recording medium 1 such as a hard disk that is driven and controlled by a drive control circuit 2.

Generally, in a digital broadcasting TS, video and audio streams of a plurality of channels are subdivided into fixed length (188 bytes) data called TS packets and multiplexed.

In the Index storage unit 4, head position information (index information) of a video GOP in a TS recorded on the recording medium 1 is read in advance and recorded. This Index information includes a digital broadcast TS on a recording medium 1.
Is analyzed when recorded in the. And recorded separately from the TS.

In response to a frame feed instruction from the user, the controller 6 sends an instruction to the READ I / F circuit 3 to read out GOP information including a frame to be decoded, and sends an audio decoder 7 to mute the audio output. Give instructions. The READ I / F circuit 3 receives this instruction, reads out the TS stream for one GOP based on the Index information, and sends it to the DEMUX unit 5.

The DEMUX unit 5 analyzes a TS packet header in the transmitted TS stream and determines a PID (program ID) specified by the controller 6 in advance.
According to the above, TS packets for video, audio, etc. are selected and transmitted to the respective decoders 7 and 8.

At this time, in the DEMUX unit 5, the packet header and the like are removed from the TS packet, and the PES
(Packetized Elemental Stream).

The PES data sent to the video decoder 8 is stored in a video buffer 9 and then transferred to a frame detection circuit 10. The frame detection circuit 10 detects a picture header and a GOP header from the input data, and notifies the controller 6 of the information.

The picture header contains the picture type (I / P / B), TR (temporal reference) indicating the display screen order in the GOP, and the like.

The data that has passed through the frame detection circuit 10 is sent to a decoding circuit 11, where it is decoded into frame data and then written into a frame memory unit 12. Normally, the frame memory unit 12 has at least three frame memories therein.

The controller 6 includes a frame detection circuit 10
When it is determined that the decoded frame is to be displayed in accordance with the picture information notified from, an output frame switching signal is sent to the frame memory unit 12, and this frame data is output as a video output.

If the decoded frame is not to be displayed, the I frame or the P frame is held in the frame memory because it is referred to for decoding another frame, but the B frame is stored in the other memory. , It is discarded from within the frame memory.

In the case of frame-by-frame playback, when a user inputs an instruction, a GOP including frames to be sequentially displayed is displayed.
Is read out and sent to the video decoder 8. On the basis of the picture header information detected by the frame detection circuit 10 in the video decoder 8, the controller 6 searches for a picture header holding a TR indicating the next order of the currently displayed frame.

Until detected, the current display frame is maintained. If detected, the controller 6 issues a display frame switching instruction to the frame memory unit 12 to display this.

In the case of reverse reproduction, the TR of the frame to be displayed
Is realized by the same means as the frame advance except that the frame is smaller (previous) than the currently held frame and is continuously read until a reverse reproduction stop instruction is given from the user. .

[0024]

FIG. 10 shows the positional relationship between GOPs and their decoded frames when GOPs are sequentially transmitted in order to realize frame-by-frame reproduction in the above-mentioned conventional technology. Although FIG. 10 assumes that one GOP is composed of four frames, it is actually composed of about 15 frames.

To perform frame-by-frame playback of each frame, G
When the OP data is sequentially sent, the decoding interval is 5 when decoding the frame in the n-th GOP.
This is a frame, but when moving to a frame in the (n + 1) th GOP, it becomes one frame.

In general, if the number of frames in a GOP is f, the decoding interval in the same GOP is f + 1 frame, but it is one frame when straddling adjacent GOPs. No.

FIG. 11 shows a positional relationship when GOPs are sequentially transmitted in order to perform reverse reproduction. In FIG. 11, the frame interval is three frames when decoding the frame in the n-th GOP, but is seven frames when moving to the (n-1) -th GOP having a further previous frame.

This is also generally expressed by the same G
The decoding interval in the OP is f-1 frame, but when straddling adjacent GOPs, the decoding interval is f + f-1 frame, and the display interval of reverse reproduction is not constant.

The present invention has been made in view of the above-described problems, and has as its object to provide a moving image reproducing apparatus capable of equalizing output images in trick reproduction and reverse reproduction display. Things.

[0030]

Means for Solving the Problems A first invention of the present application is an M
A moving picture reproducing apparatus including a means for reading an arbitrary GOP from a medium on which moving picture information compressed by using the PEG method is recorded, and a decoder for decoding the read GOP into frame data and outputting the frame data. Go, read GO
When performing special playback in the forward direction (frame advance, slow playback, etc.), the temporarily held GOP is repeatedly read out, and the next frame to be displayed is
Means for inserting invalid data and transferring the invalid data to the decoder when the data is included in a GOP different from the currently displayed frame.

Thus, by inserting invalid data between GOPs and transferring them to the decoder, the display interval of decoded frames can be adjusted without changing the configuration on the decoder side.

In the second invention of the present application, the invalid data to be inserted is a null packet. Thus, invalid data (null packet) can be deleted without adding a circuit.

The third invention of the present application is provided with means for counting the number of null packets to be inserted. This makes it possible to arbitrarily set the display interval of the decoded frame.

In the fourth invention of the present application, the number of null packets to be inserted is set to be equal to the size of one GOP. This makes it possible to make the display interval during frame-by-frame playback across GOPs equal to the frame-by-frame advance interval.

According to a fifth aspect of the present invention, there is provided means for reading an arbitrary GOP from a medium in which moving image information (transport stream (TS) or program stream (PS)) compressed by using the MPEG system is recorded. And a decoder for decoding the read GOP into frame data and outputting the frame data, wherein a means for temporarily holding the read GOP and a special playback in the reverse direction (frame return or slow When performing reverse playback, etc.), the temporarily held G
Means for repeatedly reading an OP and extracting only a specific frame when the next frame to be displayed is included in a GOP different from the frame currently being displayed, and transferring the extracted frame to the decoder. .

Thus, by extracting a specific frame from the GOP and transferring it to the decoder, the display interval of the decoded frame can be adjusted without changing the configuration on the decoder side.

According to a sixth aspect of the present invention, the specific frame to be extracted is an I frame. As a result, the display interval at the time of the reverse reproduction over the GOP can be made closer to the reverse reproduction interval at the non-strike.

By making the recording information a transport stream or a program stream, any special reproduction can be performed not only for digital broadcasting but also for moving image information stored in a fixed recording device such as a DVD. Becomes possible.

In the above-mentioned special reproduction, by muting the sound, it is possible to prevent the output of the disturbed sound. Furthermore, during slow playback or slow reverse playback, by automatically repeating the operation until the user instructs to stop, it is possible to continuously provide images such as trick playback without requiring the user to perform troublesome operations. .

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5. The same parts as those in the above-mentioned conventional example are denoted by the same reference numerals, and description thereof will be omitted. still,
In the present embodiment, special reproduction in the forward direction is enabled for an input bit stream, such as frame advance and slow reproduction.

Here, FIG. 1 is a block diagram showing a schematic configuration of the moving picture reproducing apparatus of the present embodiment, FIG. 2 is an explanatory diagram showing a format of Index information in the moving picture reproducing apparatus of the present embodiment, and FIG. FIG. 3 is a block diagram illustrating a configuration of a GOP transfer unit in the moving picture reproduction device of the embodiment.

FIG. 4 is an explanatory diagram showing a null packet format recommended by ITU-T H.222.0, and FIG. 5 is a diagram showing a GOP generated by the moving picture reproducing apparatus of the present embodiment and reproduction included therein. FIG. 4 is an explanatory diagram showing a positional relationship with a frame.

In FIG. 1, a recording medium 1 has a digital broadcast TS (transport stream) recorded in advance. In the Index storage unit 4, head position information (index information) of the video GOP in the TS recorded on the recording medium 1 is read in advance.

The information has, for example, a table format as shown in FIG. 2, and the position of the GOP in the stream is recorded in the table in the number of bytes from the head.

When the controller 22 receives the frame feed instruction from the user input unit 23, if the frame to be displayed next is included in a GOP different from the already read GOP, the controller 22 reads the GOP information so as to read the GOP information. I
An instruction is sent to the / F circuit 3 and an audio output mute instruction is sent to the audio decoder 7.

In the GOP data already read,
If there is a frame to be displayed next, the GOP transfer unit 1
8 only needs to be retransmitted from the read buffer 20 in
There is no need to newly read data from the recording medium 1. R
The EAD I / F circuit 3 receives this instruction, reads the TS stream for one GOP from the recording medium 1 based on the Index information, and sends it to the GOP transfer unit 18.

FIG. 3 shows a specific configuration of the GOP transfer section 18 in the present embodiment. In FIG. 3, reference numeral 24 denotes a switch of a read buffer 20 for temporarily storing an input GOP, reference numeral 21 denotes a switch of a buffer for transfer, and reference numeral 19 denotes a buffer for storing data of a null packet. It is a transfer control unit that operates according to instructions.

The transfer control unit 25 is provided with a counter 26 for counting the number of null packets transmitted. Here, the null packet is defined in ITU-T H.264. 22
A packet recommended in 2.0 and having a PID of 0x1FFF and a payload of 0xFF has a format as shown in FIG.

If the next frame to be displayed is included in the same GOP as the frame currently being displayed, the GOP data has already been stored in the read buffer 20.
The controller 22 instructs the transfer control unit 25 to retransmit the GOP data to the DEMUX unit 5.

The transfer control section 25 sends out data without switching the transfer buffer. Also, the same G
When switching frames within an OP, null packets are not inserted between GOPs.

If the frame to be displayed next is included in a GOP different from the frame currently being displayed, the READ
The GOP data sent from the I / F circuit 3 is written to the read buffer 20. The read buffer 20 is a double buffer, so that data from the READ I / F circuit 3 can be written to the other buffer while one buffer is being transmitted.

Upon receiving a 1 GOP reading completion message from the READ I / F circuit 3, the controller 22
Sends a GOP data transfer instruction to the transfer control unit 25. The transfer control unit 25 operates the read buffer switching unit 24 to switch the input read buffer, and then sets the null packet counter 26 to 0 in order to transmit a null packet.

Next, the transfer buffer switching unit 21 is operated to connect the null packet buffer 19 to the output to the DEMUX unit 5 and start sending null packets. At this time, each time one null packet is transmitted, the null packet counter 26 is incremented by one, and the value is compared with the packet size of one GOP held by the transfer control unit 25.

The packet size of one GOP is a constant set in advance by the controller 22. If the bit stream has a standard resolution (MP @ HL), the packet size is generally 8400.
(For 1.5 Mbytes), or about 1700 (for 300 Kbytes) for high resolution (MP @ ML). SP
(Simple Profile) can be set in the same way.

While the value of the counter 26 is less than the packet size, the null packet transfer is repeated. When the value of the counter 26 becomes equal to the packet size, the input of the transfer buffer switching unit 21 is switched to the read buffer 20, and the corresponding GOP is transferred.

The DEMUX unit 5 analyzes the packet header in the transmitted TS stream, and selects TS packets for video, audio, etc. according to a PID (program ID) specified in advance by the controller 22. Then, the data is transmitted to the respective decoders 7 and 8.

In this embodiment, since invalid data to be inserted between different GOPs is a null packet,
Since the MUX unit 5 automatically discards invalid data, there is no need to add a new circuit.

In the video decoder 8, the controller 22
, And decodes and outputs an arbitrary frame. The configuration for performing frame detection and display switching in the video decoder 8 is the same as that of the video decoder 8 in FIG. 9, and thus description thereof will be omitted.

After frame data is output, in the case of frame advance, the above-described processing is performed again after waiting for the next user input, and during slow playback, the above-described processing is automatically performed until there is a stop input from the user. Repeated.

FIG. 5 shows the positional relationship of frames newly generated during frame-by-frame playback with the above configuration.
It is. In FIG. 5, one GOP is assumed to be four frames, as in the case shown in FIG.

That is, the n-th GOP and the (n + 1) -th GO
By inserting null packets of one GOP (four frames in this case) between P and P, the intervals between the frames to be decoded are made equal to five frames.

In general, the decoding interval across adjacent GOPs is 1 frame before inserting a null packet (FIG. 10) with respect to the number of frames f in the GOP, but becomes f + 1 frame after inserting a null packet. It becomes equal to the decoding interval f + 1 in the same GOP.

Next, a second embodiment of the present invention will be described in detail with reference to FIGS. 6 to 8. The same parts as those in the first embodiment of the present invention are denoted by the same reference numerals, and the description thereof will be omitted. . In the present embodiment, it is possible to perform special reproduction in the reverse direction with respect to the input bit stream, such as reverse reproduction and frame return.

Here, FIG. 6 is a block diagram showing a schematic configuration of the moving picture reproducing apparatus of the present embodiment, FIG. 7 is a block diagram showing a configuration of a GOP transfer section in the moving picture reproducing apparatus of the present embodiment, and FIG. FIG. 3 is an explanatory diagram illustrating a positional relationship between a GOP generated by the moving image reproducing device of the present embodiment and a reproduced frame included therein.

In this embodiment, similarly to the first embodiment, in response to the frame return instruction from the user input unit 23, the controller 32 reads the GOP data including the next frame to be displayed. An instruction is sent to the I / F circuit 3 and the audio decoder 7
To mute the audio output.

In the GOP data already read,
When there is a frame to be displayed next, since the GOP data has already been stored in the read buffer 30 in the GOP transfer unit 28, there is no need to newly read the frame. The read GOP data is sent to the GOP transfer unit 28.

FIG. 7 shows a specific configuration of the GOP transfer unit 28 in the present embodiment. In FIG. 7, reference numeral 33 denotes a read buffer switching unit; 31, a transfer buffer switching unit for setting a buffer to be transferred and its destination; 34, a frame extraction unit for extracting an arbitrary frame; It is a transfer control unit that operates in accordance with it.

If the next frame to be displayed is included in the same GOP as the frame currently being displayed, it is not necessary to operate the read buffer switching section 33 since it has already been read into the read buffer 30. .

The next frame to be displayed is a new GOP
Is included, the transfer control unit 35 operates the read buffer switching unit 33 to switch the input to the currently unused read buffer.

When the next frame to be displayed is the I frame at the head of the GOP, the transfer control unit 35 receives the instruction from the controller 32 and transfers the data from the read buffer 30 to the frame extracting unit 34 so as to send the data. The buffer switching unit 31 is operated.

The GOP data sent to the frame extracting unit 34 is input to the picture header detecting unit 36. The picture header detection unit 36 searches the TS packet having the PID specified in advance by the controller 32 for a picture header, and when the picture header is detected,
Transfers the picture type (I / P / B) information to the transfer control unit 3
Send to 5.

If the detected picture is an I frame, the output data switching unit 37 is connected to the output to the DEMUX unit 5. When a P or B frame is detected, the output data switching unit 37 is switched to a null output 38, and the frame information is discarded.

When the frame to be displayed next is not an I frame, the transfer buffer switching unit 31 is operated so that the output from the read buffer 30 is directly connected to the output to the DEMUX unit 5.

The DEMUX unit 5 analyzes a packet header in the transmitted TS stream, and sorts TS packets for video, audio, etc. according to a PID (program ID) specified in advance by the controller 32. The data is sent to the respective decoders 7 and 8.

In the video decoder 8, the controller 32
, And decodes and outputs an arbitrary frame. The configuration for performing frame detection and display switching in the video decoder 8 is the same as that of the video decoder 8 in FIG. 9, and thus description thereof will be omitted.

After the frame data is output, in the case of frame rewind, the above-described processing is performed again after waiting for the next user input, and in reverse reproduction or reverse slow reproduction, automatically until a stop input from the user is input. The above processing is repeated.

FIG. 8 shows the positional relationship of a frame newly generated at the time of frame return reproduction by the above configuration.
It is. In FIG. 8, as in the case of FIG. 11, one GOP is assumed to be four frames.

That is, the n-th GOP and the (n-1) -th GO
By extracting and transferring only the I-frame in the n-th GOP between P and P, the frame interval to be decoded becomes 4 frames, which is compared with 7 frames in the case where the I-frame extraction is not performed (FIG. 11). Thus, equal spacing is performed.

In general, the decoding interval across adjacent GOPs is 2 * f-1 frames before I frame extraction for the number of frames f in the GOP (FIG. 11).
However, after extraction, the frame becomes f frames, which is close to the decoding interval f-1 in the same GOP.

Note that G in the first and second embodiments described above.
By combining the OP transfer units 28 and 38, it is possible to form one system. In this case, except for the GOP transfer unit, the read buffer, the read buffer switching unit, the transfer buffer switching unit, and the transfer buffer switching unit can be shared within the GOP transfer unit as having the same function.

Further, in the above-described embodiment, only the case where the interval of frame advance or reverse reproduction is one frame is described, but it is also possible to perform trick reproduction at intervals of a plurality of frames. In this case, the controller may set the transfer control unit to an appropriate value for the interval and number of null packet insertion and arbitrary frame extraction at any time.

Furthermore, in the above embodiment, it is assumed that video information is recorded as TS (transport stream), but PS (program stream)
In this case, the same means can be used by reading data from the recording medium in GOP units.

[0083]

According to the first aspect of the present invention, when performing forward special reproduction (frame advance, slow reproduction, etc.),
The temporarily held GOP is repeatedly read, and when the frame to be displayed next is different from the frame currently being displayed, invalid data is inserted and transferred to the decoder. Thus, the display interval of the decoded frame can be adjusted.

According to the second aspect of the present invention, since the invalid data to be inserted is a null packet,
Invalid data (null packet) without adding circuit
Can be deleted.

According to the third aspect of the present invention, since the means for counting the number of null packets to be inserted is provided, the display interval of decoded frames can be set arbitrarily.

According to the fourth aspect of the present invention, the number of null packets to be inserted is set to be equal to the size of one GOP. The interval can be made equal to the frame feed interval that does not straddle.

According to the fifth aspect of the present invention, the temporarily held GOP is repeatedly read out, and when a frame to be displayed next is different from the currently displayed frame, only a specific frame is extracted. Therefore, since the data is transferred to the decoder, the configuration on the decoder side is not changed.
It becomes possible to adjust the display interval of the decoded frame.

According to the invention described in claim 6 of the present application, since the specific frame to be extracted is an I frame, the display interval at the time of reverse reproduction across GOPs can be made closer to the reverse reproduction interval without straddling. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a moving image reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a format of Index information in the first embodiment of the moving image reproducing apparatus of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a GOP transfer unit in the first embodiment of the moving image reproduction device of the present invention.

FIG. 4 is an explanatory diagram showing a format of a null packet recommended in ITU-T H.222.0.

FIG. 5 is an explanatory diagram showing a positional relationship between a GOP generated by the first embodiment of the moving image reproducing apparatus of the present invention and a reproduced frame included therein.

FIG. 6 is a block diagram showing a schematic configuration of a moving image reproducing apparatus according to a second embodiment of the present invention.

FIG. 7 is a block diagram illustrating a configuration of a GOP transfer unit in a second embodiment of the moving picture reproduction device of the present invention.

FIG. 8 is an explanatory diagram showing a positional relationship between a GOP generated by a moving image reproducing apparatus according to a second embodiment of the present invention and a reproduced frame included therein.

FIG. 9 is a block diagram showing a schematic configuration of a conventional moving image reproducing apparatus.

FIG. 10 is an explanatory diagram showing a positional relationship between a GOP transmitted during frame-by-frame playback in a conventional moving image playback apparatus and a playback frame included therein.

FIG. 11 is an explanatory diagram showing a positional relationship between a GOP transmitted at the time of reverse reproduction in a conventional moving image reproducing apparatus and a reproduction frame included therein.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording medium 2 Drive control circuit 3 Read I / F circuit 4 Index storage unit 5 DEMUX unit 7 Audio decoder 8 Video decoder 18 GOP transfer unit 19 Null packet buffer 20 Read buffer 21 Transfer switching unit 22 Controller 23 User input unit 24 Read buffer Switching unit 25 Transfer control unit 26 Null counter 28 GOP transfer unit 30 Read buffer 31 Transfer buffer switching unit 32 Controller 33 Read buffer switching unit 34 Frame extraction unit 35 Transfer control unit 36 Picture header detection unit 37 Output data switching unit 38 Null output

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinichiro Shirai 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Mamoru Oda 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka (72) Inventor Tsuyoshi Hashimoto 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka F-term (reference) 5C053 FA20 FA23 FA24 GB06 GB08 GB11 GB37 HA22 HA23 HA25 HA29 HA33 HA40 JA12 JA21 JA30 KA03 KA08 KA20 KA24 5D044 DE03 DE17 DE28 FG10 GK08 HH05

Claims (6)

[Claims] 1. A system comprising: means for reading an arbitrary GOP from a medium on which moving image information compressed by using the MPEG system is recorded; and a decoder for decoding the read GOP into frame data and outputting the frame data. A moving image reproducing apparatus, comprising: means for temporarily holding the read GOP; and when performing special reproduction in the forward direction, while repeatedly reading the temporarily held GOP, a frame to be displayed next is:
Means for inserting invalid data and transferring the invalid data to the decoder when the data is included in a GOP different from the currently displayed frame. 2. The moving picture reproducing apparatus according to claim 1, wherein the invalid data to be inserted is a null packet. 3. The moving picture reproducing apparatus according to claim 2, further comprising means for counting the number of null packets to be inserted. 4. The number of null packets to be inserted is defined as GO
3. The moving image reproducing apparatus according to claim 2, wherein the size is set to be equal to the size of one P. 5. A system comprising: means for reading an arbitrary GOP from a medium on which moving image information compressed by using the MPEG system is recorded; and a decoder for decoding the read GOP into frame data and outputting the frame data. A moving image reproducing apparatus, comprising: means for temporarily holding a read GOP; and, when performing special reproduction in the reverse direction, repeatedly reading the temporarily held GOP, and setting a frame to be displayed next to:
Means for extracting only a specific frame when the frame is included in a GOP different from the currently displayed frame and transferring the extracted frame to the decoder. 6. The moving image reproducing apparatus according to claim 4, wherein the specific frame to be extracted is an I frame.