JP2001145067A - Real time encoder and real time encoding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a real time encoder and a real time encoding method that can store line 21 data superimposed on an analog video signal as user data in the same timing as that of a received image and display proper character information from an encoded image even when a scene is changed. SOLUTION: When a GOP header is generated in the case of generating a video stream, an area to store the line 21 data is reserved, and when coding of all GOPs is finished, the line 21 data extracted from the video signal are sroted in the area reserved in the case of generating the GOP header.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a real-time encoding apparatus and a real-time encoding method recording medium for encoding a video signal in real time to create a program stream in which a video stream and other streams are multiplexed. The present invention relates to a real-time encoding device and a real-time encoding method for storing line 21 data included in a signal in a GOP header of a video stream.

[0002]

2. Description of the Related Art A video material such as a movie video is encoded in accordance with MPEG2 which is a reproduction-only disc DVD standard, and a stream in which video, audio, subtitles and the like are encoded is created, and the created streams are multiplexed. There is an encoding device that records an encoded stream on a recording medium such as an optical disk or a magneto-optical disk.

A video signal to be encoded includes N
There is a video signal of the TSC system, and a video signal of the NTSC system scans 262 and a half scanning lines twice by interlace, and draws a total of 525 lines. This 26
Of the two and a half scanning lines, Nos. 22 to 262 are used for actual video transmission, and Nos. 1 to 21 are vertical blanking periods. In the 21st of the vertical blanking period (different signal types in field 1 and field 2), for example, character information such as English subtitle information is used as line 21 data as a vertical blanking period of the video signal shown in FIG. 21st waveform data area (Charac
ter One, Character Two).

On the other hand, an MPEG2 video stream defined by ISO 13818-2 has a sequence header (Sequence Header) and a GOP header (G
OP header), an I picture (I-Picture), a B picture (B-Picture), and a P picture (P-Picture), and the line 21 data can be stored in the GOP header as user data. In the following, I
Pictures, B pictures and P pictures are GOP (Grou
p of Pictures).

The line 21 data is stored in user data as shown in FIGS.
Bit configuration user data start code (user_dat
a_start_code), 16-bit line 21 data indication data (line21_indicator), and 1-bit GOP top field flag (top_field_flag_of_)
gop), the number of fields to be displayed in a 6-bit GOP (number_of_displayed_field_gop), a 7-bit marker bit (marker_bit), a 1-bit switch of line 21 (line21_switch), and a 16-bit line 21 data (Line21_data) and a reserved area (reserved). '0000 01B2h' as user data start code
Is described, and '4343h' is described as instruction data of the line 21. In the case of the top field of the GOP, “1b” is set in the top field flag of the GOP, and in the case of the bottom field of the GOP, “0” is set in the top field flag of the GOP.
b ′ is described in ISO13818-2, and the number of fields displayed by the GOP is GOP
Indicates the number of fields to be displayed, and the same number as the line 21 data is described. Further, the marker bit describes "111 1111b", and the switch of the line 21 describes that the line 21 data is valid in the case of "1b" and the line 21 data in the case of "0b". It states that it is invalid. Line 21 data is 7-bit data and 1
Field 1 data (line21_data1) and field 2 data (line21_data
It consists of 2).

[0006] A conventional encoding device, as shown in FIG.
A video decoder unit 10, an MPEG2 video encoder unit 11, a video buffer unit 12, a line 21 data buffer unit 13, an audio ADC unit 14, an MPE
G audio encoder unit 15, audio buffer unit 16, packetizer unit 17, controller unit 18
It is composed of

The conventional encoding device having such a configuration operates as follows. The video decoder unit 10 converts an analog video signal, which is an NTSC video signal input from a video input, into a digital video signal,
A video signal digitized by the MPEG2 video encoder unit 11 is output as an MPEG2 video stream defined by ISO 13818-2, the video buffer unit 12 temporarily holds the video stream, and is prepared in the line 21 data buffer unit 13 in advance. The line data is temporarily stored, the audio ADC unit 14 converts an analog audio signal input from an audio input into a digital audio signal, and converts the audio signal digitized by the MPEG audio encoder unit 15 into ISO11172-3.
And outputs an audio stream of MPEG1 defined by the above, and temporarily holds the audio stream in the audio buffer unit 16. The packetizer 17 packs the video stream and the audio stream stored in the video buffer 12 and the audio buffer 16 as a program stream. In the controller section 18, the MPEG2 video encoder section 11, the MPE
The G audio encoder 15 and the packetizer 17 are controlled.

FIG. 10 is a flowchart showing a procedure for creating a video stream in the MPEG2 video encoder unit 11 of the conventional encoding device. First, parameters required for encoding are set in initial settings (S
1), a sequence header and a GOP header are created (S2, S3). After creating the GOP header, the controller 18 checks whether data is stored in the line 21 data buffer 13 (S4), and if there is line 21 data, creates the user data storing the line 21 data (S5). If the line 21 data does not exist, the following processing is executed without creating user data. As the line 21 data, line 21 data prepared in advance separately from the video signal is used, and as shown in FIG.
The line 21 data corresponding to the OP is stored in the GOP header located at the head of the GOP.

Next, a frame start process, a picture start process, and a slice start process for setting a code amount after forming a GOP header, setting a code amount and a quantization step size as parameters necessary for coding and creating a header for each layer, and starting a slice. Processing is performed (S6, S7, S8). Next, a macroblock process for performing actual encoding is executed (S9). The encoding of one picture is completed by repeatedly executing the processing after the slice processing (S10).

[0010] Each time encoding of one picture is completed, the end of the sequence is determined (S11). If the sequence is completed, the encoding is terminated. GO if not sequence end
It is determined whether encoding of the number of pictures constituting P has been completed,
If there are still pictures forming the GOP, the process starts from the frame start process. If the coding of all the pictures forming the GOP is completed, it is assumed that the coding of one GOP has been completed. The process is executed from the sequence header creation (S12).

FIG. 11 shows a flow of the creation procedure in the packetizer 17 for packing the video stream and the audio stream (the creation procedure is omitted) created by the flow of FIG. 10 as a program stream. Each stream encoded by the MPEG2 video encoder unit 11 and the MPEG audio encoder unit 15 shown in FIG. 9 is stored in each buffer. The packetizer 17 includes a video buffer unit 12 and an audio buffer unit 1.
The pack to be output is selected based on the buffer occupancy (the amount of data stored in the buffer) and the virtual buffer occupancy on the decoder side. First, the amount of data (2048 bytes) that can be packed is stored in the video buffer unit 12 (S2).
1) If the buffer on the decoder side outputs a pack and the buffer does not overflow (S22), the video stream of the video buffer unit 12 is output as a program stream (S23). If the video stream does not satisfy the above conditions, the audio buffer unit 1
6 (2048 bytes) is accumulated in the buffer (S24), and if the buffer on the decoder side outputs the pack and the buffer does not overflow (S25), the audio stream of the audio buffer unit 16 is transferred to the program stream. (S26).

As described above, authoring of a read-only disk DVD (creating data such as text, audio, images, etc.
The storage of the line 21 data in the conventional encoding apparatus used for editing and compiling a combined application) is to store the line 21 data prepared separately from the video signal in advance in the user data area of the GOP header. It is.

In recent years, the need for encoding in accordance with MPEG2 which is a read-only disc DVD standard has been increasing even in ordinary households.
2. Description of the Related Art A real-time encoding apparatus that encodes a video signal, which is a video signal of the TSC system, in real time and records the encoded video signal on a recording medium is showing signs of spreading to ordinary households.

FIG. 13 shows a configuration of a conventional real-time encoding apparatus for encoding a video signal on which line 21 data is superimposed in real time. The conventional real-time encoding apparatus extracts the text information such as English subtitle information superimposed on the vertical blanking period in the conventional encoding apparatus shown in FIG. 9 and outputs line 21 data. Is added, and other configurations and operations are the same as those of the conventional encoding device.

[0015]

However, in the prior art, in order to encode in real time from an analog video signal containing line 21 data, the line 21 data in the vertical blanking period is extracted, and the line 21 data is GO.
Must be stored in the P header. However, as shown in FIG. 14, the line 21 data corresponding to the GOP superimposed for each field may be extracted when the GOP header is created for storing the GOP header at the head of the stream including a plurality of pictures. Therefore, a GOP header without user data is created immediately after the start of encoding.

In addition, since the packet output condition of the packetizer is that if a certain amount of data is accumulated in the buffer, the pack is output, even if the line 21 data is extracted, the GOP header has already been created and there is a possibility that the packet is output as a program stream. Because of this, it cannot be stored in the GOP header currently being encoded, and is stored in the next GOP header.

As a result, the timing of extracting the line 21 data superimposed on the analog video signal is later than the timing of generating the GOP header, so that the line 21 data cannot be stored in the same time zone as the input image, and it is not possible to store the data in real time. In the case of encoding, the display timing of the character information of the input image and the encoded image of the line 21 data is shifted by a maximum of 1 GOP (about 0.5 seconds). There is a problem that the character information of the scene is displayed.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a device for encoding an analog video signal on which line 21 data is superimposed in real time, by using an analog video signal. A real-time encoding device and a real-time encoding method capable of storing superimposed line 21 data in user data at the same timing as an input image and displaying appropriate character information even when a scene changes in an encoded image The point is to provide.

[0019]

Means for Solving the Problems In order to solve the above problems, the present invention has the following constitution. The gist of the invention according to claim 1 is that an input video signal is encoded in real time to create a video stream composed of a GOP header and a plurality of pictures following the GOP header, and multiplexes the video stream and the audio stream. A character information extracting means for extracting character information included in the video signal, and an area for storing the character information extracted by the character information extracting means. Character information area securing means for securing the GOP header of the stream; character information storing means for storing the character information extracted by the character information extracting means in the area secured by the character information area securing means; And a real-time encoding device. The gist of the invention described in claim 2 is that the character information storage unit stores the character information extracted by the character information extraction unit after all of the plurality of pictures of the video stream are formed by encoding. 2. The real-time encoding apparatus according to claim 1, wherein the data is stored in the area secured by the character information area securing means. The gist of the invention according to claim 3 is that the character information area securing means includes:
Invalid dummy user data for securing the area for storing the character information is stored in the G of the video stream.
3. The method according to claim 1, wherein the information is created in an OP header.
The present invention resides in the described real-time encoding device. Claim 4
The gist of the invention described is that the character information storage means creates valid user data storing the character information extracted by the character information extraction means, and creates the user data by the character information area securing means. 4. The real-time encoding device according to claim 1, wherein the area of the dummy user data is overwritten. The gist of the invention according to claim 5 is that all of the character information corresponding to the plurality of pictures of the video stream is extracted by the character information extracting means, and is extracted by the character information extracting means by the character information storing means. The program stream is not created until all of the character information corresponding to the plurality of pictures in the obtained video stream is stored in the area secured by the character information area securing means. Item 5 is a real-time encoding device according to any one of Items 1 to 4. The gist of the invention described in claim 6 is that the character information is line 21 data superimposed on the 21st of a vertical blanking period of the video signal. Any one of the real-time encoding devices described above. The gist of the invention described in claim 7 is that a video stream composed of a GOP header and a plurality of pictures following the GOP header is created by encoding an input video signal in real time, and the video stream and the audio stream are multiplexed. A real-time encoding method for creating a program stream by extracting character information included in the video signal, and securing an area for storing the extracted character information when creating the GOP header of the video stream. And storing the extracted character information in the secured area. The gist of the invention described in claim 8 is that, after all of the plurality of pictures of the video stream are formed by encoding, the extracted character information is stored in the secured area. 7 is a real-time encoding method. The gist of the invention according to claim 9 is that invalid dummy user data for securing the area for storing the character information is stored in the GOP of the video stream.
A real-time encoding method according to any one of claims 7 to 8, wherein the method is created in a header. The gist of the invention according to claim 10 is characterized in that valid user data storing the extracted character information is created, and the user data is overwritten on the area of the created dummy user data. Claims 7 to 9
The real-time encoding method according to any one of the above.
Further, the gist of the invention according to claim 11 is to extract all the character information corresponding to the plurality of pictures of the video stream and secure the character information corresponding to the plurality of pictures of the video stream. 11. The real-time encoding method according to claim 7, wherein the program stream is not created until the program stream is stored in the area. Claim 1
The gist of the invention according to claim 2, wherein the character information is line 21 data superimposed on the 21st of a vertical blanking period of the video signal. The present invention resides in the described real-time encoding method.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an embodiment of a real-time encoding apparatus according to the present invention.

In this embodiment, a video decoder unit 10 for converting an analog video signal input from a video input into a digital video signal, and a compression protocol of MPEG2 specified in ISO13818-2 from a digitized video signal. Therefore, an MPEG2 video encoder unit 11 for creating and outputting a video stream, a video buffer unit 12 for temporarily holding the video stream, and line 21 data including character information such as English subtitle information are extracted from the vertical blanking period, A text slicer unit 19 for outputting line 21 data, a line 21 data buffer unit 13 for temporarily storing line 21 data, an audio ADC unit 14 for converting an analog audio signal input from an audio input into a digital audio signal,
The digitized audio signal is converted to ISO11172-
MPEG audio encoder 15 for outputting an audio stream in accordance with the MPEG1 compression protocol defined by MPEG3, an audio buffer 16 for temporarily holding the audio stream, and a packetizer for packing the data held in each buffer as a program stream. A stream creation control unit 1 that controls the MPEG2 video encoder unit 11, the MPEG audio encoder unit 15, and the packetizer unit 17 and writes line 21 data into the video buffer unit 12.

The stream creation controller 1 creates and outputs a video stream in the MPEG2 video encoder 11, creates and outputs an audio stream in the MPEG audio encoder 15, and outputs a packetizer 1.
In addition to controlling the creation and output of the program stream in 7, the MPEG2 video encoder 11 creates dummy user data that is invalid when creating the GOP header of the video stream, and secures an area for the user data. Further, the stream creation control unit 1 overwrites the user data including the line 21 data stored in the line 21 data buffer unit 13 in the user data area secured by the dummy user data, and also writes the GOP header of the GOP currently being encoded. Until the dummy user data is updated by extracting all the line 21 data included in the picture and overwriting the user data including all the extracted line 21 data, the video of the GOP header currently being encoded in the packetizer unit 17 is updated. Inhibits the packing of the stream.

Next, the operation of this embodiment will be described with reference to FIGS.
This will be described in detail with reference to FIG. FIG. 2 shows the MPE shown in FIG.
FIG. 3 is a flowchart for explaining a procedure of creating a video stream in the G2 video encoder unit, and FIG.
FIG. 4 is a flowchart for explaining a procedure for packing a video stream and an audio stream as a program stream in the packetizer shown in FIG. 1, and FIG. 4 is a flowchart showing a video signal and a video signal in the embodiment of the real-time encoding apparatus according to the present invention. FIG. 3 is an explanatory diagram for describing a relationship with a video stream.

First, parameters required for encoding are set in the initial setting (S1), and then a sequence header and a GOP header are created (S2, S3).

When a GOP header is created, the stream creation control unit 1 switches a 1-bit line 21 switch (line21_switc) shown in FIG. 7 as an area for storing line 21 data of a picture included in the GOP currently being encoded.
h) is set to '0b' (invalid) in advance as dummy user data, and the created user data has line 21 data (line21_dat
Field a data (line21_data) shown in FIG.
NUL for 1) and field 2 data (line21_data2)
The L data (data is '00000000b') is stored (S31). By creating dummy user data, if line 21 data exists in a picture included in the GOP header, the line 21 data can be stored in that area.

After the GOP header is created, a frame start process, a picture start process, and a slice start process for setting a code amount, a quantization step size, and the like as parameters necessary for coding, creating a header for each layer, and encoding. Perform (S6, S7, S8). Next, a macroblock process for performing actual encoding is performed (S9). The slice processing and subsequent steps are repeatedly executed, and the encoding of one picture is completed (S1).
0).

Each time the encoding of one picture is completed, the end of the sequence is checked (S11). If the sequence is completed, the encoding is terminated. If the sequence is not completed, it is checked whether the encoding of the number of pictures constituted by the GOP header has been completed. If there are still pictures in the GOP header, the frame start process is started. The encoding in one GOP header ends (S12).

After the encoding in the 1 GOP header is completed, the stream creation control unit 1
3 is checked (S32), and if the line 21 data is stored, the switch of the line 21 (line21_switc) is stored in the area reserved by the invalid dummy user data when the GOP header is created in the video buffer unit 12.
h) is '1b' (valid) and the field 1 data (lin
e21_data1) and field 2 data (line21_data2) are overwritten with the user data written in the line 21 data stored in the line 21 data buffer unit 13 (S33), and the video stream including the GOP header overwritten with the user data is programmed. The output for packing as a stream is permitted (S34).

When the line 21 data does not exist in the line 21 data buffer unit 13, the video stream including the GOP header in which the dummy user data is created with the switch of the line 21 (line21_switch) being invalidated is packed as a program stream. Output is permitted (S34). Then the next GOP
Is again executed from the sequence header generation in order to encode.

Next, the video stream stored in the video buffer section 12 and the audio stream stored in the audio buffer section 16 are packed by a packetizer section 17 to create a program stream. When creating a program stream in the packetizer 17,
Output of the video stream stored in the video buffer unit 12 is permitted so that the line 21 data included in the picture of the GOP header currently being encoded is extracted and the pack is not executed until the dummy user data is updated. It is checked whether or not the line 21 data of the GOP header of the video stream stored in the video buffer unit 12 has been determined based on whether or not the line 21 data of the GOP header has been determined (S35). The unit 17 ends the processing without packing.

As described above, the packetizer 17 suppresses the packing of the video stream currently being encoded and outputs it as a program stream. A time for writing the line 21 data accumulated in the line 21 data buffer unit 13 in the data area is secured. That is, as shown in FIG. 4, line 2 of all pictures included in the GOP header
A video stream is held in the video buffer unit 12 until one data is extracted, and the timing of packing and outputting as a program stream is determined after all pictures included in the GOP header have been encoded (after all lines 21 data has been extracted). ).

When the line 21 data of the GOP header has been determined, the buffer occupancy of the video buffer unit 12 and the audio buffer unit 16 (the amount of data stored in the buffer) and the virtual buffer occupancy of the decoder side are determined. Select the pack to output. First, the amount of data (2048 bytes) that can be packed in the video buffer unit 12 is accumulated in the buffer (S21), and if the buffer on the decoder side outputs the pack and the buffer does not overflow (S22), the video of the video buffer unit 12 The stream is output as a program stream (S2
3). If the video stream does not satisfy the above conditions, the amount of data (2
048 bytes) is accumulated in the buffer (S24), and if the buffer on the decoder side outputs a pack and the buffer does not overflow (S25), the audio stream of the audio buffer unit 16 is output as a program stream (S26). .

As described above, according to the present embodiment, in the apparatus for encoding an analog video signal on which line 21 data is superimposed in real time,
Adding an invalid user data in advance when creating the header to secure an area for storing the line 21 data extracted after creating the GOP header, and storing the line 21 data extracted from the analog video signal in the secured area. The line 21 superimposed on the analog video signal
The data can be stored in the user data at the same timing as the input image, and it is possible to display appropriate character information even if the scene changes in the encoded image.

It should be noted that MPE is used as an audio stream.
When the MPEG audio encoder unit 15 that outputs G audio outputs linear PCM as an audio stream, the audio ADC unit 14 may directly output the audio data to the audio buffer unit 16. When outputting as a stream, the MPEG audio encoder 15
May be replaced with a Dolby AC-3 encoder section,
When outputting MPEG2 audio as an audio stream, the MPEG audio encoder unit 15 may be replaced with an MPEG2 audio encoder unit.

It is apparent that the present invention is not limited to the above embodiments, and that the embodiments can be appropriately modified within the scope of the technical idea of the present invention. Further, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, but can be set to numbers, positions, shapes, and the like suitable for carrying out the present invention. In the drawings, the same components are denoted by the same reference numerals.

[0037]

According to the present invention, there is provided a real-time encoding apparatus and a real-time encoding method for encoding an analog video signal on which line 21 data is superimposed in real time. In addition, an area for storing the line 21 data extracted after the GOP header is created is secured, and the line 21 extracted from the analog video signal is stored in the secured area.
By storing the data, the line 21 data superimposed on the analog video signal can be stored in the user data at the same timing as the input image, and appropriate character information can be displayed even if the scene changes in the encoded image. This has the effect that it can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment of a real-time encoding device according to the present invention.

FIG. 2 is a flowchart for explaining a procedure of creating a video stream in the MPEG2 video encoder shown in FIG. 1;

FIG. 3 is a flowchart for explaining a procedure for packing a video stream and an audio stream as a program stream in the packetizer shown in FIG. 1;

FIG. 4 is an explanatory diagram illustrating a relationship between a video signal and a video stream in the embodiment of the real-time encoding device according to the present invention.

FIG. 5 is a diagram illustrating a 21st embodiment of a vertical blanking period of a video signal input to the embodiment of the real-time encoding apparatus according to the present invention.
FIG. 9 is a waveform chart showing a second waveform.

FIG. 6 is a diagram showing a configuration of an MPEG2 video stream to which the embodiment of the real-time encoding device according to the present invention conforms.

FIG. 7 shows a second example of the vertical blanking period of the video signal shown in FIG.
FIG. 4 is a configuration diagram showing a configuration of user data superimposed on a first waveform.

FIG. 8 is a configuration diagram showing a configuration of line 21 data shown in FIG. 7;

FIG. 9 is a block diagram illustrating a configuration of a conventional encoding device.

FIG. 10 is a flowchart for explaining a procedure of creating a video stream in the MPEG2 video encoder shown in FIG. 9;

FIG. 11 is a flowchart for explaining a procedure for packing a video stream and an audio stream as a program stream in the packetizer shown in FIG. 9;

FIG. 12 is an explanatory diagram for explaining a relationship between a video signal and a video stream in a conventional encoding device.

FIG. 13 is a block diagram illustrating a configuration of a conventional real-time encoding device.

FIG. 14 is an explanatory diagram for explaining a relationship between a video signal and a video stream in a conventional real-time encoding device.

[Explanation of symbols]

 Reference Signs List 1 stream creation control section 10 video decoder section 11 MPEG2 video encoder section 12 video buffer section 13 line 21 data buffer section 14 audio ADC section 15 MPEG audio encoder section 16 audio buffer section 17 packetizer section 18 controller section 19 text slicer section

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C059 KK00 LA00 MA00 PP04 RB01 RC02 RC34 SS02 UA02 5C063 AB03 AB07 AC01 AC05 CA09 CA11 CA20 CA23 CA40 DA03 EB01

Claims (12)

[Claims] 1. An input video signal is encoded in real time to create a video stream including a GOP header and a plurality of pictures following the GOP header, and multiplexes the video stream and the audio stream to create a program stream. A character information extracting means for extracting character information contained in the video signal; and a GOP header of the video stream for storing an area for storing the character information extracted by the character information extracting means. And character information storage means for storing the character information extracted by the character information extracting means in the area secured by the character information area securing means. Characteristic real-time encoding device. 2. The character information storage unit stores the character information extracted by the character information extraction unit after the plurality of pictures of the video stream are all formed by encoding by the character information area securing unit. 2. The real-time encoding apparatus according to claim 1, wherein the information is stored in the reserved area. 3. The character information area securing means creates invalid dummy user data for securing the area for storing the character information in the GOP header of the video stream. Or the real-time encoding device according to 2. 4. The character information storing means creates valid user data storing the character information extracted by the character information extracting means, and stores the user data in the character information area securing means. 4. The real-time encoding apparatus according to claim 1, wherein the area of the dummy user data is overwritten. 5. The character information extracting unit extracts all the character information corresponding to the plurality of pictures of the video stream, and the character information storing unit extracts the video stream extracted by the character information extracting unit. 5. The program stream is not created until all the character information corresponding to the plurality of pictures is stored in the area secured by the character information area securing means. A real-time encoding device according to 6. The real-time apparatus according to claim 1, wherein the character information is line 21 data superimposed on the 21st of a vertical blanking period of the video signal. Encoding device. 7. A video stream consisting of a GOP header and a plurality of pictures following the GOP header is created by encoding an input video signal in real time, and a program stream is created by multiplexing the video stream and the audio stream. Extracting a character information included in the video signal; securing an area for storing the extracted character information when creating the GOP header of the video stream; Storing the extracted character information in a real-time encoding method. 8. The real-time encoding according to claim 7, wherein after the plurality of pictures of the video stream are all formed by encoding, the extracted character information is stored in the secured area. Method. 9. The video data stream according to claim 7, wherein invalid dummy user data for securing the area for storing the character information is created in the GOP header of the video stream. Real-time encoding method. 10. The method according to claim 7, wherein valid user data storing the extracted character information is created, and the user data is overwritten on the area of the created dummy user data.
10. The real-time encoding method according to any one of claims 9 to 9. 11. Extracting all the character information corresponding to the plurality of pictures of the video stream and storing all the character information corresponding to the plurality of pictures of the video stream in the secured area. The real-time encoding method according to any one of claims 7 to 10, wherein the program stream is not created until the time. 12. The real-time apparatus according to claim 7, wherein the character information is line 21 data superimposed on the 21st of a vertical blanking period of the video signal. Encoding method.