JP2002094938A - Data processing method and system, data transmission system, transmission medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data transmission system where a decoding terminal side eliminates the need for preparation of specific data for special reproduction in advance for the purpose of special reproduction and can avoid occurrence of synchronization deviation in transmission data and its accumulation without the need for any special processing for the special reproduction at all, even the decoding terminal whose processing requires entry of data to be processed consecutively at all times can decode the data and the bit rate can be kept constant even during the special reproduction. SOLUTION: A server 10 is provided with: a data conversion section 3 that transmits a plurality of data used by usual reproduction to a decoding terminal 12 when the decoding terminal 12 makes the usual reproduction and applies prescribed conversion processing to data used for special reproduction among a plurality of the data when the decoding terminal 12 makes the special reproduction and transmits the data subjected to the prescribed conversion processing; and a data conversion section 7 that transmits no data that are not used for the special reproduction but transmits dummy data in place of the data that are not used for the special reproduction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to distribution of multimedia data including video data such as still images and moving images, audio data, text data and graphic data through a network, and the distributed multimedia data. The present invention relates to a data processing method and an apparatus, a data transmission system, and a transmission medium that are optimally used when performing trick play in a data distribution system that receives, decodes, and displays the data in a decoding terminal.

[0002]

2. Description of the Related Art A conventional data distribution system in which video data or the like obtained by compressing and storing still and moving image signals is transmitted via a transmission medium, received by a decoding terminal, decoded, and displayed. FIG. 27 shows a configuration example. Note that FIG.
In FIG. 7, only the path of the video data is described to simplify the description. In the following description, video data is stored in, for example, an ISO (International Organization).
for Standardization) / IEC (International Elect)
rotechnical commission) 13818-1 (so-called M
An example is given in which a packet is distributed to a transport stream (hereinafter, simply referred to as a TS) defined in PEG-2 Systems and distributed.

In FIG. 27, a server 200 includes a storage unit 209 for storing video data. The video data read from the storage unit 209 is
At 04, the packet is packetized into a TS, and is further formed as distribution data 211 by the transmission unit 205, output to the transmission medium 210, and distributed to, for example, the decoding terminal 212. At this time, the TS distribution data 211 is transmitted using the protocol used in the transmission medium 210. For example, a TS that satisfies the provisions of ISO / IEC13818-1
IEC61883 "Digital Interface for cons
umer audio / video equipment, for example, IEEE (Institute of Electrical and Electron
cs Engineers) It is possible to transmit using a 1394 standard transmission medium. Note that the multiplexing unit 204 and the transmitting unit 205 may be integrated.

[0004] In the decoding terminal 212, the distribution data 211 is received by the reception unit 213 and sent to the separation unit 214.
The separating unit 214 separates the video data from the TS packet and sends the video data to the decoding unit 215. In the decoding unit 215,
Decode the encoded video data. The decoded video data is sent to, for example, a display device (not shown) and displayed as a video image.

In such a data distribution system,
For example, when performing special playback display such as fast-forward playback or frame-by-frame playback, for example, a special playback designation signal (instruction signal such as fast-forward playback or frame-by-frame playback) according to an operation of a terminal front panel or a remote controller by a user.
206 is a special reproduction control unit 216 of the decoding terminal 212
Will be entered. At this time, the special reproduction control unit 216 of the decoding terminal 212 transmits the special reproduction video data of the type specified by the special reproduction specifying signal 206 to the server 2.
00, a special reproduction request signal 220 for requesting the transmission medium 2 is transmitted.
10 to the special reproduction control unit 201 of the server 200.

[0006] Upon receiving the special reproduction request signal 220, the special reproduction control unit 201 of the server 200 generates control signals 202a and 202b corresponding to the request and sends them to the corresponding multiplexing unit 204 and transmission unit 205, respectively.
The multiplexing unit 204 reads data from the storage unit 209 under the control of the trick play control unit 201 based on the control signal 202b.
The special reproduction of the type specified by the user is performed by the decoding terminal 212.
Reads out video data for special reproduction to enable. The multiplexing unit 204 packetizes the special reproduction video data into a TS and sends the packet to the transmission unit 205. The transmission unit 205 distributes the packet of the special reproduction video data to the decoding terminal 212 as distribution data 211 under the control of the special reproduction control unit 201 by the control signal 202a.

At the decoding terminal 212 when the distribution data 211 composed of the special reproduction video data is supplied, the control signals 217a and 217b for performing the special reproduction control according to the special reproduction designation signal 206 are transmitted to the decoding terminal 212. The data is output from the reproduction control unit 216 and sent to the corresponding receiving unit 213 and decoding unit 215, respectively. Receiver 21
3 receives the distribution data 211 composed of the video data for the special reproduction under the control of the special reproduction control unit 216 based on the control signal 217b, and sends it to the separation unit 214. The separation unit 214 separates the special reproduction video data from the TS packet and sends the special reproduction video data to the decoding unit 215. The decoding unit 215 decodes video data for trick play under the control of the trick play control unit 216 based on the control signal 217a. As a result, a special playback display such as fast-forward playback or frame-forward playback is performed on a display device (not shown).

In the data distribution system described above, for example, ISO / IEC13818-2 (so-called M
An example of distributing compressed video data conforming to PEG-2 video is described, but the ISO / IEC13818 is used.
The compressed video data specified in -2 must be encoded so as not to overflow and underflow the decoder buffer. The decoder buffer corresponds to an input buffer (not shown) provided in the decoding unit 215. This ISO / IEC1381
If data exceeds the size of the buffer specified in 8-2, the decoder buffer overflows. On the other hand, if data necessary for decoding does not arrive at the time to decode, the decoder buffer underflows.

A video frame encoding method defined in ISO / IEC13818-2 includes an I-picture (Intra-code) encoding from only intra-frame data.
d picture: an intra-coded image and a B picture (Bidirectionally) to be coded using inter-frame prediction
There are a predictive-coded picture: a bidirectional predictive coded image) and a P picture (Predictive-coded picture: a forward predictive coded image).

Here, in the data distribution system shown in FIG. 27, the I-picture which does not use the prediction processing between video frames is used as the special reproduction video data read from the storage unit 209. I have. That is, I-pictures are regularly included in video data for normal reproduction to enable random access, and the I-pictures are extracted to form video data for special reproduction. As described above, in the conventional data distribution system shown in FIG. 27, when special decoding such as fast forward is performed in the decoding terminal 212, the ISO /
Video data consisting of only IEC13818-2 I pictures is distributed from the server 200 to the decoding terminal 212.

[0011]

However, the amount of video data consisting of only I pictures increases.
The decoder buffer may overflow or underflow. For this reason, in the conventional data distribution system, special data for special reproduction different from that for normal reproduction is prepared in advance so as to enable special reproduction without overflowing or underflowing the decoder buffer. When performing special reproduction in a decoding terminal, special data for the special reproduction is distributed. In addition, the decoding terminal also needs a special terminal capable of performing special trick-play processing different from normal trick-play processing corresponding to the special data for trick-play.

That is, in the conventional data distribution system, in order to realize the special reproduction without causing the decoder buffer to overflow or underflow, special reproduction different from the above-mentioned special reproduction video data consisting of only I-pictures is required. It is necessary to prepare special data for the special playback in advance, and at the same time, the decoding terminal also needs a special terminal capable of handling the special data for the special reproduction. On the other hand, in a data distribution system that distributes a plurality of multimedia data including video data, audio data, text data, graphic data, and the like as described above, all data is not necessarily decoded or displayed during trick play. Is not required. For example, in general, during fast-forward playback of video data, audio data accompanying the video data need not be played back. Therefore, distribution of data that does not need to be reproduced during special reproduction at the decoding terminal, such as audio data at the time of fast-forward reproduction of the video data, may be stopped.

The timing of data distribution when the distribution of audio data is stopped during special reproduction, for example, will be described with reference to FIG.

D100 and D101 in FIG. 28 indicate timings of video data and audio data distribution when normal reproduction is performed on the decoding terminal side. In the following description, since the display of the image and the sound emission of the sound are related to each other, each time related to the sound emission of the sound is the same as the display start time, the display end time, the display time, and the like of the image display. Use expressions. Note that in some encoding methods such as MPEG-2 video, the display order and the order in which data is encoded in the bit stream may be different, but in the example of FIG. They are shown according to the display order. One display unit in the figure corresponds to a video frame in video data, and data encoding is usually performed for each display unit. This display unit, that is, the coding unit, is hereinafter referred to as AU (access unit).
Call. The display time of one AU generally depends on the encoding method.

On the other hand, D112 and D113 in FIG.
The timing of video data and audio data distribution in the case where a decoding operation that shifts from normal reproduction to special reproduction at time To and returns to normal reproduction at time Ti is performed on the decoding terminal side is shown. In the case of this example, for the distribution video data D112, the AU immediately before the start of the trick play.
106 and later are switched to special reproduction data, and AU1
FIG. 7 illustrates a case where a process for returning to normal playback from 07 is performed. Further, regarding the distribution audio data D113, the AU106 of the video data
From the audio data of the AU 109 corresponding to the AU 107 corresponding to the AU 107 of the video data after the end of the special reproduction.
The distribution is stopped until the audio data of U110. As described above, when the distribution of the audio data is stopped during the special reproduction, a section in which no audio data exists is generated. Hereinafter, a section in which the data is not distributed in this manner is referred to as a gap GP.

As described above, not only the case where the data distribution is intentionally stopped when performing the special reproduction, but also a section where data is lost (the gap GP) occurs when performing the special reproduction. is there. Further, the start and end timings of the trick play are generally determined based on the video display interval. In FIG. 28, the trick play start time To
The trick play end time Ti is determined in accordance with the display timing of a video display unit (video frame). Therefore, if the distribution audio data D11 in FIG.
Even if the data for special reproduction is distributed for the data No. 3 as well as the video data, a gap GP is generated in the audio data because the special reproduction end time is determined depending on the display timing of the video data.

However, depending on the decoding unit provided in the decoding terminal, the gap GP may not be handled in some cases. In particular, in a decoding terminal such as a receiver of a broadcast signal which is premised on input of video data and audio data to be processed continuously, there is a problem that operation when data having a gap GP is input is not guaranteed. is there. That is, in the case of a decoding terminal that is premised on the input of data to be always continuously processed, for example, audio data in which a gap GP exists between AU109 and AU110 as in D113 in FIG. The processing ignoring the gap GP is performed, and the A110 is processed following the AU109. As a result, there is a risk that the reproduction synchronization between the video and the audio may be disrupted. Further, if such a deviation of the reproduction synchronization is accumulated by, for example, a plurality of special reproductions, normal reproduction becomes impossible.

Furthermore, since the display unit after A110 is decoded earlier than the original decoding time, there is a risk that the input buffer provided in the decoding unit of the decoding terminal underflows. Further, depending on the implementation of the decoding unit of the decoding terminal, the gap GP may be regarded as a transmission error with missing data, and the previous display unit may be repeated.

In addition, for example, when a transmission medium to which a transmission band is allocated in advance is used, if a gap GP exists in data to be distributed, the bit rate of the entire distribution data fluctuates. In some cases, it is required to avoid a situation where the bit rate of the entire distribution data fluctuates (it is desired to keep the bit rate of the distribution data constant).

Therefore, the present invention has been made in view of such circumstances, and in order to perform special reproduction on the decoding terminal side, special data for special reproduction different from that for normal reproduction is prepared in advance. It does not require any special processing for special reproduction at the decoding terminal, and can avoid the occurrence of synchronization deviation and accumulation of transmission data. For example, input of data to be processed continuously continuously A data processing method and apparatus that can decode even a decoding terminal that is based on the assumption that the bit rate can be kept constant even during trick play when using a transmission medium to which a transmission band is allocated in advance. , A data transmission system, and a transmission medium.

[0021]

A data processing method according to the present invention is a data processing method for transmitting data coded for each predetermined coding unit to a receiving side. When performing, the plurality of data used for the normal reproduction is transmitted, and when performing the special reproduction on the receiving side, the first data used for the special reproduction among the plurality of data is a predetermined data for the special reproduction. The above-mentioned problem is solved by performing the conversion processing described above and transmitting the second data not used for the special reproduction, by switching to dummy data.

Further, the data processing device of the present invention is a data processing device for transmitting data coded for each predetermined coding unit to a receiving side. When transmitting a plurality of data used for normal reproduction and performing special reproduction on the receiving side, the first data used for the special reproduction among the plurality of data is subjected to a predetermined conversion process for special reproduction. The second data not used for the trick play is transmitted by switching the data to dummy data and transmitted.
The above-mentioned problem is solved.

Next, a data transmission system according to the present invention is a data transmission system comprising a transmitting device for transmitting data encoded for each predetermined coding unit and a receiving device for receiving the data. The device transmits a plurality of data used for the normal reproduction when performing the normal reproduction by the receiving device, and transmits the plurality of data used for the special reproduction when performing the special reproduction by the receiving device. The first data to be transmitted is subjected to a predetermined conversion process for special reproduction and transmitted, and the second data not used for the special reproduction is switched to dummy data and transmitted. Resolve.

Next, the transmission medium of the present invention is a transmission medium for transmitting data coded for each predetermined coding unit by the transmitting device to the receiving device. When a plurality of data used for the normal reproduction is transmitted and the special reproduction is performed in the receiving device,
Data obtained by subjecting the first data used for the special reproduction to the predetermined conversion processing for the special reproduction among the plurality of data is transmitted, and dummy data is used instead of the second data not used for the special reproduction. The above-described problem is solved by being transmitted.

That is, according to the present invention, for example, on the server side, dummy data is output instead of data not used for decoding and display at the time of trick play on the receiving side, and should be decoded and displayed during trick play. Data is converted to data resulting from special reproduction and then delivered. Unnecessary data is not delivered by stopping unnecessary data output for decoding and display. There is no need to determine the data to be decoded and the data not to be decoded and displayed, and the decoding terminal on the receiving side can be configured to require no special reproduction processing. Further, in the present invention, by determining the switching timing of the dummy data based on the reproduction time of the encoding unit, the synchronization deviation between the first and second data is minimized, and the special reproduction is performed a plurality of times. In this case, the accumulation of the synchronization deviation is avoided. Further, according to the present invention, by inserting dummy data into a gap portion, decoding can be performed even on a decoding terminal that is supposed to input video, audio data, and the like that should always be continuously reproduced. Further, according to the present invention, the bit rate can be adjusted even during the trick play by inserting the stuffing data into the dummy data.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

Video data such as still images and moving images, audio data, multimedia data such as text data and graphic data, etc. are distributed via a transmission medium, received by a decoding terminal, decoded, and displayed. FIG. 1 shows a configuration example of a data distribution system according to an embodiment of the present invention. In the following description, video data is stored in, for example, an ISO (International Organization for Standard).
IEC) / IEC (International Electrotechnical)
Commission) 13818-1 (so-called MPEG-2 Sy
transport streams (T
ransport stream (TS) is distributed as a packet.

In FIG. 1, the server 10 includes a storage unit 9 for storing multimedia data such as video data, audio data, text data, graphic data, and the like. For example, video data is read from the storage unit 9, and the video data is sent to the multiplexing unit 4 via the data conversion unit 3 described later, for example. Output data from a data conversion unit 7 described later is also sent to the multiplexing unit 4. The multiplexing unit 4 packetizes the data output from the data conversion units 3 and 7 into TSs as necessary.
This TS packet is further transmitted by the transmitting unit 5 to the distribution data 2.
2 and output to the transmission medium 21 and distributed to the decoding terminal 12, for example. At this time, the distribution data 2 of the TS
2 will be transmitted using the protocol used in the transmission medium 21. For example, ISO / IEC1381
TS that satisfies the requirements of 8-1 is IEC 61883 “Di
gital Interface for consumer audio / video equipmen
t ”, for example, by the IEEE (Institute
f Electrical and Electronics Engineers) It is possible to transmit using a 1394 standard transmission medium. Note that the multiplexing unit 4 and the transmitting unit 5 may have an integrated configuration.

In the decoding terminal 12, the receiving unit 13 receives the distribution data 22 and sends it to the separating unit 14. Separation unit 1
In 4, it separates the video data from the packet of the TS, the desired decoder 15 among the plurality of decoding units 15 ₁ to 15 _n
Send to The decoding unit 15 decodes the supplied data, that is, decodes the encoded video data. The decoded video data is sent to, for example, a display device (not shown) and displayed as a video image. Note that a plurality of decoding terminals 12 may be connected.

When the special reproduction display is performed at the decoding terminal 12 of the data distribution system, for example, a special reproduction designation signal 6 corresponding to an operation by the user of the decoding terminal 12 is transmitted to the decoding terminal 12 shown in FIG. It is transmitted to the server 10 via the transmission medium 21 from a transmission medium interface unit or the like that does not. The special reproduction designation signal 6 is a signal including a type of special reproduction such as fast-forward reproduction, rewind reproduction, frame-forward reproduction, and designation of video data and the like stored in the storage unit 9. If the server 10 and the decoding terminal 12 are connected in a short distance like a home network, for example, and the user can operate a front panel or a remote controller of the server 10, the front of the server 10 By operating a panel, a remote controller, or the like by a user, it is also possible to directly input the trick play designation signal 6 to the server 10.

The special reproduction designating signal 6 input to the server 10 is input to the special reproduction control unit 1 provided in the server 10. The special reproduction control unit 1 generates a special reproduction control signal 2a including a special reproduction type and video data designation according to the special reproduction designation signal 6, and sends the control signal 2a to the data conversion unit 3. Note that the data conversion unit 3
Any number may exist according to the number of data to be distributed.

The data conversion unit 3 controls the control signal 2a
The video data is read out from the storage unit 9 under the control of the trick play control unit 1 by. Further, the data conversion unit 3 uses the video data read from the storage unit 9 and converts the data obtained as a result of performing the special reproduction of the type specified by the control signal 2a, for example, in accordance with ISO / IEC13818-2. Generate and output as video data. That is, at this time, when decoding is performed in the decoding unit 15 of the decoding terminal 12 in the same manner as in normal reproduction, the data conversion unit 3 performs special reproduction (such as fast forward reproduction, rewind reproduction, or frame forward reproduction) (specified by the user). The video data read from the storage unit 9 is converted into video data that realizes (special reproduction). The special reproduction video data (hereinafter, appropriately referred to as converted data) converted by the data conversion unit 3 is transmitted to the decoding terminal 12 via the multiplexing unit 4 and subsequent components as described above. Will be delivered. In addition,
A technique for generating and outputting data resulting from special reproduction using video data read from the storage unit 9 as video data satisfying, for example, ISO / IEC13818-2, as in the data conversion unit 3. The present applicant has already proposed in Japanese Patent Application Nos. 2000-178999 and 2000-179000. An example of the detailed configuration and operation of the data conversion unit 3 will be described later.

That is, according to the present embodiment, the server 1
0, using the video data read from the storage unit 9, the data obtained as a result of performing the special reproduction of the type specified by the special reproduction specifying signal 6 (control signal 2a) is
Generated as video data satisfying the provisions of ISO / IEC13818-2, and the video data (converted data)
Is delivered to the decoding terminal 12, there is no need to use and prepare in advance the special distribution data for special reproduction as in the above-described prior art, and the decoding terminal 12 can use the special distribution data for the special reproduction. It is possible to adopt a simple configuration that does not require a special terminal that can handle the above.

As described above, in a data distribution system that distributes a plurality of multimedia data, it is not always necessary to reproduce all data during special reproduction. During the reproduction, the audio data attached to the video data need not be reproduced. in this case,
For example, if the distribution of data that is not required during special reproduction is stopped, special data for special reproduction different from that for normal reproduction is prepared in advance to perform special reproduction on the decoding terminal side. Therefore, the decoding terminal does not need any special processing for special reproduction.

However, as described with reference to FIG. 28, when the gap GP occurs due to, for example, stopping the distribution of data that is not required during special reproduction, the decoding unit provided in the decoding terminal If the gap GP cannot be handled, the operation when the data having the gap GP is input to the decoding unit is not guaranteed, and for example, there is a possibility that the occurrence of synchronization deviation or accumulation may occur. Further, as described above, the input buffer provided in the decoding unit of the decoding terminal underflows, or the decoding unit of the decoding terminal regards the gap GP as a transmission error due to missing data and repeats the previous display unit. ,
The bit rate of the entire distribution data may fluctuate.

Therefore, in the data distribution system of the present embodiment, distribution of data that does not need to be reproduced during special reproduction in the decoding terminal 21, such as the audio data at the time of fast-forward reproduction of video data, is stopped. At the same time as the gap G
By inserting and distributing dummy data in the P part,
It is possible to avoid occurrence of synchronization deviation of distribution data and its accumulation, for example, decoding can be performed even by a decoding terminal that assumes that data to be continuously processed is input, and further, using a transmission medium to which a transmission band is allocated in advance. In this case, it is possible to keep the bit rate constant even during trick play.

In order to realize this, in the data distribution system according to the present embodiment, for example, when special reproduction is designated, dummy data is output instead of data that does not need to be reproduced during the special reproduction. For this purpose, the data conversion unit 7 is provided in the server 10. Details of the dummy data will be described later.

Hereinafter, the configuration and operation of the data converter 7 will be described. It should be noted that the data that does not need to be reproduced at the time of the special reproduction is not limited to the audio data, but may be, for example, video data. I do.

FIG. 2 shows a detailed configuration of the data conversion unit 7. FIG. 2 shows a server 10 other than the data converter 7.
Are also shown at the same time.

The data conversion unit 7 reads out data (data for normal reproduction) from the storage unit 9 and reads out the data from the storage unit 9.
And a dummy data generation unit 47 for generating dummy data
And a switching unit 18 for switching between data from the reading unit 16 and dummy data from the dummy data generation unit 47. When the dummy data is stored in the storage unit 9 in advance, the dummy data generation unit 47 as an independent configuration becomes unnecessary, and the data conversion unit 7 in this case is integrated with the switching unit 18. The reading unit 16 may switch the data for normal reproduction and the dummy data from the storage unit 9 and read them.
When there are a plurality of data conversion units 7, the read unit 16 in the data conversion unit 7 may have a common configuration for all the data conversion units 7. Further, the switching unit 18 in the data conversion unit 7 may be configured integrally with the multiplexing unit 4 at the subsequent stage.

The switching unit 18 is instructed by the control signal 2b from the trick play control unit 1 to shift to trick play (shift to a data conversion processing state for realizing trick play in the decoding terminal 12). Then, switching is performed so that the dummy data is output by selecting the switched terminal b. On the other hand, when the return to the normal reproduction is commanded, the switched terminal a is selected and the output of the data from the reading unit 16 is restarted. .

The data conversion section 7 in the example of FIG. 2 is also provided with a time information rewriting section 19. The time information rewriting unit 19 encodes time information such as data arrival time, display start time, display end time, display time, or decoding time when encoding and adding the time information to the output data. To the output data. In the case of audio data, each of these time information is actually a time related to sound emission. However, since the display of an image and the sound emission of sound are related, the display start time and the display end time are as described above. , Display time, and the like.
The same applies to the following description.

Next, referring to FIG. 3, the server 10 of the present embodiment switches from normal reproduction to special reproduction and returns from special reproduction to normal reproduction.
One operation example of the data conversion units 3 and 7 will be described.

D10 in FIG. 3 indicates the distribution timing of data output from the data conversion unit 3 and distributed in the case of normal reproduction. Note that MPEG-
In some encoding methods such as 2 video, the display order may be different from the order in which data is encoded in the bit stream. In the example of FIG. Is shown. Also, one display unit in the figure corresponds to a video frame in video data,
Encoding of data is usually performed for each display unit (AU). The display time of one AU generally depends on the encoding method. D11 in the figure represents the distribution timing of data output from the data conversion unit 7 and distributed in the case of normal reproduction.

On the other hand, D12 in FIG.
In the special reproduction control unit 1, the special reproduction control unit 1 controls the special reproduction, and replaces the AU6 and subsequent units immediately before the start of the special reproduction with the conversion data D18 of the special reproduction. This shows the distribution timing when such processing is performed. In this case, the decoding terminal 12 displays the trick play from the display end time To of the AU 6 and the display start time T of the AU 7.
After i, the normal playback display is performed again. D13 in the figure is a dummy data DD in the gap GP portion where the data distribution is stopped in the data converter 7 when the data conversion process for the special reproduction as described above is performed in the data converter 3. Is inserted to indicate the distribution timing when the dummy data DD is distributed.

In this case, for example, double speed reproduction, slow reproduction, or the like is taken as an example of special reproduction, and no conversion processing for special reproduction is performed (ie, normal reproduction).
The relationship between the time t and the time t ′ when the conversion process for the trick play is performed changes every time the trick play is performed. On the other hand, the time Ti
To return to the normal playback section, the AU of data D10
The display must be restarted from the data corresponding to 7. For this reason, the data conversion unit 3 can select the AU 7 corresponding to the special reproduction end time Ti even when performing the data conversion processing for the special reproduction. Further, the correspondence between the time t when the conversion processing is not performed and the time t ′ when the conversion processing is performed is based on the special reproduction end time Ti on the time t ′ when the conversion processing is performed. The value can be calculated by subtracting the display time of the AU 7 on the time t when the processing is not performed, as an offset. Therefore, in the data conversion unit 7,
Data D13 on time t 'when conversion processing is performed
The display time of the AU 10 in the middle is obtained by adding the offset to the display time of the AU 10 in the data D11 on the time t when the conversion process is not performed.

To realize this, the special reproduction control unit 1 notifies the special reproduction start time To or the special reproduction end time Ti to the data conversion unit 7, and sends the offset directly from the data conversion unit 3. Alternatively, it notifies the data conversion unit 7 via the special reproduction control unit 1.

Further, in the case where AU is selected from the input data in the case where the conversion processing is performed, the data conversion unit 7 sets the display time of the AU on the time t when the conversion processing is not performed. When the time information such as the data arrival time, the display start time, the display end time, the display time, or the decoding time is encoded in the output data, the time information rewriting unit 19 performs the above conversion. A value obtained by adding the above offset to the time t ′ when the processing is performed is encoded.

When the time information such as the display start time and the display end time or the display time is encoded in the input data itself, the time information rewriting section 19 of the data conversion section 7
Rewrites the display start time, the display end time, or the display time to the converted value and outputs the converted value. Alternatively, when the time information is added to the data by the multiplexing unit 4, the data conversion unit 7 notifies the multiplexing unit 4 of the change of the time information, and the multiplexing unit 4 transmits the changed time information. It can also be added. Alternatively, when the time information is added to the data by the transmission unit 5, the data conversion unit 7 similarly notifies the transmission unit 5 of the change in the time information, and the transmission unit 5 transmits the changed time information to the data. It can also be added.

As described above, the special reproduction start time T
By knowing the special playback end time Ti and the special playback end time Ti, the data conversion unit 7 determines the switching timing when switching from the normal playback to the special playback and the data D13 in the figure during the special playback.
Thus, the switching timing at the time of returning from the special reproduction to the normal reproduction is realized.

Next, the details of the dummy data DD insertion processing in the data conversion unit 7 when switching from normal reproduction to special reproduction will be described with reference to FIG. FIG.
D11 in FIG. 3 shows an enlarged part of D11 shown in FIG. 3, and D13 in FIG. 4 shows an enlarged part of D13 shown in FIG. In the example of FIG. 4, the time t before the conversion processing for the special reproduction is not performed and the time t ′ when the conversion processing for the special reproduction is performed are not performed earlier. It is assumed that a temporal shift of ΔDTS has occurred due to the trick play. This shift time Δ
The DTS corresponds to a shift in the synchronization relationship between data. The shift time ΔDTS is generated by the trick play in this way because, for example, when processing is performed to shift from the normal play to the trick play and then return from the trick play to the normal play, the start time of the trick play and the The end time is determined depending on the display timing of video data or the like,
This is because the display time of the AU generally differs depending on the encoding method.

As shown in FIG. 4, when switching from normal reproduction to special reproduction is performed, the data conversion unit 7
Based on the trick play start time To, the AU 9 whose display is to be ended before the time To is selected, and the AUs after the selected AU 9 are switched to the dummy data DD and output. As described above, the data conversion unit 7 determines the switching timing of the switching unit 18 so that the dummy data DD corresponding to each AU is output immediately after the AU 9 whose display ends before the special reproduction start time To. I do.
This prevents the decoding terminal 12 from displaying the data for normal reproduction during the special reproduction, etc., and the section pe where the data is replaced with dummy data during the normal reproduction.
Can be minimized.

Next, the details of the process of switching from the dummy data DD to the data for normal reproduction in the data converter 7 when returning from the special reproduction to the normal reproduction will be described with reference to FIGS. D1 in FIGS. 5 and 6
1 is an enlarged view of a part of D11 shown in FIG.
D13a in FIG. 5 is data A for normal reproduction immediately after the dummy data DDa straddling the special reproduction end time Ti.
When switching to U10 is performed, the timing when the difference between the display time of AU10 in data D11 on time t and the display time of AU10 in data D13a on time t 'is ΔDTSa. Represents the same,
D13c in FIG. 6 is the display time of the AU10 in the data D11 on the time t and the data D1 on the time t ′.
ΔDTSc is the time difference from the display time of AU10 in 3c
Represents the timing when. On the other hand, when D13b in FIG. 5 outputs dummy data DDb for another AU after dummy data DDa straddling the special reproduction end time Ti and then switches to the data AU10 for normal reproduction, the time t13b is equal to the time t13. AU10 in data D11 above
In the data D13b at the display time of the
In FIG. 6, D13d in FIG. 6 represents the display time of AU10 in the data D11 on the time t and the data on the time t ′ in the data D11. This represents the timing when the deviation time from the display time of the AU 10 in D13d is ΔDTSd. FIG. 5 shows an example in which ΔDTSa <ΔDTSb, and FIG. 6 shows an example in which ΔDTSc> ΔDTSd.

In the example shown in FIGS. 5 and 6, when switching from the special reproduction to the normal reproduction is performed, the data conversion unit 7 determines the time T based on the special reproduction end time Ti.
The AU 10 whose display is to be started after i is selected, and after the dummy data DDa straddling the special reproduction end time Ti, the AU 10 is switched to the AU data after the selected AU 10 and output.

However, in the case of the example of FIG. 5, the data conversion unit 7 of the present embodiment determines whether the shorter one of the data D13a having the shift time ΔDTSa and the data D13b having the shift time ΔDTSb is shorter. (ΔD
To minimize the TS), the switching timing of the switching unit 18 at the time of transition from the special reproduction to the normal reproduction is selected, that is, ΔDTSa <in the case of the example of FIG.
Because of ΔDTSb, switching unit 1 of data conversion unit 7
At 8, switching is performed at the timing indicated by D13a in FIG.

On the other hand, in the case of the example shown in FIG. 6, the data conversion unit 7 of the present embodiment determines whether the shorter one of the data D13c having the shift time ΔDTSc and the data D13d having the shift time ΔDTSd is shorter. As can be obtained, the switching timing of the switching unit 18 at the time of the transition from the special reproduction to the normal reproduction is selected, that is, in the example of FIG. 6, since ΔDTSc> ΔDTSd, the switching unit 18 of the data conversion unit 7 Switching is performed at a timing indicated by D13d in FIG.

Further, it has been found that, due to human auditory characteristics, a synchronization shift between video and audio data, that is, a shift between video and audio, is more easily perceived when the audio is earlier than the video is later than the video. Therefore, for example, the data output from the data conversion unit 7 is audio data,
As in the case where the data output from the data conversion unit 3 is video data, a synchronization shift between the data is easily perceived (it is easy to perceive that the data output from the data conversion unit 7 is advanced). In such a case, the switching timing can be determined so that the synchronization of the output data from the data converter 7 is always delayed. For example, in FIG. 5, the shift time ΔDTS is minimized by switching to the data for normal reproduction immediately after the dummy data DDa across the special reproduction end time Ti. However, in order to give priority to the direction in which the output timing is delayed, As shown by D13b in FIG. 5, another dummy data DDb may be output after the dummy data DDa that always crosses the special reproduction end time Ti, and then switching to the normal reproduction data may be performed. Of course, on the contrary, when the delay of the data output from the data conversion unit 7 is easily perceived, the switching timing is determined so that the synchronization of the output data from the data conversion unit 7 is always accelerated. It is also possible.

As described above, in the present embodiment, when switching from the normal reproduction data to the dummy data and outputting the data, the dummy data after the special reproduction end time Ti is switched when the dummy data is switched to the normal reproduction. It is possible to minimize the time (ΔDTS) required for switching from the DD to the AU 10 to minimize the synchronization deviation between data. Further, according to the present embodiment, the synchronization shift (ΔDTS in FIG. 4) caused by the previously performed special reproduction as described in the example of FIG. Since it has no effect when switching from the special reproduction to the normal reproduction thereafter, for example, even if the special reproduction is performed a plurality of times, the synchronization deviation due to the plurality of individual reproductions is accumulated. There is no such thing.

Next, as described above, the data converter 7 according to the embodiment of the present invention selects an AU before transition from normal reproduction to special reproduction, and outputs dummy data during the subsequent special reproduction. It has been made like that. However, MPEG-2
When the display order and the encoding order in the encoded data are different because the encoding is performed using the prediction between AUs as in video, an AU that does not break the prediction relationship is selected and then the dummy data is transferred to the dummy data. It is necessary to switch.

The AU selection before shifting from normal reproduction to special reproduction will be described using MPEG-2 video as an example with reference to FIG. Note that the arrow in FIG. 7 indicates the prediction direction, and the original picture of the arrow indicates a predicted picture, and the picture preceding the arrow indicates a predicted picture.

[0061] Here, to display the up I ₃ is an I picture, if you want to switch B ₄ after a B picture to the dummy data, the data conversion unit 7, the position represented by C10 in Fig. 7 in the coding sequence It is sufficient to output the data up to and then switch to dummy data thereafter. Also, to display the up P ₆ is a P-picture, if you want to switch B ₇ after a B picture to the dummy data, the data conversion unit 7 likewise outputs the data to the position represented by C13 in the drawing, Subsequent data may be switched to dummy data. However, C11 in FIG displays up to B ₄ is a B-picture
When considering that such switch the following data to the dummy data, in the encoding order we've been encoded before the P ₆ than B _4. That is, from the data conversion unit 7 to B ₄
Prior to outputting the already P ₆ is too long and the output.
As described above, when the display order and the encoding order in the encoded data are different, the data conversion unit 7 selects an AU at a position where the output can be switched in the encoding order. That is,
For example, in the case of MPEG-2 video, the data conversion unit 7 selects the I or P picture as the last display AU, so that the next I or P picture after the selected I or P picture in the coding order is dummy. You can switch to data.

The data conversion unit 7 according to the embodiment of the present invention
Is designed to select an AU that returns to normal playback and restart the subsequent data output.
MPEG2 defined by eo and ISO13818-7
When encoding is performed using prediction between AUs as in Advanced Audio Coding, an AU that does not break the prediction relationship is selected.

FIG. 8 illustrates the selection of an AU for returning to normal reproduction, using data using forward prediction as an example. In FIG. 8, an AU of intra coding that does not use prediction is denoted by I, and an AU that is coded using forward prediction from a previous AU is denoted by P. The arrow in the figure indicates the prediction direction, and the AU at the original of the arrow indicates the predicted AU, and the AU at the end of the arrow indicates the predicted AU.

According to the example of FIG. 8, since the backward prediction is not used, the display order and the encoding order match. Further, as in the case of C20 and C23 in the figure, if the process returns from the intra-coded AU, the prediction source AU is not lost, and the prediction of subsequent AUs does not fail. Also, C21 and C22 in the figure
When an attempt is made to return from an AU of a P using prediction as in the above, that P and all subsequent Ps cannot be decoded because the prediction source AU is lost. in this way,
When prediction is used, the data conversion unit 7 selects an AU to be returned from intra-coded AUs. Note that the selection of the AU to return when backward prediction is used as in MPEG2 video is the same as that in the data conversion unit 3 described in detail below.

Next, dummy data used in this embodiment will be described.

In the present embodiment, for example, data representing silence can be cited as dummy data inserted in place of audio data, for example, a previous image can be used as dummy data inserted in place of video data. Data indicating repetition (for example, MPEG
2 video), data representing a black image, and the like. Generally, these dummy data can be encoded with a relatively small encoding unit size. In addition, a repeat picture in MPEG-2 video has only to encode a flag indicating that a prediction source image is repeated, since all macroblocks are configured by skip macroblocks, and the size is reduced. As described above, since the encoding size of the dummy data is small, according to the embodiment of the present invention,
By switching to the dummy data during the trick play in the data converter 7, the bit rate of the distribution data can be reduced.

Also, for example, when a transmission medium to which a transmission band is allocated in advance is used and the data GP to be distributed has a gap GP as shown in FIG. 28, the bit rate of the entire distribution data fluctuates. According to the present embodiment, the gap GP
In addition to inserting dummy data into a portion corresponding to, and adding stuffing data to an encoding unit having a small size of the dummy data, the bit rate of the distribution data can be kept constant.

In the data conversion unit 7, instead of adding the stuffing data to the dummy data to keep the bit rate of the distribution data constant, for example, the multiplexing unit 4 at the subsequent stage performs multiplexing using the MPEG2 TS. In this case, it is possible to adjust the bit rate by inserting a null packet (Null packet) defined by the TS of MPEG2 by stuffing. The null packet is discarded in the separation unit 14 of the decoding terminal 12. The stuffing is not limited to the null packet, and any data or packet not used in the decoding process can be used. The transmitting unit 15 may insert the data or packet.

Next, an example of the detailed configuration and operation of the data converter 3 for performing a conversion process on video data, for example, will be described below.

As shown in FIG. 9, the data conversion section 3 includes a reading section 101 for reading video data and insertion data from the storage section 9, a vbv delay detection section 102, a stuffing insertion section 103, and a switching output section 105. It is configured. The insertion data stored in the storage unit 9 is, for example, a repeat picture conforming to the MPEG2 standard. The repeat picture is a picture indicating that the prediction source video data is repeated because all the macroblocks are constituted by skip macroblocks. Here, the insertion data is called repeat data and includes data indicating that it is the same as the prediction source. In particular, in the case of video data, it is called a repeat picture. In this example, a case where only video data and insertion data are stored in the storage unit 9 will be described. However, multimedia data such as still image data, audio data, text data, and graphic data may be used.

The reading unit 101 reads designated video data from the storage unit 9 and reads inserted data from the storage unit 9 in accordance with the control signal 2a from the special reproduction control unit 1. Readout unit 101
Selects and reads out only video data necessary for special reproduction from designated video data according to the type of special reproduction included in the control signal 2a. The reading unit 101 outputs the read video data 110 to the vbv delay detection unit 102, and outputs the read insertion data 111 to the stuffing insertion unit 105.

The vbv delay detection section 102 detects a vbv delay which is information indicating the locus of the bit occupancy of the vbv buffer encoded for each video data.
The vbv delay detection unit 102 includes a read unit 101
Is output to the switching output unit 105, and the detected vbv delay is supplied to the stuffing insertion unit 103.

The stuffing insertion unit 103 performs the following based on the vbv delay from the vbv delay detection unit 102.
The data size of the insertion data is adjusted in order to make the trajectory of the bit occupancy of the vbv buffer continuous. The stuffing insertion unit 103 adjusts the data size of the insertion data by inserting the stuffing data into the insertion data. The stuffing insertion unit 103 outputs the insertion data after adjusting the data size to the switching output unit 105.

For example, when the insertion data is the above-described repeat data, the stuffing insertion unit 103 does not break down the vbv buffer by adding the stuffing data to the repeat data because the data size of the repeat data is smaller than the I picture. Therefore, it is possible to set a desired data size. The data size of a repeat picture when connecting video data is determined by referring to the vbv delay of the video data used for editing. Note that the insertion data may be composed of a plurality of repeat pictures.

The switching output unit 105 switches the video data from the vbv delay detection unit 102 and the insertion data from the stuffing insertion unit 103, and performs the special reproduction according to the control signal 2a from the special reproduction control unit 1. The converted data is output to the multiplexing unit 4. The switching output unit 105 receives video data from the switched terminal b and outputs the video data from the common terminal a, and also receives input data from the switched terminal c and outputs the data from the common terminal a to output video data or insertion data. Is output to the multiplexing unit 4 as conversion data.

Next, when the conversion data for the special reproduction is output in the data conversion unit 3 described above, the switching output unit 105 switches the video data from the video data A to the video data B and outputs the video data. The insertion method will be described.

FIG. 10 shows the locus of the bit occupancy of the video data A in the vbv buffer, and FIG.
5 shows the locus of the bit occupancy of the vbv buffer. Here, an example in which data after frame n in video data A is switched to data after frame m of video data B and output will be described. That is, when frame n-1 of video data A is an out frame, the end point of frame n-1 is an out point, and when frame m of video data B is an in frame, the start point of frame m is an in point. .

According to FIGS. 10 and 11, since the vbv delay of the frame n is different from the vbv delay of the frame m, when the switching is performed by the switching output unit 105, as shown in FIG. The trajectory of the bit occupancy may overflow the buffer size of the vbv buffer or cause an underflow without matching.

On the other hand, when switching the video data, the data conversion unit 3 switches between the frame n and the frame m as shown in FIG. 13 in order to maintain the consistency of the trajectory of the bit occupancy of the vbv buffer. Insertion data is inserted in between, and processing is performed so that the vbv buffer is not broken before and after the switching of the video data.

That is, the vbv delay detector 102
Detects the vbv delay of the video data before and after the switching in order to make the trajectory of the bit occupancy of the vbv buffer continuous when the switching of the video data is performed by the switching output unit 105. On the other hand, the stuffing insertion unit 103 inserts stuffing data into a repeat picture to make the trajectory of the bit occupancy of the vbv buffer continuous, and adjusts the data size of the inserted data. Then, the switching output unit 105 performs switching processing so as to adjust the picture type of the repeat pictures and the number of repeat pictures constituting the insertion data to be inserted between the video data A and the video data B. The data size of the insertion data to be inserted between A and the video data B is determined. Thereby, the switching output unit 105
Outputs to the multiplexing unit 4 conversion data for special reproduction that does not break down the vbv buffer.

Next, the processing of the data conversion unit 3 when the special reproduction specifying signal 6 for specifying the temporary stop as the type of special reproduction is input to the special reproduction control unit 1 will be described.

When the control signal 2a for pausing as a type of special reproduction is input from the special reproduction control unit 1, the data conversion unit 3 inserts insertion data after the out-frame as shown in FIG. To release the stop, the video data returns to the video data after the out-frame.

FIG. 15 shows a processing procedure of the data conversion unit 3 when performing such processing. According to FIG. 15, when the readout unit 101 reads out the video data for normal reproduction, and the control signal 2a for pausing while the transmission data is being transmitted to the decoding terminal 12 is input (step S1). ST11) First, a process of determining an out frame is performed (step ST12). At this time,
The reading unit 101 determines whether the out-frame picture type is an I picture or
It is desirable to select the video data of the picture. Thereby, the reading unit 101 can increase the image quality during the pause.

Next, the data conversion unit 3 inserts the insertion data for a time corresponding to the temporary stop (step ST1).
3) The process of inserting the insertion data is repeated until the control signal 2a for releasing the suspension is input (step ST14).

At this time, the reading section 101 reads out the repeat picture from the storage section 9 as insertion data and outputs it to the stuffing insertion section 103 as data to be displayed on the decoding terminal 12 side during the pause. The stuffing insertion unit 103 sets the reading unit 10 to a data size obtained by multiplying the video data rate by the display interval time of the video frame in order to prevent the breakdown of the vbv buffer.
The stuffing data is added to the repeat picture from No. 1 and output to the switching output unit 105. Switching output unit 105
Outputs the repeat picture from the stuffing insertion unit 103 to the multiplexing unit 4 during the pause.

Here, the stuffing insertion unit 103
Maintain the display order of the pictures before the out-frame by determining the picture type of the repeat picture so that the number of consecutive B-pictures after the out-frame is the same as that during normal playback without pause. Can be.

When the pause is released, the reading unit 101 of the data conversion unit 3 determines the picture type of the first picture after the in-frame (step ST1).
5) If it is determined that the picture is not a B picture, the process returns to normal reproduction as it is (step ST17), and the process ends.
When determining that the picture is a B picture, the reading unit 101 performs a correction process (step ST16). When the picture type of the first picture after the in-frame is not a B picture, the reading unit 101 returns to normal reproduction (step ST17) and ends the process. I do.

The above-described correction processing will be described with reference to an example in which pause processing is performed on video data for normal reproduction in an encoding order and a display order as shown in FIG. In the following description, it is assumed that an arrow in the figure is a motion prediction direction, a frame indicated by the arrow is a prediction destination picture, and a start source of the arrow is a prediction source picture.

The video data for normal reproduction shown in FIG. 16A is data in which frame I ₆ (the I picture whose display order is the sixth) is an out-frame and frame B ₄ is an in-frame. Here, in the video data for normal reproduction, the frame immediately after the in-frame becomes a B picture,
Frame B ₄ and frame B ₅ are frame I ₆ and frame P ₉
Are encoded using predictions from

The repeat picture R (B ₁ ) to repeat picture R (P ₉ ) are inserted between the frame I ₆ and the frame B ₄ by the switching output unit 105, and are used for the special reproduction shown in FIG. When the conversion data is output from the switching output unit 105 to the multiplexing unit 4 as the converted data, the frames B ₄ and B ₅ are decoded by the decoding terminal 12 using the prediction from the repeat picture R (P ₆ ) and the repeat picture R (P ₉ ). Will be decrypted. In such a case, the decoding result of the repeat picture R (P ₉ ) is equal to the frame I ₆ , but the decoding result of the frame P ₃ is different from that of the repeat picture R (P ₆ ), so that the frames B ₄ and B ₅ Cannot be decoded correctly.

On the other hand, in the correction process, the reading unit 105 sets the frame B which is the B picture following the head in the display order after the in-frame as shown in FIG.
_4, the frame B _5, is correctly decoded by inserting the repeat pictures for correction to replace the repeat B picture using only backward prediction. Readout unit 10
1 is a repeat picture R as shown in FIG.
Repeat picture R using only prediction from (P ₉ )
(B ₇ ), repeat picture R (B ₈ ) and frame B ₄ ,
Storage unit 9 inserts data to replace the frame B ₅
The process of reading from is performed. As a result, the decoding terminal 12 can correctly decode the frames B ₄ and B ₅ . Further, the stuffing insertion unit 103 can guarantee that the vbv buffer is not broken by inserting the stuffing data into the repeat pictures R (B ₇ ) and the repeat pictures R (B ₈ ) replaced for correction.

Note that ISO / IEC14496-2 (M
When transmitting video data encoded by an encoding method capable of making the display interval of a picture variable, such as an encoding method defined by PEG-4 video), instead of inserting a repeat picture, By changing the display time of the picture, it is possible to repeat the picture in the special reproduction and to realize the pause.

Next, the processing of the data conversion unit 3 when the special reproduction control signal 1 for specifying fast-forward reproduction as the type of special reproduction is input to the special reproduction control unit 1 will be described.

When the control signal 2a for performing fast-forward reproduction as a type of special reproduction is input from the special reproduction control unit 1, the data conversion unit 3 selects an appropriate I picture from the out-frame and thereafter as shown in FIG. The reading unit 101 is operated to read from the storage unit 9 by
Insertion data is inserted so as not to break down the bv buffer, and when fast-forward playback is released, the video data returns to the video data after the in-frame.

FIG. 18 shows the processing procedure of the data conversion unit 3 when performing such processing. According to FIG. 18, when the read unit 101 reads video data for normal reproduction, and the control signal 2a for performing fast-forward reproduction is being input to the decoding terminal 12 while transmitting the transmission data (step S1). ST21) First, a process of determining an out frame is performed (step ST22). At this time, it is desirable that the reading unit 21 selects video data in which the out-frame picture type is I picture. Accordingly, the reading unit 21 can increase the image quality immediately after the fast forward reproduction.

Next, the reading section 102 selects and reads an I picture or a P picture to be used for fast-forward playback from the video data for normal playback stored in the storage section 9 (step ST23). Here, the reading unit 1
In No. 02, by selecting an I picture, the image quality during fast-forward playback can be increased. Also,
When the fast-forward playback speed is specified by the control signal 2a from the special playback control unit 1, the reading unit 102 adjusts the interval between the selected pictures to adjust the fast-forward playback speed.

Next, the vbv delay detector 102 receives the video data read in step ST23 from the reader 102, and the stuffing inserter 103
The repeat picture (insertion data) read by the reading unit 102 is supplied. The vbv delay detection unit 102 detects the vbv delay using the video data, and the stuffing insertion unit 103 inserts the stuffing data into the repeat picture based on the vbv delay so that the trajectory of the bit occupancy of the vbv buffer is continuous. Output to the output unit 105. Thereby, the switching output unit 1
In step S05, a repeat picture and stuffing data are input to video data as shown in FIG.
T24).

Next, the data converter 3 repeats the processing in step ST23 and the processing in step ST24 until the control signal 2a indicating the cancellation of the fast-forward playback is input and determines that the fast-forward playback is canceled. When the reproduction is canceled, the process proceeds to the next processing (step ST25).

When the fast-forward reproduction is released, the reading section 102 performs a process of selecting an I picture to be used as an in-frame and reading it from the storage section 9 (step ST2).
6), and supply it to the vbv delay detection unit 102.

Next, the vbv delay detecting section 102 detects a vbv delay of video data to be an in-frame from the reading section 102, and outputs a stuffing inserting section 103
Inserts stuffing data based on the vbv delay so as not to break the vbv buffer, and outputs a repeat picture to the switching output unit 105 (step ST2).
7).

Next, the reading unit 102 determines whether or not the selected in-frame video data is the first in the coding order of the closed GOP (step ST28).

When the in-frame video data is the first video data in the coding order of the closed GOP, the reading section 102 returns to the process of reading the video data for normal reproduction (step ST3).
0), and the process ends.

More specifically, when the fast forward reproduction is canceled with the frame I ₂ at the beginning of the closed GOP as shown in FIG. 19A as an in-frame, the repeat picture as shown in FIG. Can be decrypted on the decoding terminal 12 side without inserting.

On the other hand, when the in-frame video data is not the first video data in the coding order of the closed GOP, the reading unit 102 performs a correction process of replacing the video data with a repeat picture having the same data size (step ST29). The process returns to the process of reading the video data for reproduction (step ST30), and the process ends.

More specifically, when the fast forward reproduction is canceled by setting the frame I ₂ which is not the head of the closed GOP as shown in FIG. 20A as an in-frame, as shown in FIG. Since the prediction source picture has been switched for special reproduction, the B picture continuous from the head in the display order cannot be decoded correctly. Here, the reading unit 102 performs corrective processing of replacing the B picture immediately after the in-frame with repeat pictures R (B ₀ ) and R (B ₁ ) using only backward prediction, thereby decoding accurately on the decoding terminal 12 side. Let me do the processing.
Also, the stuffing insertion unit 103 stores the data of the pictures B ₀ and B ₁ before replacement and the repeat pictures R (B ₀ ) and R (B ₁ ) after replacement in order to prevent the breakdown of the vbv buffer. Insert stuffing data so that the sizes are equal.

When performing fast-forward playback, the data conversion unit 3 always makes sure that the in-frame is a closed GOP.
, And so on, unless the in-frame condition determined in step ST26 is particularly different from the picture condition selected in step ST23, the processes in steps ST26 and ST27 are performed in steps ST23 and ST27, respectively. Step ST24
You may go in.

When performing fast-forward reproduction in the reverse direction, the data conversion section 3 selects the I-selection in step ST23.
Processing for arranging the time direction of the picture in the reverse direction is performed.

Next, the processing of the data conversion unit 3 when the special reproduction specifying signal 6 for specifying slow reproduction as the type of special reproduction is input to the special reproduction control unit 1 will be described.

When the control signal 2a for performing slow reproduction as the type of special reproduction is input from the special reproduction control unit 1, the data conversion unit 3 starts the frame of the normal reproduction video data from the out-frame and thereafter as shown in FIG. A process of inserting a repeat picture in between is performed, and when the slow reproduction is released, the video data returns to the video data after the in-frame.

FIG. 22 shows a processing procedure of the data converter 3 when performing such processing. According to FIG. 22, when the readout unit 102 reads out video data for normal reproduction and the control signal 2a for performing slow reproduction is input to the decoding terminal 12 while transmitting the transmission data (step S1). ST41) First, a process of determining an out frame is performed (step ST42).

Here, the video data for normal reproduction is IS
In the case of a TS defined by O / IEC13818-1, the display time information of an I picture or a P picture may be encoded and transmitted prior to the picture data. When the display time is encoded, the out-frame is selected from the I picture or the P picture.

Next, in order to obtain the display time of the current I picture or P picture, the reading unit 102 calculates the number of repeat pictures to be inserted until the next I picture or P picture after starting slow playback. It is determined (step ST43). When it is not necessary to encode the display time, the reading unit 102 does not need to determine the number of insertions in advance. The reading unit 102 controls the speed of slow reproduction based on the number of pictures to be inserted.

Next, the switching output unit 105 performs a process of inserting a repeat picture, which is a B picture, between pictures of video data for normal reproduction (step ST44).
The conversion data for special reproduction decoded as slow reproduction is output to the multiplexing unit 4. At this time, the stuffing insertion unit 103 uses the stuffing data so that the data size of the repeated picture to be inserted is the data size obtained by multiplying the video data rate by the display interval time of the video frame, and does not break down the vbv buffer. I guarantee that. Here, when the display time is encoded, the switching output unit 105 performs control so that slow playback is not canceled until the number of repeat pictures determined in step ST43 is inserted. The accuracy of the displayed time is maintained.

Next, the data conversion unit 3 determines whether or not the control signal 2a for canceling the slow playback has been input from the special playback control unit 1 (step ST45). Is operated by the reading unit 102 so as to read (step ST4).
6) When the processing is terminated and the slow reproduction is not canceled, the processing of the above-mentioned steps ST43 and ST44 is repeated.

Next, the processing of the data conversion unit 3 when a special reproduction specifying signal for specifying jump reproduction as a type of special reproduction is input to the special reproduction control unit 1 will be described.

When the control signal 2a for performing the jump reproduction as the type of the special reproduction is input from the special reproduction control unit 1, the data conversion unit 3 starts the frame of the normal reproduction video data from the out-frame and thereafter as shown in FIG. A process of inserting a repeat picture in between is performed, and the process returns to video data after the in-frame. That is, the server 10
During the transmission of the video data for normal reproduction, the reproduction continues from a different frame of the video data for normal reproduction.

FIG. 24 shows a processing procedure of the data conversion unit 3 when performing such processing. According to FIG. 24, when the control unit 2 reads the video data for normal reproduction by the reading unit 102 and performs the jump reproduction while transmitting the transmission data to the decoding terminal 12 (step S1). ST51) First, the vbv delay detection unit 102 is operated to detect the vbv delay of the frame immediately after the out-frame and the in-frame. At this time, the reading unit 102 reads out the video data of the frame immediately after the out-frame and the in-frame from the storage unit 9 and supplies the video data to the vbv delay detection unit 102, and reads out the repeat picture from the storage unit 9 and supplies the stuffing insertion unit 103 To supply.

Next, the stuffing insertion unit 103 adjusts the data size of the repeat picture by inserting stuffing data based on the detected vbv delay so as not to break the vbv buffer (step ST52).

If the server 10 encodes the display time information before the out-frame before the video data and sends it to the decoding terminal 12, the number of consecutive B pictures after the out-frame jumps. The display order of the pictures before the out-frame is maintained by determining the picture type of the repeat picture so that the number of pictures becomes the same as when the reproduction is not performed.

Next, the reading section 102 determines whether or not the in-frame video data read in the previous step is the head of the closed GOP (step ST5).
3). When determining that the in-frame video data is not the head of the closed GOP, the reading unit 102 performs a correction process of replacing the in-frame video data with a repeat picture having the same data size as in the above-described step ST29 (step ST54), and performs a video for normal reproduction. Returning to the process of reading data (step ST55), the process ends. Thereby, the server 10 can perform jump playback even when
The decoding terminal 12 performs the decoding process accurately, and v
The failure of the bv buffer is prevented.

On the other hand, when the reading section 102 determines that the in-frame video data is the head of the closed GOP, the reading section 102 returns to the processing for reading the video data for normal reproduction (step ST55), and ends the processing.

Next, the processing of the data conversion unit 3 when a special reproduction designation signal for designating frame advance as a type of special reproduction is input to the special reproduction control unit 1 will be described.

When the control signal 2a for frame-by-frame reproduction is input from the special reproduction control unit 1 as a type of special reproduction, the data conversion unit 3 outputs I-pictures at appropriate intervals after the out-frame as shown in FIG. Alternatively, a P picture is selected, the selected picture is replaced with a repeat picture, and the process returns to the video data after the in-frame.

FIG. 26 shows a processing procedure of the data conversion unit 3 when performing such processing. According to FIG. 26, when the readout unit 102 reads out video data for normal reproduction, and the control signal 2a for performing frame-by-frame reproduction during transmission of transmission data to the decoding terminal 12 is input ( Step ST61) First, the reading unit 1
02 performs a process of determining an out-frame (step ST62). Here, the reading unit 102 can select any picture in the video data for normal reproduction as an out-frame. The reading unit 102 can increase the image quality in the in-frame by selecting the I picture as the out-frame.

Next, the reading unit 102 selects an I picture or a P picture (frame-forward playback video data) to be extracted next from the normal playback video data (step ST63). Here, when the P-picture is selected as the frame-by-frame playback video data, if the picture serving as the prediction source of the P-picture has been replaced with a repeat picture, the reading unit 102 decodes correctly on the decoding terminal 12 side. Therefore, a process of reading frame-by-frame playback video data from the storage unit 9 is performed so as to satisfy a condition that an I picture or a P picture immediately before a selected P picture is not replaced with a repeat picture. In addition, the reading unit 102 selects an I picture as frame-by-frame playback video data in order to increase the image quality during frame-by-frame playback.

Further, the reading section 102 performs a process of reading a repeat picture from the storage section 9. At this time, by selecting the number of repeat pictures, the reading unit 102 adjusts the interval between the video data for frame-by-frame playback, and controls the length of time to advance for each picture.

The reading section 102 supplies the video data for frame-by-frame playback read in this processing to the vbv delay detecting section 102 and supplies the repeat picture to the stuffing inserting section 103.

Next, the data conversion section 3 performs a process of replacing all the video data for frame advance reproduction selected in the previous step with a repeat picture (step ST6).
4). When the original picture of the video data for normal reproduction is an I picture or a P picture, the reading unit 102
A read picture is read from the read section 102 so as to be replaced with a repeat picture composed of pictures, and when the original picture is a B picture, the read section 102 is replaced with a repeat picture composed of B pictures.
Reads a repeat picture from. Thereby, the data conversion unit 3 can maintain the display order for each picture type. Also, the stuffing insertion unit 103
Adds stuffing data to a repeat picture so that the data size of the repeat picture is equal to the picture before replacement in order to ensure that the vbv buffer is not broken.

Next, the data converter 3 receives the control signal 2a indicating the cancellation of the frame-by-frame playback and inputs the control signal 2a to determine that the frame-by-frame playback is to be canceled.
3 and the process at step ST64 are repeated to release frame-by-frame playback, the process proceeds to the next process (step ST65).

When the frame-by-frame playback is released, the reading section 102 determines whether or not the I picture or P picture immediately before the in-frame has been replaced by a repeat picture (step ST66). It returns to the process of reading the video data for use (step ST69), and ends the process.

On the other hand, when it is determined that the replacement has been performed, the reading unit 102 performs the same processing as in the above-described steps ST28 and ST29. That is, the reading unit 102 determines whether or not the selected in-frame video data is the head in the closed GOP encoding order (step ST67), and determines that the in-frame video data is the closed GOP encoding order. If it is determined that the data is the head of the process, the process returns to the process of reading the video data for normal reproduction (step ST69), and the process ends. When the video data to be the in-frame is not the first video data in the coding order of the closed GOP, the reading unit 102 performs a correction process of replacing the video data with a repeat picture having the same data size (step ST68). Returning to the process of reading video data (step ST69), the process ends.

When the control signal 2a for performing frame-forward playback at a frame-speed playback speed other than the normal-speed playback is input, the data converter 3 determines the interval between I-pictures or P-pictures selected in step ST63. Adjust the number of repeat pictures to widen. At this time, the data conversion unit 3 performs a process of thinning out the repeat pictures replaced in step ST64 or a process of further inserting the repeat pictures. In addition, the data conversion unit 3 determines the data size of the repeat picture in the same manner as in the case described in step ST24.

Further, when the control signal 2a for performing the frame forward reproduction in the reverse direction is input, the data conversion unit 3 performs processing for arranging the time direction of the I picture selected in step ST63 in the reverse direction.

In such a server 10, even when transmitting the converted data for trick play to the decoding terminal 12, the number of pictures and the data size are adjusted according to the kind of trick play, and the repeat picture is inserted. Conversion data for special reproduction in the same data format as the video data for use.

According to such a data distribution system,
Even when performing the special reproduction, the conversion data for the special reproduction converted by the data conversion unit 3 is converted into the same video data format as that of the normal reproduction. No special reception processing or decoding processing is required for the decoding, and no special reproduction control device is required on the decoding terminal 12 side.

Further, according to the data distribution system described above, for example, when ISO / IEC13818-2 is used, when data is converted by the data conversion unit 3 into data for special reproduction for performing special reproduction. By performing control processing for outputting converted data for trick play that does not break down the vbv buffer, the decoding terminal 12 can have a simple configuration that does not require special processing for trick play.

Further, the server 10 having the data conversion unit 3
According to, even when performing special playback, since it is converted to the same video data format as when performing normal playback,
There is no need to have a function to create a special data format for trick play. The server 10 is, for example, an ISO / IEC13
Even when data is transmitted from the TS specified in 818-1 by the method specified in IEC61883 using the IEEE 1394 cable as the transmission medium 20, vbv
Since the video data is converted into video data that does not cause the buffer to fail, T that satisfies the provisions of ISO / IEC13818-1
S can be multiplexed, and data can be transmitted in a data format that meets the requirements of IEC61883.

Therefore, according to the data distribution system, it is not necessary to combine a special server and a decoding terminal when transmitting data for special reproduction.

Furthermore, according to this data distribution system,
Since there is no need to perform decoding and re-encoding when video data is transmitted by the server 10, the configuration of the data conversion unit 3 can be simplified, and processing delay at the time of transmission can be reduced. There is no degradation of image quality.

The present invention is effective regardless of the type of data such as video data such as still images and moving images, audio data, text data and graphic data, and is applicable to any data encoding method. Further, the present invention can be realized by hardware or software.

[0141]

According to the present invention, when performing normal reproduction on the receiving side, a plurality of data used for the normal reproduction is transmitted, and when performing special reproduction on the receiving side, the first data used for the special reproduction is transmitted. Is transmitted after performing a predetermined conversion process for trick play, and by switching the second data not used for trick play to dummy data and performing trick play on the decoding terminal side. Eliminates the need to prepare special data for different special reproduction in advance, and does not require any special processing for special reproduction in the decoding terminal. For example, decoding can be performed even with a decoding terminal that assumes that data to be continuously processed is always input, and furthermore, when a transmission medium to which a transmission band is allocated in advance is used. It is possible to maintain a constant bit rate even during special reproduction.

Further, in the present invention, by determining the switching timing of the dummy data based on the reproduction time of the coding unit, the synchronization deviation between the first and second data is minimized, Even in the case of performing the trick play, data conversion that does not cause accumulation of a synchronization shift can be performed.

Further, in the present invention, by making it possible to determine the switching timing so that the data synchronization is always in the direction of delaying, the data conversion in which the synchronization shift is hardly perceived due to, for example, human auditory characteristics is realized. It is possible.

Further, in the present invention, when the encoding method using prediction is adopted, the dummy data is switched at a timing that does not break the prediction relationship, so that the start of special reproduction and the Even near the end, it is possible to prevent the decoding process from breaking down.

In the present invention, the size of the dummy data is generally small, so that the bit rate of the output data can be adjusted by inserting stuffing.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a data distribution system according to an embodiment of the present invention.

FIG. 2 is a block diagram used to explain the configuration of a data conversion unit capable of inserting dummy data during special reproduction.

FIG. 3 is a diagram used to explain an example of data conversion in which dummy data is inserted during special reproduction.

FIG. 4 is a diagram used for detailed description of dummy data insertion processing when switching from normal reproduction to special reproduction.

FIG. 5 is a diagram showing a case where switching from special reproduction to normal reproduction is performed.
FIG. 9 is a diagram used for describing an example of a switching timing.

FIG. 6 shows a state in which a special reproduction is switched to a normal reproduction.
FIG. 14 is a diagram used for describing another example of the switching timing.

FIG. 7 is a diagram used to explain AU selection before shifting to trick play, using MPEG2 video as an example.

FIG. 8 is a diagram used to explain AU selection when returning to normal reproduction for data using forward prediction.

FIG. 9 is a block diagram illustrating a configuration example of a data converter for video data.

FIG. 10 is a diagram illustrating a locus of bit occupancy of a vbv buffer for video data A;

11 is a diagram illustrating a locus of bit occupancy of a vbv buffer for video data B. FIG.

FIG. 12 is a diagram showing a locus of bit occupancy of a vbv buffer when switching from video data A to video data B;

FIG. 13 is a diagram illustrating a locus of bit occupancy of a vbv buffer when a repeat picture is inserted between video data A and video data B.

FIG. 14 is a diagram for explaining a process when the data conversion unit for video data pauses.

FIG. 15 is a flowchart for describing a processing procedure when a pause is performed by a data converter for video data.

FIG. 16 is a diagram for describing a correction process when a pause is performed by a data converter for video data.

FIG. 17 is a diagram for describing processing when fast-forward playback is performed by a data converter for video data.

FIG. 18 is a flowchart for explaining a processing procedure when fast-forward playback is performed by a data converter for video data.

FIG. 19 is a diagram for describing an example when fast-forward playback is performed by a data converter for video data.

FIG. 20 is a diagram for describing a correction process when fast-forward playback is performed by a data converter for video data.

FIG. 21 is a diagram for describing processing when slow data is reproduced by a data converter for video data.

FIG. 22 is a flowchart for describing a processing procedure when performing slow reproduction by a data converter for video data.

FIG. 23 is a diagram for describing processing when a jump is performed by the data converter for video data.

FIG. 24 is a flowchart illustrating a processing procedure when a jump is performed by a data converter for video data.

FIG. 25 is a diagram for explaining processing when frame-by-frame playback is performed by a data converter for video data.

FIG. 26 is a flowchart for explaining a processing procedure when frame-by-frame playback is performed by a data converter for video data.

FIG. 27 is a block diagram illustrating a configuration example of a conventional data distribution system.

FIG. 28 is a diagram used to explain a problem when a gap occurs due to a stop of data distribution during special reproduction.

[Explanation of symbols]

1 Special playback control unit, 3,7 Data conversion unit, 4
Multiplexing section, 5 transmitting section, 9 storing section, 10 server, 12 decoding terminal, 13 receiving section, 14 separating section, 15 decoding section, 16 reading section, 18 switching section, 19 time information rewriting section, 47 dummy data generating section

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoichi Yagasaki 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Yoshiaki Oishi 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F term (reference) BD02 BD07 BD08

Claims (46)

[Claims] 1. A data processing method for transmitting data encoded for each predetermined encoding unit to a receiving side, wherein when performing normal reproduction on the receiving side, a plurality of data used for the normal reproduction are transmitted. When performing the special reproduction on the receiving side, the first data used for the special reproduction of the plurality of data is transmitted after performing a predetermined conversion process for the special reproduction and transmitted to the special reproduction. A data processing method characterized by switching unused second data to dummy data for transmission. 2. When shifting from the normal reproduction to the special reproduction, the second reproduction is started from the coding unit after the coding unit for ending the normal reproduction immediately before the time when the special reproduction is started.
2. The data processing method according to claim 1, wherein said data is switched to dummy data. 3. When the special reproduction is shifted to the normal reproduction, the dummy data is switched to the second data from the coding unit having the latest reproduction time after the time when the special reproduction ends. 2. The data processing method according to claim 1, wherein: 4. When shifting from the special reproduction to the normal reproduction, the dummy data is switched to the second data from the coding unit of the dummy data reproduced beyond the time at which the special reproduction ends. 2. The data processing method according to claim 1, wherein: 5. When shifting from the special reproduction to the normal reproduction, the synchronization shift direction between the reproduction start time of the encoding unit of the second data and the reproduction start time of the encoding unit of the first data is set as: The dummy data is switched to the second data so that the reproduction start time of the encoding unit of the second data is always delayed from the reproduction start time of the encoding unit of the first data. 2. The data processing method according to claim 1, wherein: 6. The switching to the second data from a coding unit of dummy data next to a coding unit of dummy data reproduced over a time at which the special reproduction is completed is performed. The data processing method according to claim 5, wherein 7. When the encoding unit immediately before the transition from the normal reproduction to the special reproduction is selected, if the reproduction order is different from the encoding order in the encoded data, the switching can be performed in the encoding order. 2. The data processing method according to claim 1, wherein a coding unit at a proper position is selected. 8. When selecting a coding unit for shifting from the special reproduction to the normal reproduction, a head coding unit for shifting to the normal reproduction is selected from intra-coded coding units. 2. The data processing method according to claim 1, wherein 9. The data processing method according to claim 1, wherein time information relating to transmission and reproduction of the coding unit after the predetermined conversion processing is added to the data. 10. A value obtained by subtracting the reproduction time on the time when the conversion processing is not performed for the encoding unit corresponding to the time from the special reproduction end time on the time when the conversion processing is performed is set as the offset. , By adding to the time information when the above conversion processing is not performed,
10. The data processing method according to claim 9, wherein time information when the up conversion processing is performed is calculated. 11. The time information related to transmission and reproduction of the coding unit before the predetermined conversion processing is corrected to time information related to transmission and reproduction of the coding unit after the predetermined conversion processing, and 2. The data processing method according to claim 1, wherein the data is added inside. 12. The data processing method according to claim 1, wherein stuffing data is inserted on said dummy data to adjust a bit rate of output data. 13. The data processing method according to claim 1, wherein when the second data is audio data, the dummy data is audio data representing silence. 14. The data processing method according to claim 1, wherein when the second data is video data, the dummy data is video data indicating that a previous image is repeated. 15. The data processing method according to claim 1, wherein when the second data is video data, the dummy data is video data representing a black image. 16. A data processing apparatus for transmitting data encoded for each predetermined encoding unit to a receiving side, wherein when performing normal reproduction on the receiving side, a plurality of data used for the normal reproduction are transmitted. When performing the special reproduction on the receiving side when transmitting, the first data used for the special reproduction among the plurality of data is subjected to a predetermined conversion process for the special reproduction and transmitted, and is transmitted to the special reproduction. 2nd not used
A data conversion means for switching the data to dummy data and transmitting the dummy data. 17. The data conversion means, when shifting from the normal reproduction to the special reproduction, from the coding unit after the coding unit for ending the normal reproduction immediately before the time when the special reproduction is started, 17. The data processing device according to claim 16, wherein the second data is switched to dummy data. 18. The data conversion means, when shifting from the special reproduction to the normal reproduction, converts the dummy data from the coding unit having the latest reproduction time after the time at which the special reproduction ends, to the second data. 17. The data processing apparatus according to claim 16, wherein the data processing is switched to data. 19. The data conversion means, when shifting from the special reproduction to the normal reproduction, converts the dummy data from the coding unit of the dummy data reproduced beyond the time at which the special reproduction is completed. 17. The data processing device according to claim 16, wherein switching to the second data is performed. 20. The data conversion means, when shifting from the special reproduction to the normal reproduction, a reproduction start time of a coding unit of the second data and a reproduction start time of a coding unit of the first data. The dummy data is synchronized with the second data so that the reproduction start time of the encoding unit of the second data is always delayed from the reproduction start time of the encoding unit of the first data. 17. The data processing apparatus according to claim 16, wherein the data processing is switched to data. 21. The data conversion means for switching to the second data from the encoding unit of the dummy data next to the encoding unit of the dummy data reproduced over the time at which the trick play ends. The data processing apparatus according to claim 20, wherein the data processing is performed. 22. The data conversion means, when selecting an encoding unit immediately before shifting from the normal reproduction to the special reproduction, when the reproduction order and the encoding order in the encoded data are different, the encoding order 17. The data processing apparatus according to claim 16, wherein a coding unit at a position where the switching can be performed is selected. 23. The data conversion means, when selecting an encoding unit to shift from the special reproduction to the normal reproduction, sets a head encoding unit at the time of transition to the normal reproduction to an intra-coded code. 17. The data processing device according to claim 16, wherein the data processing device is selected from the conversion units. 24. The data processing apparatus according to claim 16, further comprising time information processing means for adding time information on transmission and reproduction of said coding unit after said predetermined conversion processing to said data. . 25. The time information processing means, from the special reproduction end time on the time when the conversion processing is performed, the reproduction time on the time when the conversion processing is not performed on the encoding unit corresponding to the time. 25. The data processing apparatus according to claim 24, wherein a value obtained by subtracting the above is used as an offset and added to time information when the conversion processing is not performed, thereby calculating time information when the upward conversion processing is performed. 26. A method according to claim 26, further comprising the step of correcting time information relating to transmission and reproduction of said coding unit before said predetermined conversion processing to time information relating to transmission and reproduction of said coding unit after said predetermined conversion processing, and 17. The data processing apparatus according to claim 16, further comprising a time information processing unit added to the inside. 27. The data processing apparatus according to claim 16, wherein said data conversion means adjusts a bit rate of output data by inserting stuffing data on said dummy data. 28. The data processing apparatus according to claim 16, wherein when the second data is audio data, the data conversion means generates audio data representing silence as the dummy data. 29. The data processing apparatus according to claim 16, wherein when the second data is video data, the data conversion means generates video data representing repetition of a previous image as the dummy data. Data processing device. 30. The data processing apparatus according to claim 16, wherein when the second data is video data, the data conversion means generates video data representing a black image as the dummy data. 31. A data transmission system comprising a transmitting device for transmitting data encoded for each predetermined coding unit and a receiving device for receiving the data, wherein the transmitting device normally reproduces the data by the receiving device. When performing, to transmit a plurality of data used for the normal playback,
When performing the special reproduction in the receiving device, the first data used for the special reproduction among the plurality of data is subjected to a predetermined conversion process for the special reproduction and transmitted, and the first data not used for the special reproduction is transmitted. 2. A data transmission system comprising: data conversion means for switching data of No. 2 to dummy data for transmission. 32. The data conversion means, when shifting from the normal reproduction to the special reproduction, from the coding unit after the coding unit for ending the normal reproduction immediately before the time at which the special reproduction is started, The data transmission system according to claim 31, wherein the second data is switched to dummy data. 33. The data conversion means, when shifting from the special reproduction to the normal reproduction, converts the dummy data from the coding unit having the latest reproduction time after the time at which the special reproduction ends, to the second data. The data transmission system according to claim 31, wherein the data transmission is switched to data. 34. The data conversion means, when shifting from the special reproduction to the normal reproduction, converts the dummy data from the coding unit of the dummy data reproduced beyond the time at which the special reproduction is completed. The data transmission system according to claim 31, wherein the data transmission system switches to the second data. 35. The data conversion means, when shifting from the special reproduction to the normal reproduction, a reproduction start time of an encoding unit of the second data and a reproduction start time of an encoding unit of the first data. The dummy data is synchronized with the second data so that the reproduction start time of the encoding unit of the second data is always delayed from the reproduction start time of the encoding unit of the first data. The data transmission system according to claim 31, wherein the data transmission is switched to data. 36. The data conversion means switches from the encoding unit of the dummy data next to the encoding unit of the dummy data reproduced beyond the time at which the trick play ends to the second data. The data transmission system according to claim 35, wherein the data transmission is performed. 37. The data conversion means, when selecting a coding unit immediately before shifting from the normal reproduction to the special reproduction, when the reproduction order and the encoding order in the encoded data are different, the encoding order 32. The data transmission system according to claim 31, wherein a coding unit at a position where the switching is possible is selected. 38. The data conversion means, when selecting an encoding unit to shift from the special reproduction to the normal reproduction, sets a head encoding unit at the time of the transition to the normal reproduction to an intra-encoded code. 32. The data transmission system according to claim 31, wherein the data transmission system is selected from the conversion units. 39. The transmission apparatus according to claim 31, further comprising time information processing means for adding time information relating to transmission and reproduction of the coding unit after the predetermined conversion processing to the data. Data transmission system as described. 40. The time information processing means calculates a reproduction time on the time when the conversion processing is not performed on the encoding unit corresponding to the time from the special reproduction end time on the time when the conversion processing is performed. 40. The data transmission system according to claim 39, wherein a value obtained by subtracting is used as an offset and added to time information when the conversion process is not performed, thereby calculating time information when the up-conversion process is performed. 41. The transmission device corrects time information on transmission and reproduction of the coding unit before the predetermined conversion processing to time information on transmission and reproduction of the coding unit after the predetermined conversion processing. 32. The data transmission system according to claim 31, further comprising time information processing means for adding the time information to the data. 42. The data transmission system according to claim 31, wherein said data conversion means adjusts a bit rate of output data by inserting stuffing data on said dummy data. 43. The data transmission system according to claim 31, wherein when the second data is audio data, the data conversion means generates audio data representing silence as the dummy data. 44. The data processing apparatus according to claim 31, wherein, when the second data is video data, the data conversion means generates video data representing repetition of a previous image as the dummy data. Data transmission system. 45. The data transmission system according to claim 31, wherein when the second data is video data, the data conversion means generates video data representing a black image as the dummy data. 46. In a transmission medium for transmitting data coded for each predetermined coding unit by a transmission device to a reception device, when the normal reproduction is performed by the reception device, a plurality of data used for the normal reproduction are used. Data is transmitted, and when performing special reproduction in the receiving device, data obtained by performing a predetermined conversion process for special reproduction on the first data used for the special reproduction among the plurality of data is transmitted; A transmission medium, wherein dummy data is transmitted instead of the second data not used for the trick play.