JP2000232435A - Data stream switching device/method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data stream switching device with less noise when switched. SOLUTION: The device 10 is provided with two input buffers 12 and 14, three change-over switches 16, 18 and 20, a sequence buffer 22, a dummy picture generation part 24, a re-stamping processing part 26, an output buffer 28 and a control part 30. The sequence buffer 22 stores video streams for respective sequences. The control part 30 stops the video streams inputted to the input buffer 14 in a sequence unit and outputs data in the input buffer 12 following the output of data in the sequence buffer 22. At that time, the re-stamping processing part re-stamps PTS(presentation time stamp) and a dummy picture is inserted from the dummy picture generation part 24 if need be.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data stream switching device and a data stream switching method.

[0002]

2. Description of the Related Art There is known a data stream switching device which inputs two data streams, switches these two data streams as appropriate, and outputs one of them. By using such a data stream switching device,
Data streams transmitted from a plurality of partners can be appropriately switched and output.

[0003]

However, the above-mentioned conventional data stream switching device has the following problems. That is, if the input data stream is a simple sequence of data, even if the two data streams are switched at any time, the switched data stream is output and reproduced without any problem.

On the other hand, when an input data stream is formed by arranging a plurality of data strings having a certain unity, the respective data strings are often combined and compressed according to a predetermined method. . Therefore, if two data streams are switched at any time, the switched data stream does not conform to the above-mentioned predetermined method, large noise occurs at the time of switching, and it becomes difficult to reproduce the switched data stream. . For example, even if an attempt is made to switch between two data streams (a data stream formed by arranging a plurality of sequences) compressed by the MPEG method at an arbitrary point in time, the data stream after the switching does not conform to the syntax of the MPEG method. Large noise is generated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and to provide a data stream switching apparatus and a data stream switching method which generate less noise when switching between two data streams each having a plurality of data strings arranged. As an issue.

[0006]

In order to solve the above problems, a data stream switching device according to the present invention inputs two data streams in which a plurality of data strings are arranged, and switches between the two data streams. A data stream switching device for outputting either one of the data streams, comprising a storage means for storing the first data stream for each data sequence, when switching the output from the second data stream to the first data stream. After stopping the output of the second data stream in units of a data stream, following the output of the data stream of the first data stream stored in the storage unit, the input of the first data stream is stopped. It is characterized by outputting a data stream.

When the output of the data stream is switched, the output of the second data stream before switching is stopped in units of a data string, so that the second data stream is switched to the data string as usual (the switching is not performed). Output reproduction is performed (as in the case). Further, the first data stream is stored for each data stream, and after the output of the second data stream is stopped, the stored data stream of the first data stream is first output, and subsequently, the input By outputting the obtained first data stream, the first data stream is output from the beginning of a certain data sequence following the output of the second data stream. Therefore, no information is lost in the data string,
The first data stream after the switching is also performed after the data sequence,
Output reproduction is performed as usual.

Here, in the data stream switching device of the present invention, the first data stream and the second
Are data streams compressed by the MPEG system, and the data sequence may be a sequence including a sequence header as a header portion and a GOP as a data portion.

Further, in the data stream switching device of the present invention, the first data stream is converted from the second data stream.
When the output is switched to the data stream of the first data stream, the first time information associated with each data string of the first data stream and the second time information associated with each data string of the second data stream May be configured to compensate for the difference.

By compensating for the difference between the first time information and the second time information, even if the first time information and the second time information are different, the first data after the switching is changed. It is possible to output and reproduce the stream continuously to the second data stream before switching.

Here, in the data stream switching device of the present invention, the first data stream and the second
Are the data streams compressed by the MPEG system, and the first time information and the second time information are time reference values, respectively.
When switching the output from the second data stream to the first data stream, a difference between the first time information and the second time information may be added to the first time information.

Further, in the data stream switching device according to the present invention, the first decoding delay time for decoding the data string of the first data stream is equal to the delay time for decoding the data string of the second data stream. If the second decoding delay time is shorter than the second decoding delay time,
When switching the output from the data stream to the first data stream, the output of the first data stream may be delayed by a difference between the second decoding delay time and the first decoding delay time. Good.

[0013] By delaying the output of the first data stream by the difference between the second decoding delay time and the first decoding delay time, when the first decoding delay time is shorter than the second decoding delay time. Even if there is, the decoding time of the data string of the second data stream output last can be secured. Therefore, the data stream of the second data stream is output and reproduced as usual.

Further, in the data stream switching device according to the present invention, the first decoding delay time for decoding the data sequence of the first data stream is the second decoding delay time.
When the output is switched from the second data stream to the first, the first decoding delay time and the second decoding delay time are longer when compared with the second decoding delay time for decoding the data stream of the data stream. A configuration may be adopted in which dummy data for compensating for a difference from the second decoding delay time is output.

If the first decoding delay time is longer than the second decoding delay time, when switching the data stream, data to be reproduced during the difference time is lost. Here, by outputting the dummy data, loss of data to be reproduced can be prevented.

Here, in the data stream switching device of the present invention, the first data stream and the second
Is a data stream compressed by the MPEG system, and the dummy data may be output in units of pictures.

In order to solve the above problem, a data stream switching method according to the present invention is to input two data streams in which a plurality of data strings are arranged, switch between the two data streams, and output one of them. A data stream switching method for storing a first data stream for each data stream, wherein when switching output from a second data stream to the first data stream, the second data stream is stored. Outputting the input first data stream following output of the data stream of the first data stream stored in the storing step after stopping the output of the stream in units of data streams. It is characterized by.

When the output of the data stream is switched, the output of the second data stream before the switching is stopped in units of a data string, so that the second data stream is switched to the data string as usual (the switching is not performed). Output reproduction is performed (as in the case). Further, the first data stream is stored for each data stream, and after the output of the second data stream is stopped, the stored data stream of the first data stream is first output, and subsequently, the input By outputting the obtained first data stream, the first data stream is output from the beginning of a certain data sequence following the output of the second data stream. Therefore, no information is lost in the data string,
The first data stream after the switching is also performed after the data sequence,
Output reproduction is performed as usual.

Here, in the data stream switching method of the present invention, the first data stream and the second
Are data streams compressed by the MPEG system, and the data sequence may be a sequence including a sequence header as a header portion and a GOP as a data portion.

Further, in the data stream switching method of the present invention, the first data stream is converted from the second data stream.
When the output is switched to the data stream of the first data stream, the first time information associated with each data string of the first data stream and the second time information associated with each data string of the second data stream May be configured to compensate for the difference.

By compensating for the difference between the first time information and the second time information, even if the first time information and the second time information are different, the first data after the switching is changed. It is possible to output and reproduce the stream continuously to the second data stream before switching.

Here, in the data stream switching method of the present invention, the first data stream and the second
Are the data streams compressed by the MPEG system, and the first time information and the second time information are time reference values, respectively.
When switching the output from the second data stream to the first data stream, a difference between the first time information and the second time information may be added to the first time information.

In the data stream switching method according to the present invention, the first decoding delay time for decoding the data string of the first data stream is equal to the delay time for decoding the data string of the second data stream. If the second decoding delay time is shorter than the second decoding delay time,
When switching the output from the data stream to the first data stream, the output of the first data stream may be delayed by a difference between the second decoding delay time and the first decoding delay time. Good.

[0024] By delaying the output of the first data stream by the difference between the second decoding delay time and the first decoding delay time, the output of the first data stream can be reduced when the first decoding delay time is shorter than the second decoding delay time. Even if there is, the decoding time of the data string of the second data stream output last can be secured. Therefore, the data stream of the second data stream is output and reproduced as usual.

In the data stream switching method of the present invention, the first decoding delay time for decoding the data stream of the first data stream is the second decoding delay time.
If the output is switched from the second data stream to the first data stream, the first decoding delay is longer than the second decoding delay time for decoding the data stream of the data stream of the first stream. A configuration may be adopted in which dummy data for compensating for the difference between the time and the second decoding delay time is output.

If the first decoding delay time is longer than the second decoding delay time, when the data stream is switched, data to be reproduced during the difference time is lost. Here, by outputting the dummy data, loss of data to be reproduced can be prevented.

Here, in the data stream switching method of the present invention, the first data stream and the second
Is a data stream compressed by the MPEG system, and the dummy data may be output in units of pictures.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A data stream switching device according to an embodiment of the present invention will be described with reference to the drawings.
The data stream switching device according to the present embodiment is an MPEG
This is a data stream switching device that inputs two data streams compressed according to a method, switches between these two data streams, and outputs one of them.

The data structure of a data stream (hereinafter, referred to as a video stream) compressed by the MPEG system is as shown in FIG. That is, a sequence header (SH) as a header part and a GOP as a data part
A video stream is configured by arranging a plurality of sequences (data strings) including (Group Of Pictures). 1
One GOP is composed of a plurality of (usually 15) pictures (PI
C), and one picture corresponds to image data for one frame of a moving image. When such a video stream is transmitted, as shown in FIG. 3B, a header (PE) is inserted between each picture and before the sequence header.
PES (Packetized Elementary Stre) with SH
am) The data structure is transmitted after being converted into a data structure. For simplicity, the following description is made using the data structure of the video stream shown in FIG.

First, the configuration of the data stream switching device according to the present embodiment will be described. FIG. 1 is a configuration diagram of the data stream switching device according to the present embodiment. The data stream switching device 10 according to the present embodiment includes two input buffers 12 and 14 and three changeover switches 16 and 1.
8, 20, a sequence buffer 22, a dummy picture generation unit 24, a re-stamp processing unit 26, an output buffer 28, and a control unit 30. Hereinafter, each component will be described in detail.

When the output terminals are connected to the subsequent processing unit, the two input buffers 12 and 14 transfer the data stored therein or the data input from the input terminal to the subsequent processing unit. In addition to the output, when the output terminal is not connected to the subsequent processing unit, the data input from the input terminal is sequentially stored.

The changeover switches 16 and 18 are one-input and three-output changeover switches.
Data input from the input terminal can be output from any one of the three output terminals (output terminals A, B, and C). The changeover switch 20 is a changeover switch having three inputs and one output, and switches any one of data input from three input terminals (input terminals A, B, and C) according to an instruction from the control unit 30. It can output from the output terminal.

The sequence buffer 22 (storage means)
When the output terminal is connected to the subsequent processing unit, the data stored inside or the data input from the input terminal is output to the subsequent processing unit, and the output terminal is connected to the subsequent processing unit. If they are not connected, the data input from the input terminal is sequentially stored. Here, the sequence buffer 22 can store a video stream for each sequence, and the data stored in the sequence buffer 22 is always (a part of) one sequence with the sequence header at the top. ing. Also,
When the storage of one entire sequence is completed, the sequence buffer 22 is temporarily reset by an instruction from the control unit 30, and the storage of the next sequence is started.

The dummy picture generation unit 24 includes a control unit 30
And outputs a predetermined amount of dummy data in accordance with the instruction from.
More specifically, the dummy picture generation unit 24 outputs dummy data in units of pictures. Such a picture is represented as a difference image.

The re-stamp processing unit 26 receives a program clock reference value (Program Clock Reference) in the video stream input from the input terminal in accordance with an instruction from the control unit 30.
nce. Hereinafter, it is referred to as PCR. ) Is corrected (hereinafter referred to as restamping) and output from the output terminal. Along with this, PTS (Presentation Time), which is time management information for reproduction output,
Stamp) and DTS (Decoding Ti)
me Stamp) is also re-stamped at the same time.

The output buffer 28 outputs the data input from the input terminal from the output terminal in accordance with an instruction from the control unit 30.

The connection relationship between the components is as follows. That is, the input end of the changeover switch 16 is connected to the output end of the input buffer 12, and the input end of the changeover switch 18 is connected to the output end of the input buffer 14.
The output terminals A of the changeover switches 16 and 18 are both connected to the input terminal of the sequence buffer 22, the output terminal C is both connected to the input terminal C of the changeover switch 20, and the output terminal B
Are both open.

The output terminal of the changeover switch 20 is connected to the input terminal of the re-stamp processing unit 26, the input terminal A is connected to the output terminal of the dummy picture generation unit 24, and the input terminal B is connected to the output terminal of the sequence buffer 22. . Further, the output end of the re-stamp processing unit 26 is connected to the input end of the output buffer 28.

A video stream can be externally input to the input terminals of the input buffers 12 and 14. The output end of the output buffer 28 can output a video stream to the outside.

The control unit 30 controls the switching timing of the changeover switches 16, 18 and 20, instructs the dummy picture generation unit 24 to generate a dummy picture,
6, and the output timing from the output buffer is controlled. The details will be described later.

Next, the operation of the data stream switching device according to the present embodiment will be described, and the data stream switching method according to the embodiment of the present invention will be described. FIG. 2 shows a changeover switch 1 when switching data streams using the data stream switching device 10.
6 is a diagram showing switching timings of 6, 18, and 20, and a data storage state of input buffers 12, 14, a sequence buffer 22, and an output buffer 28. FIG. Here, the first video stream (hereinafter, referred to as VS1) is input to the input terminal of the input buffer 12, the second video stream (hereinafter, VS2) is input to the input terminal of the input buffer 14, and the output terminal of the output buffer 28. Output from VS2 to VS1
The operation when switching to is described.

During the output of VS2, the changeover switches 16, 1
Output terminals A, C, and C are selected by the control unit 30 and connected to an input terminal or an output terminal. As a result, the input buffer 12
Are input to the input buffer 12 and stored in the sequence buffer 22. here,
Since the sequence buffer 22 is reset every time one entire sequence is stored in response to an instruction from the control unit 30, the data stored in the sequence buffer 22 always includes one sequence (one Department). On the other hand, the VS2 data input to the input buffer 14 reaches the output buffer 28 via the re-stamp processing unit 26, and is output at a predetermined time interval for each sequence according to an instruction from the control unit 30.

In this state, when a switching instruction for switching the output from VS2 to VS1 is input, the control unit 30
2, and the changeover switch 18 is switched to the output terminal B at the detection timing of the SH (detected by the input buffer 14). Therefore, thereafter, the data of VS2 remaining in the output buffer 28 is sequentially output, and the input data of VS2 is stored in the input buffer 14.

VS2 remaining in output buffer 28
Is completed, the control unit 30 switches the changeover switch 16 to the output terminal B and the changeover switch 20 to the output terminal A. Therefore, thereafter, the dummy picture generation unit 2
4 to a predetermined number of dummy pictures
6 to the output buffer 28.

Here, the dummy picture is inserted by
This processing is performed when the decode delay time of VS1 (the time required to decode each sequence) is longer than the decode delay time of VS2. That is, when the decoding delay time of VS1 is longer than the decoding delay time of VS2, when switching from VS2 to VS1, a picture to be reproduced at the difference time is generated. Therefore, by outputting the dummy picture, loss of the reproduced picture is prevented. The number of inserted dummy pictures is VS
It is determined by the control unit 30 based on the difference time between the decode delay time of No. 1 and the decode delay time of VS2. Here, a null image (an image whose pixel values are all 0) as a difference image is output from the dummy picture generation unit 24, and the image to be output and reproduced is the same as the immediately preceding image (frozen state). . On the other hand, if the decode delay time of VS1 is longer than the decode delay time of VS2, no dummy picture is inserted.

Since the changeover switch 16 is switched to the output terminal B, the data of VS1 is stored in the input buffer 12 thereafter. At that time, the data of VS1 stored in the input buffer 12 is continuous with the data of VS1 stored in the sequence buffer 22.

All the dummy pictures are output buffer 28
Is output to the control unit 30, the changeover switch 20
Is switched to the input terminal B, and the data of VS1 stored in the sequence buffer 22 is sequentially output to the re-stamp processing unit 26 from the sequence header. Here, since the PCR, PTS, and DTS of VS1 and VS2 are generally different, the PCR, PTS, and DTS of VS1, which is the switched video stream, are
The TS is re-stamped. More specifically, the control unit 30
Monitors the PCR of VS1 and the PCR of VS2, and calculates the difference between the PCR of VS1 and the PCR of VS2 as VS1.
To the VS1 as a new PCR. Along with this, the PTS and DTS are also re-stamped. As described above, VS1 PCR, PT
By re-stamping S and DTS, PCR of VS1
Even if the PCR of the VS2 is different from the PCR of the VS2, it is possible to continuously output and reproduce the VS1 after the switching to the VS2 before the switching. The VS1 re-stamped by the re-stamp processing unit 26 is output to the output buffer 28.

When the output of the VS1 data stored in the sequence buffer 22 is completed, the control unit 30 switches the changeover switches 16, 18, and 20 to the output terminal C, the output terminal A, and the input terminal C, respectively. Therefore, thereafter, the data of VS1 stored in the input buffer 12 is output to the output buffer 28 via the re-stamp processing unit 26, and the data of VS2 stored in the input buffer 14 is stored in the sequence buffer for each sequence. 22. Here, the data of VS1 stored in the input buffer 12 is stored in the sequence buffer 22.
Because it is continuous with the VS1 data stored in
In the output buffer 28, VS1 is continuous data starting from a certain sequence header. As a result, V
S2 is output and reproduced as usual (as in the case where switching is not performed) until the switching sequence, and VS1 is
After the sequence stored in the sequence buffer 22 at the time of the switching instruction, output and reproduction are performed as usual.

The VS1 or VS2 stored in the output buffer 28 is output at predetermined time intervals in sequence units in accordance with an instruction from the control unit 30. But VS
If the decoding delay time of the VS2 is shorter than the decoding delay time of the VS2, the time for decoding the last sequence of the VS2 is not secured. Therefore, the control unit 30
Delays the output of VS1 by the difference between the decoding delay time of VS1 and the decoding delay time of VS2 when the decoding delay time of VS1 is shorter than the decoding delay time of VS2. By performing such processing, even when the decoding delay time of VS1 is shorter than the decoding delay time of VS2, it is possible to secure a time for decoding the last sequence of VS2,
Output reproduction is performed as usual until the last sequence of 2.

Next, the effects of the data stream switching device according to this embodiment will be described. The data stream switching device 10 according to the present embodiment
When the output is switched to 1, VS2 is stopped in sequence units, and VS1 is sequentially output from the sequence header. Therefore, no data is lost in the sequence in both the VS2 before the switching and the VS1 after the switching, and the VS2 is output and reproduced as usual from the last sequence before the switching and the VS1 from the first sequence after the switching. You. As a result, it is possible to reduce noise generated when switching the output from VS2 to VS1.

In the data stream switching apparatus 10 according to the present embodiment, the difference between the PCR of VS1 and the PCR of VS2 added to the PCR of VS1 is re-stamped to VS1 as a new PCR.
Even if the CR and the PCR of the VS2 are different, it is possible to continuously output and reproduce the VS1 after the switching to the VS2 before the switching. Therefore, the PCR of VS1 and the P of VS2
Even if CR is different, the output is changed from VS2 to VS
It is possible to reduce noise generated when switching to 1.

In the data stream switching device 10 according to the present embodiment, when the decode delay time of VS1 is shorter than the decode delay time of VS2,
The output of VS1 is delayed by the difference between the decode delay time of S1 and the decode delay time of VS2. Therefore, even if the decode delay time of VS1 is shorter than the decode delay time of VS2, output and reproduction are performed as usual until the last sequence of VS2 at the time of switching. As a result, even when the decode delay time of VS1 is shorter than the decode delay time of VS2, it is possible to reduce noise generated when switching the output from VS2 to VS1.

In the data stream switching device 10 according to the present embodiment, when the decoding delay time of the VS1 is longer than the decoding delay time of the VS2, a dummy picture is inserted. Is prevented. As a result, even when the decoding delay time of VS1 is longer than the decoding delay time of VS2, it is possible to reduce noise generated when switching the output from VS2 to VS1.

[0054]

According to the data stream switching device or the data stream switching method of the present invention, when switching the output of the data stream, the output of the second data stream before switching is stopped in units of data strings, and the output of the second data stream after switching is switched. One data stream can be output from the beginning of the data sequence. As a result, it is possible to reduce noise generated when switching the output from the second data stream to the first data stream.

Further, in the data stream switching device or the data stream switching method of the present invention, the difference between the first time information and the second time information is compensated, so that the first time information and the second time information are compensated. Even if the information is different, the first data stream after switching can be output and reproduced continuously from the second data stream before switching. Therefore, even when the first time information is different from the second time information, the first data is not transmitted from the second data stream.
It is possible to reduce the noise generated when switching the output to the data stream of.

Further, in the data stream switching device or the data stream switching method of the present invention, at the time of switching, the output of the first data stream is delayed by the difference between the second decoding delay time and the first decoding delay time. The decoding time of the data stream of the second data stream that is output last is secured, and the second data stream is output from the data stream as usual. As a result, even when the first decoding delay time is shorter than the second decoding delay time, it is possible to reduce noise generated when switching the output from the second data stream to the first data stream. Becomes

Further, in the data stream switching device or the data stream switching method of the present invention, at the time of switching, dummy data of an amount corresponding to the difference between the first decoding delay time and the second decoding delay time is output. This prevents loss of data to be reproduced. as a result,
As a result, even when the decoding delay time of the first data stream is longer than the decoding delay time of the second data stream, when the output is switched from the second data stream to the first data stream. The generated noise can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a data stream switching device.

FIG. 2 is a diagram illustrating switching timing of each changeover switch and a data storage state of each buffer.

FIG. 3 is a diagram showing a data structure of a video stream and the like.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Data stream switching device, 12, 14 ... Input buffer, 16, 18, 20 ... Changeover switch, 22 ... Sequence buffer, 24 ... Dummy picture generation part, 26 ...
Restamping unit, 28 output buffer, 30 control unit

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[Procedure amendment]

[Submission date] January 31, 2000 (200.1.3
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006]

In order to solve the above problems, a data stream switching device according to the present invention inputs two data streams in which a plurality of data strings are arranged, and switches between the two data streams. A data stream switching device for outputting either one of the data streams, comprising a storage means for storing the first data stream for each data sequence, when switching the output from the second data stream to the first data stream. After stopping the output of the second data stream in units of a data stream, following the output of the data stream of the first data stream stored in the storage unit, the input of the first data stream is stopped. When outputting a data stream and switching the output from the second data stream to the first data stream,
A difference between first time information associated with each of the data strings of the first data stream and second time information associated with each of the data strings of the second data stream is compensated for. .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

When the output of the data stream is switched, the output of the second data stream before switching is stopped in units of a data string, so that the second data stream is switched to the data string as usual (the switching is not performed). Output reproduction is performed (as in the case). Further, the first data stream is stored for each data stream, and after the output of the second data stream is stopped, the stored data stream of the first data stream is first output, and subsequently, the input By outputting the obtained first data stream, the first data stream is output from the beginning of a certain data sequence following the output of the second data stream. Therefore, no information is lost in the data string,
The first data stream after the switching is also performed after the data sequence,
Output reproduction is performed as usual. Also, the first time information and the second
By compensating the difference between the first time information and the second time information, even if the first time information and the second time information are different, the first data stream after the switching is replaced with the second data stream before the switching. Output reproduction can be continuously performed.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Deleted

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Deleted

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

In order to solve the above problem, a data stream switching method according to the present invention is to input two data streams in which a plurality of data strings are arranged, switch between the two data streams, and output one of them. A data stream switching method for storing a first data stream for each data stream, wherein when switching output from a second data stream to the first data stream, the second data stream is stored. After stopping the output of the stream in units of the data stream, outputting the input first data stream following the output of the data stream of the first data stream stored in the storing step, From the second data stream to the first
When the output is switched to the data stream of the first data stream, the first time information associated with each data string of the first data stream and the second time information associated with each data string of the second data stream The difference is compensated for.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

When the output of the data stream is switched, the output of the second data stream before the switching is stopped in units of a data string, so that the second data stream is switched to the data string as usual (the switching is not performed). Output reproduction is performed (as in the case). Further, the first data stream is stored for each data stream, and after the output of the second data stream is stopped, the stored data stream of the first data stream is first output, and subsequently, the input By outputting the obtained first data stream, the first data stream is output from the beginning of a certain data sequence following the output of the second data stream. Therefore, no information is lost in the data string,
The first data stream after the switching is also performed after the data sequence,
Output reproduction is performed as usual. Also, the first time information and the second
By compensating the difference between the first time information and the second time information, even if the first time information and the second time information are different, the first data stream after the switching is replaced with the second data stream before the switching. Output reproduction can be continuously performed.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Deleted

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Deleted

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0045

[Correction method] Change

[Correction contents]

Here, the dummy picture is inserted by
This processing is performed when the decode delay time of VS1 (the time required to decode each sequence) is longer than the decode delay time of VS2. That is, when the decoding delay time of VS1 is longer than the decoding delay time of VS2, when switching from VS2 to VS1, a picture to be reproduced at the difference time is generated. Therefore, by outputting the dummy picture, loss of the reproduced picture is prevented. The number of inserted dummy pictures is VS
It is determined by the control unit 30 based on the difference time between the decode delay time of No. 1 and the decode delay time of VS2. Here, a null image (an image whose pixel values are all 0) as a difference image is output from the dummy picture generation unit 24, and the image to be output and reproduced is the same as the immediately preceding image (frozen state). . On the other hand, if the decode delay time of VS1 is shorter than the decode delay time of VS2, no dummy picture is inserted.

Continued on the front page F-term (reference) 5C059 MA00 RB02 RB09 RB14 RC04 RC07 RC24 RE01 TA01 TA57 TA72 TA80 TB03 TB04 TC00 TD05 UA05 UA37 5K014 AA05 CA02 EA01 FA01 5K030 GA11 KA01 KA03 KX11 MB06 MD02 5K047 A0413A04 JJ12 KK56

Claims (14)

[Claims] 1. A data stream switching device for inputting two data streams in which a plurality of data streams are arranged, switching between the two data streams, and outputting one of the data streams. A storage unit for storing the output of the second data stream when the output is switched from the second data stream to the first data stream. A data stream switching device that outputs the input first data stream following output of a data sequence of the first data stream stored in the first data stream. 2. The first data stream and the second data stream.
The data streams are data streams compressed by the MPEG system, respectively, and the data sequence is a sequence including a sequence header as a header part and a GOP as a data part. 2. The data stream switching device according to claim 1. 3. When switching output from the second data stream to the first data stream, the first data stream
And compensating for a difference between the first time information associated with each of the data streams of the data stream and the second time information associated with each of the data streams of the second data stream. Or the data stream switching device according to 2. 4. The first data stream and the second data stream.
Are the data streams compressed by the MPEG method, respectively, the first time information and the second time information are time reference values, respectively. 4. The data stream according to claim 3, wherein when switching the output to the first data stream, a difference between the first time information and the second time information is added to the first time information. Switching device. 5. A first decoding delay time for decoding a data string of the first data stream is compared with a second decoding delay time for decoding a data string of the second data stream. When the output is switched from the second data stream to the first data stream, the output of the first data stream is changed to the second decoding delay time and the first decoding delay time. The data stream switching device according to any one of claims 1 to 4, wherein the data stream switching device is delayed by the difference of 6. A first decoding delay time for decoding a data string of the first data stream, compared with a second decoding delay time for decoding a data string of the second data stream. If long, the second
When switching the output from the data stream to the first data stream, dummy data for compensating for a difference between the first decoding delay time and the second decoding delay time is output. The data stream switching device according to claim 1. 7. The first data stream and the second data stream.
7. The data stream switching device according to claim 6, wherein each of the data streams is a data stream compressed by the MPEG system, and outputs the dummy data in units of pictures. 8. A data stream switching method for inputting two data streams in which a plurality of data streams are arranged, switching between the two data streams, and outputting one of the two data streams, comprising: And when the output is switched from the second data stream to the first data stream, the output of the second data stream is stopped on a data string basis, and then the storage step is performed. Outputting the input first data stream after outputting the data stream of the first data stream stored in the data stream switching method. 9. The method of claim 1, wherein the first data stream and the second data stream
9. The data stream of claim 1, wherein each of the data streams is a data stream compressed by the MPEG system, and the data sequence is a sequence including a sequence header as a header part and a GOP as a data part. 2. The data stream switching method according to item 1. 10. When the output is switched from the second data stream to the first data stream, first time information and the second data associated with each of the data strings of the first data stream are provided. The data stream switching method according to claim 8 or 9, wherein a difference from the second time information associated with each of the data strings of the stream is compensated. 11. The first data stream and the second data stream are each a data stream compressed by the MPEG system, and the first time information and the second time information are respectively A time reference value, wherein when switching output from the second data stream to the first data stream, the difference between the first time information and the second time information is converted to the first time information. The data stream switching method according to claim 10, further comprising: 12. A first decoding delay time for decoding a data string of the first data stream is compared with a second decoding delay time for decoding a data string of the second data stream. When the output is switched from the second data stream to the first data stream, the output of the first data stream is changed to the second decoding delay time and the first decoding delay time. The data stream switching method according to any one of claims 8 to 11, wherein the data stream is delayed by the difference of 13. A first decoding delay time for decoding a data string of the first data stream is compared with a second decoding delay time for decoding a data string of the second data stream. When the output is switched from the second data stream to the first data stream, dummy data for compensating for the difference between the first decoding delay time and the second decoding delay time is output when the output is switched from the second data stream to the first data stream. 8. The method according to claim 8, wherein
3. The data stream switching method according to any one of 2. 14. The data stream according to claim 1, wherein each of the first data stream and the second data stream is a data stream compressed by an MPEG system, and the dummy data is output in units of pictures. 14. The data stream switching method according to claim 13.