JPH1175156A - Stream editer and stream decoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the stream editer that edits a moving image data stream so as to be reproduced without disturbing a video image. SOLUTION: In the case of editing a stream with a structure of a group of picture GOP by the editer 2, an edit reception means 3 receives an input command of edit class with respect to the stream 1. Furthermore, edit processing means 4-6 apply edit processing to the stream, based on the edit class, and a header information read means 7 reads independent information of a GOP directly from header information of the GOP just after the GOP arranged just before is changed attended with the edit processing Then a header information update means 8 receives an instruction input of pattern selection information with respect to the just-after GOP when the just-after GOP is not independent, and adds the pattern selection information instructed to the header information of the just-after GOP to update the header information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stream editing apparatus and a moving picture data decoding apparatus, and more particularly to a stream editing apparatus and a group editing apparatus for editing a stream having a group of pictures (hereinafter sometimes referred to as GOP) structure. The present invention relates to a stream decoding device that decodes a stream having an of-picture structure.

[0002]

2. Description of the Related Art At present, as an encoding method for compressing data of a color moving image, a moving picture coding expert (MPEG) for a storage medium such as a CD-ROM is used.
oup) 1 and communication media by extending MPEG1;
MPEG2 has been standardized so that it can be commonly used for broadcasting and communication.

In MPEG1, when a frame cut out from moving image data is compressed, a specified I picture,
Encoding is performed with an arbitrary image type among the three image types of a P picture and a B picture to increase the compression efficiency.

[0004] Among them, in the case of an I picture, the entire screen is intra-coded (intra-frame coding). For P pictures, inter-frame forward prediction coding is performed based on the I picture or P picture that has appeared earlier. Then, in the B picture, bidirectional predictive encoding is performed based on the I picture or P picture that appears first and the I picture or P picture that appears later.

[0005] When all of a series of moving images depend on each other, only simple reproduction is possible. That is, trick modes such as fast forward, rewind, halfway play, and reverse play cannot be supported. So M
In PEG1, a prescribed number of pieces of picture data including at least one I picture are collectively referred to as a group of pictures. Then, trick mode reproduction is performed using this GOP as a unit. Each GOP is added with header information indicating the property of the GOP. At the decoder, this header information allows random access for trick mode.

The header information includes a GOP start code,
A time code indicating the time from the head of the stream of the GOP is included. Also included are a closed GOP flag indicating whether the GOP is independent and a broken link flag indicating whether data of the immediately preceding GOP can be used in reproducing the GOP.

When a closed GOP flag is set in the header information of a GOP included in a generated stream, the GOP is independent. This is because the GOP
This indicates that there is no picture data (B picture) encoded based on the prediction from the picture data included in another GOP. Accordingly, the stream emphasizes independence rather than image quality, and has high editability.

When GOPs that are not independent are cut out by editing and are connected, a broken link flag is set in the header information. In such a case, for the B picture that is not independent, its GO
Decoding is performed only by backward prediction from I and P pictures in P.

[0009]

However, if there is a GOP in which the data of the immediately preceding GOP cannot be used for reproduction in spite of the fact that the GOP is not independent, the video is distorted due to the B picture included in the GOP. There was a problem that it might be.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a stream editing apparatus capable of editing a stream of moving image data so that the stream can be reproduced without disturbing the video.

Another object of the present invention is to provide a
An object of the present invention is to provide a stream decoding device capable of reproducing a stream of encoded moving image data without disturbing video even when a link flag is set.

[0012]

According to the present invention, in order to solve the above-mentioned problems, in a stream editing apparatus for editing a stream having a group-of-picture structure, edit accepting means for accepting an input instruction of an edit type for the stream. Editing processing means for performing editing processing on the stream based on the editing type; and header information of a group of picture immediately after a change occurs in a group of pictures arranged immediately before the editing processing. A header information reading means for reading the independence information of the immediately following group of pictures, and, if the immediately following group of pictures is not independent, the header information reading means of the picture selection information for the immediately following group of pictures. Accepts an instruction input and adds the header information of the immediately following group of pictures. Stream editing device is provided, characterized in that it comprises a header information updating means for updating the header information by adding Kigagara selection information.

When editing a stream having a group-of-picture structure with such a stream editing apparatus, the edit accepting means accepts an edit type input instruction for the stream. The editing processing means performs an editing process on the stream based on the editing type.
The header information reading means reads the independence information of the immediately succeeding group of pictures from the header information of the immediately following group of pictures in which the group of pictures arranged immediately before the editing process is changed. Then, if the immediately following group of pictures is not independent, the header information updating means determines that the immediately following group of pictures
Accepts an instruction input of picture selection information for a picture,
Immediately after, the pattern selection information instructed and input is added to the header information of the group of pictures to update the header information.

As described above, in the stream editing apparatus of the present invention, when a group of picture immediately before a group of pictures that is not independent is changed by editing, it is included in the group of pictures immediately after. Since the pattern selection information designating the alternative expression for the non-independent picture data (B picture) thus added is immediately added to the header information of the GOP, the moving picture stream is edited so that it can be reproduced without disturbing the video. It becomes possible.

According to another aspect of the present invention, there is provided a stream decoding apparatus for decoding a stream having a group of pictures structure, wherein the stream separating unit extracts the group of pictures by separating the stream. Header information reading means for reading independence information, dependency information and picture selection information of the group of pictures from the header information of the group of pictures, and the group of pictures is -If it cannot depend on the picture of picture and has picture selection information, the group of picture is
A stream decoding device comprising: a moving image decoding means for decoding based on the pattern selection information.

When a stream having a group of picture structure is decoded by such a stream decoding device, the stream separating means separates the stream and extracts a group of picture. The header information reading means reads independence information, dependency information, and picture selection information of the group of pictures from the header information of the group of pictures. If the group of pictures is independent and cannot depend on other groups of pictures and has picture selection information, the video decoding means Is decoded based on the picture selection information.

As described above, in the stream decoding apparatus of the present invention, when decoding a stream of encoded moving image data, the group of pictures of the stream are not independent of each other. Even when it is not possible to depend on the immediately preceding group of pictures (the broken link flag is set), since the group of pictures is decoded based on the picture selection information extracted from the header information, the video is decoded. It is possible to reproduce without disturbing.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the principle configuration of the stream editing device of the present invention.

The stream editing apparatus 2 of the present invention provides a stream 1 having a group of pictures (GOP) structure.
In order to edit the file, there are editing accepting means 3, GOP deleting means 4, GOP inserting means 5, stream switching means 6, header information reading means 7, and header information updating means 8.

Here, the edit accepting means 3 accepts an edit type input instruction for the stream 1. If the received editing type is deletion, the operation command is sent to the GOP deletion means 4, if it is inserted, to the GOP insertion means 5, and if it is switching, the operation command is sent to the stream switching means 6. Output.

The GOP deletion means 4 performs a deletion process when an operation command is received from the edit reception means 3 and a designation of a GOP range to be deleted in the stream 1 is received from the user. That is, the GOP included in the stream 1 in the range of the GOP to be deleted is deleted. Then, the GOP placed immediately after the deletion applicable GOP range in the stream 1 is notified to the header information reading unit 7 as the immediately following GOP.

The GOP insertion means 5 performs an insertion process on the stream 1 upon receiving an operation command from the edit reception means 3 from the user to specify an insertion position in the stream 1 and to input an insertion GOP. That is, the stream 1 is cut at the received insertion position, and the received insertion GO
Insert P. Then, the header information reading unit 7 is notified of the GOP placed immediately after the insertion position in the stream 1 and the GOP at the head of the insertion GOP as the immediately following GOP.

When the stream switching means 6 receives an operation command from the editing receiving means 3 and receives a designation of a switching position in the stream 1 and an input of the switching stream from the user, it performs a switching process on the stream 1. That is, stream 1 is cut off at the accepted switching position,
Connect the received switching stream. Then, the header information reading unit 7 is notified of the GOP located at the head of the switching stream as the immediately following GOP.

The header information reading means 7 reads, from the header information of the GOP immediately after the notification, the independence information of the GOP immediately thereafter. If the GOPs are not independent immediately, the header information updating means 8 is notified of this. Here, the independence information read by the header information reading means 7 is whether or not the GOP has non-independent picture data (B picture) encoded depending on picture data included in another GOP. Is a flag indicating

When the header information updating means 8 is notified by the header information reading means 7 that the GOP is not independent and receives an input of design selection information from the user, the pattern information is added to the header information of the GOP immediately after. The header information is updated by adding information. The pattern selection information is immediately after GO
A black image instruction or the like for instructing an alternative expression for the non-independent picture data (B picture) included in P, wherein the user instructs to display a black image instead of the non-independent picture data (B picture). Can be selected.

Since the header information can include the dependency information of the GOP, the header information updating means 8 also updates the dependency information indicating that the GOP does not depend on another GOP at the time of this update. Record in this header information.

As described above, in the stream editing apparatus 2 of the present invention, when the GOP immediately before the GOP that is not independent is changed by editing, the non-independent picture data (B picture) included in the immediately following GOP is changed. Immediately after this, the pattern selection information indicating the alternative expression is added to the header information of the GOP, so that the moving image stream can be edited so as to be reproduced without disturbing the video.

Here, a procedure when the stream editing apparatus 2 edits the stream 1 of the moving image data will be described. FIG. 2 is a flowchart showing a procedure for editing the stream 1 of the moving image data by the stream editing apparatus 2 shown in FIG. Hereinafter, description will be given along the step numbers. [S1] The edit accepting means 3 accepts an edit type input by a user. [S2] The content of the accepted editing type is determined. If the edit type is "delete", the edit accepting means 3 issues an operation command to the GOP deleting means 4, and proceeds to step S3. If the editing type is "insertion", the editing accepting means 3 issues an operation command to the GOP inserting means 5, and proceeds to step S5. If the editing type is "switching", the editing accepting unit 3 issues an operation command to the stream switching unit 6, and proceeds to step S8. [S3] The GOP deletion unit 4 receives a deletion application GOP range in the stream 1 input from the user. [S4] The GOP deletion means 4 receives the received deletion application GO.
The GOP in the P range is deleted. Then, GO 1 placed immediately after the deletion application GOP range in stream 1
P is set to “immediately after GOP” and is notified to the header information reading unit 7. [S5] The GOP insertion means 5 receives designation of an insertion position in the stream 1 input from the user. [S6] The GOP insertion means 5 receives an insertion GOP input from the user. [S7] The GOP insertion means 5 cuts the stream 1 at the insertion position received in step S5, and inserts the insertion GOP received in step S6. Then, the GOP placed immediately after the insertion position in stream 1
And the first GOP of the insertion GOP as the “immediately after GOP” to the header information reading unit 7. [S8] The stream switching unit 6 accepts a designation of a switching position in the stream 1 input from the user. [S9] The stream switching unit 6 receives a switching stream input from the user. [S10] The stream switching means 6 disconnects the stream 1 at the switching position received in step S8, and connects the switching stream received in step S9. Then, GO at the beginning of the switching stream
P is notified to the header information reading means 7 as “immediately after GOP”. [S11] The header information reading means 7 reads, from the header information of the GOP immediately after the notification, the independence information of the GOP immediately thereafter. [S12] The header information reading means 7 determines whether or not the immediately following GOP is independent from the read independence information. If the GOPs are immediately independent, the processing of this flowchart ends. If the immediately following GOPs are not independent, the GOP is notified to the header information updating means 8, and the process proceeds to step S13. [S13] The header information updating means 8 receives an instruction input of the pattern selection information from the user. [S14] The header information updating means 8 updates the header information by adding the pattern selection information received in step S13 to the header information of the immediately following GOP. Since the header information can include the dependency information of the GOP, the header information updating means 8 also includes, at the time of this update, the dependency information indicating that the immediately following GOP does not depend on another GOP. To record.

As described above, in the stream editing apparatus 2 of the present invention, when the GOP immediately before the GOP which is not independent is changed by editing, the non-independent picture data (B picture) included in the immediately following GOP is changed. Immediately after this, the pattern selection information indicating the alternative expression is added to the header information of the GOP, so that the moving image stream can be edited so as to be reproduced without disturbing the video.

Here, a stream having a GOP structure to be edited by the stream editing apparatus of the present invention will be described. FIG. 3 is a diagram illustrating a manner in which the order of arrangement of pictures changes when a stream having a GOP structure is generated by encoding a moving image and when a stream is decoded to obtain a reproduced image.

When encoding a frame cut out from a series of moving images 10 to generate a stream 20, a B picture using bidirectional prediction is encoded after the dependent I picture or P picture is encoded and arranged. , Encoding and placement. When the stream 20 is decoded and the playback image 30 is played, the order of the frames is replaced so as to be the same as that of the moving image 10. Here, in order to explain the flow, a frame that is coded to be an I picture is shown as an I picture through a moving image 10 to a reproduced image 30.
A frame that is coded to be a P picture is also shown as a P picture through the moving images 10 to 30, and a frame that is similarly coded to be a B picture is also a moving image 10.
-Shown as a B picture through the reproduced picture 30. further,
The moving image 10 shown here is a series of images that have not been edited at all, and includes GOP _n-1 and GOP _n , GOP _{n + 1}
Is a continuous moving image.

When the stream 10 is generated by encoding the moving picture 10, the P picture is encoded depending on the I picture that has appeared before. The B picture is coded depending on both the immediately preceding I and P pictures and the immediately succeeding I and P pictures. For example, the frame 1 shown in FIG.
2 is generated depending on the P picture 11 and the P picture 13. Therefore, the frame 12 is arranged as a B picture after the P picture 11 and the P picture 13 are arranged.

The frame 14 is coded depending on the P picture 13 and the I picture 15. Therefore, the frame 14 is arranged as a B picture after the P picture 13 and the I picture 15 are arranged.

As described above, the order of the pictures arranged in the stream 20 is different from that of the moving picture 10 before encoding. Therefore, when decoding the stream 20 and reproducing the reproduced image 30, the reproduction is performed while the order is restored. Note that in FIG. 3, the frames 11, 1
2, 13, 14, and 15 are frames 31 of the playback image 30,
32, 33, 34, and 35.

Here, a stream switching device to which the stream editing device of the present invention is applied will be described. FIG.
FIG. 1 is a diagram showing a detailed configuration of a stream switching device to which a stream editing device of the present invention is applied.

The stream switching device 40 to which the stream editing device of the present invention is applied switches between the stream A and the stream B according to a switching control signal, and generates a stream C. Here, the stream switching device 40
P header information reading units 41 and 42, a timing information generation unit 43, timing adjustment memories 44 and 45,
A GOP header information generator 46, a black screen generator 47,
It has GOP header information rewriting sections 48 and 49 and multiplexed stream generation means 50.

GOP header information reading units 41 and 42
Is based on the header information of the GOPs of the streams A and B.
The number of pictures N of P and the independence information of GOP are read.
The number N of read pictures is notified to the timing information generation unit 43. The read independence information is notified to the GOP header information generation unit 46.

The timing information generator 43 receives a switching control signal for instructing switching of streams. Further, the timing information generation unit 43 transmits each G to be notified.
From the number of pictures N of the OP, the stream A and the stream B
The time relationship with is always calculated. Then, from the time relationship between the two streams being calculated and the switching control signal,
Generate timing information for switching.

The timing adjustment memories 44 and 45 perform time adjustment for switching and rewriting of GOP header information. The GOP header information generation unit 46 receives image selection information from a user or the like. The GOP header information generator 46 includes a timing information input from the timing information generator 43 and a GOP header information reader 41.
It is determined whether or not the header information needs to be rewritten based on the independence information input from. If rewriting is necessary, new header information is generated based on the pattern selection information.

Here, the header information will be described. MP
In the case of EG, the header information of the GOP is GSC (Group St.
art Code: GOP start code) and TC (Time Code)
: Time code), CG (Closed GOP: Independence information indicating that an image in a GOP can be reproduced independently of another GOP), and BL (Broken Link: Previous GO)
Dependency information indicating that the P data cannot be used for editing). Also, GOP header information includes
ESC (Extension Start Code: extension data start code for the future) and GED (Group Extension Data: extension data), UDSC (User Data Start Code: user data start code) and UD (User Data: user data)
Can be included.

The GOP header information generator 46 of the stream switching device 40 to which the stream editing device of the present invention is applied.
In the case where the switching of streams causes a GOP that cannot be used in decoding the preceding GOP data (BL = 1) despite being independent (CG = 0), the GOP of this GOP New header information is generated by adding the pattern selection information to the UD area of the header information.

When a black image generation instruction is given from the GOP header information generation unit 46, the black image generation unit 47 generates a black image which is a still image in which the entire screen is filled with black, and multiplexes the black image. It is input to the stream generation unit 50. The GOP header information rewriting units 48 and 49 rewrite the header information of the corresponding GOP with new header information that is input when the GOP header information generation unit 46 instructs to rewrite the header information of a specific GOP.

The multiplexed stream generator 50 switches the black image, the stream A and the stream B based on the timing information input from the timing information generator 43, and generates a stream C.

As described above, in the stream switching device 40 to which the stream editing device of the present invention is applied, a GOP which is not independent but cannot be used for decoding preceding GOP data is generated due to the switching process. In this case, picture selection information indicating an alternative expression for the non-independent picture data (B picture) included in the GOP is added to the header information of the GOP, so that the moving image stream can be transmitted without disturbing the video. It is possible to generate a new stream by switching to be able to reproduce.

A stream decoding apparatus for decoding a stream edited by the stream editing apparatus of the present invention to obtain a reproduced image is provided by a header information reading means for reading, from header information of a GOP, dependency information and picture selection information of the GOP. If the GOP is not independent (CG = 0) but cannot depend on another GOP (BL = 1) and has pattern selection information, the GOP is read Moving image decoding means for decoding based on the pattern selection information.

FIG. 5 shows how the arrangement order of pictures changes when a stream generated by the stream switching device 40 to which the stream editing device of the present invention is applied is decoded to obtain a reproduced image. FIG.

Here, the stream 50 is obtained by connecting two types of streams at the switching position 50a.
Since there is no relationship between P _x and GOP _n , frame 6
When decoding 2, the P picture corresponding to the frame 61 cannot be used.

In the present invention, since the pattern selection information is added to the header information of GOP _n , if the added pattern selection information is a black image instruction at the time of decoding, it is a B picture. As a substitute expression of the frame 62, a black image is displayed to obtain a reproduced image 60.

When the added picture selection information is a freeze instruction, the reproduced picture 60 is obtained by displaying the frame 61 again as an alternative expression of the frame 62 which is a B picture.

Further, when the added picture selection information is an incomplete instruction, the picture selection information bidirectionally depends on the I and P pictures and the I picture 63 that should have been included in GOP _n-1. As an alternative expression of the frame 62, which was a B-picture, an incomplete expression that depends only on the I-picture 63 in the reverse direction is generated and displayed to obtain a reproduced image 60.

If the added picture selection information is a pseudo picture instruction, a cross dissolve of a still picture from the P picture 61 and the I picture 63 is used as an alternative expression of the frame 62 which was a B picture. Is generated and displayed, and a reproduced image 60 is obtained.

As described above, although the stream editing apparatus of the present invention is not independent, a picture indicating an alternative expression for non-independent picture data (B picture) included in a GOP that cannot be dependent on another GOP. Since the selection information is added to the header information of this GOP, it is possible to edit the moving image stream so that it can be reproduced without disturbing the video.

In the stream decoding device of the present invention,
Even if the GOPs of the stream are not independent but cannot be dependent on other GOPs for decoding,
The stream of the encoded moving image data can be reproduced based on the added picture selection information without disturbing the video.

The stream containing the pattern selection information edited by the stream editing apparatus of the present invention has a function of reproducing a reproduced image based on the pattern selection information because data compatibility is maintained. There is no inconvenience when decoding is performed by a decoding device that does not have the same function.

[0055]

As described above, according to the stream editing apparatus of the present invention, when the GOP immediately before the immediately following group of pictures that is not independent is changed by editing, the non-independent Picture selection information indicating an alternative expression for picture data (B picture)
Immediately after this, the configuration is added to the header information of the GOP, so that the moving image stream can be edited so that it can be reproduced without disturbing the video.

As described above, in the stream decoding apparatus of the present invention, when decoding a stream of encoded moving image data, the stream group
Even if the picture of interest (GOP) is not independent, but cannot depend on the immediately preceding GOP for decoding (the broken link flag is set), this GOP is extracted from the header information. Since the decoding is performed based on the selection information, the video can be reproduced without disturbing the video.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the principle configuration of a stream editing device according to the present invention.

FIG. 2 is a flowchart showing a procedure for editing a stream of moving image data by the stream editing apparatus shown in FIG. 1;

FIG. 3 is a diagram illustrating a manner in which the arrangement order of pictures changes when a stream having a GOP structure is generated by encoding a moving image and when a stream is decoded to obtain a reproduced image.

FIG. 4 is a diagram showing a detailed configuration of a stream switching device to which the stream editing device of the present invention is applied.

FIG. 5 is a diagram illustrating a situation where the order of arrangement of pictures changes when a stream switching device to which the stream editing device of the present invention is applied decodes a newly generated stream to obtain a reproduced image. .

[Explanation of symbols]

1 stream 2 stream editing device 3
Edit accepting means, 4 GOP deleting means, 5 GOP inserting means, 6 Stream switching means, 7 Header information reading means, 8 Header information updating means.

Claims (9)

[Claims] 1. A stream editing apparatus for editing a stream having a group-of-picture structure, comprising: an edit receiving unit for receiving an input instruction of an edit type for the stream; and performing an edit process on the stream based on the edit type. Editing processing means for reading the independence information of the immediately following group of pictures from the header information of the immediately following group of pictures after the change of the group of pictures arranged immediately before the editing processing When the header information reading means and the immediately following group of pictures are not independent, an instruction input of picture selection information for the immediately following group of picture is received, and the immediately following group of picture is received.
A stream editing apparatus, comprising: header information updating means for updating the header information by adding the pattern selection information to the header information of the picture. 2. The editing processing means receives a designation of a switching position in the stream and an input of a switching stream, disconnects the stream at the switching position, connects the switching stream, and sets a first group of the switching stream. 2. The stream editing apparatus according to claim 1, wherein the stream editing unit is a stream switching unit that sets an of picture as a group of pictures immediately after. 3. The editing processing means receives designation of a deletion application group of picture range, which is an unnecessary portion in the stream, deletes the deletion application group of picture range, and deletes the deletion application group of picture in the stream. 2. The stream editing apparatus according to claim 1, wherein the stream editing device is a group of picture deleting unit that sets a group of picture located immediately after the group of picture range as a group of picture immediately after. 4. The editing processing means receives designation of an insertion position in the stream and input of the insertion group of pictures, cuts off the stream at the insertion position, and inserts the insertion group of pictures. And inserting a group of picture in which the group of picture positioned immediately after the insertion position in the stream and the first group of picture of the insertion group of picture are set as the immediately following group of picture. 2. The stream editing apparatus according to claim 1, wherein said stream editing apparatus is a means. 5. The independence information read by the header information reading means is a non-independent information encoded in the immediately following group of pictures depending on picture data included in another group of pictures. 2. The stream editing apparatus according to claim 1, wherein the stream editing apparatus indicates whether picture data exists. 6. The picture selection information for which the header information updating means accepts an instruction input indicates an alternative expression for non-independent picture data included in the immediately following group of pictures. Claim 1
The stream editing device as described. 7. An image processing apparatus comprising: a black image generation unit that generates a black image picture that is a still image in which the entire screen is filled with black; A black image instruction indicating a black image picture, a freeze instruction indicating picture data immediately before the non-independent picture data, and a non-independent picture data as an alternative expression of the non-independent picture data included in the non-independent picture data. An incomplete instruction indicating an incomplete expression, a first effective picture having a data amount equal to or greater than a prescribed value, which is included in a group of pictures located immediately before the immediately following group of pictures in the edit stream, and Immediately after, a pseudo picture generated from a second effective picture that is included in the group of pictures and has a data amount larger than a specified value Pseudo-picture instruction to instruct the
The stream editing device according to claim 1, wherein the stream editing device is any one of the following. 8. A stream decoding device for decoding a stream having a group of picture structure, comprising: a stream separation unit for separating the stream to extract a group of picture; and header information of the group of picture. Header information reading means for reading independence information, dependency information and pattern selection information of the group of pictures from the group of pictures, wherein the group of pictures cannot depend on another group of pictures, A stream decoding device, comprising: moving picture decoding means for decoding the group of pictures based on the picture selection information, when having the selection information. 9. The dependency information read by the header information reading means includes the group of pictures,
9. The stream decoding apparatus according to claim 8, wherein whether or not decoding is to be performed depends on the immediately preceding group of pictures.