JP2000228769A - Digital signal transmitter, its method, digital signal receiver, its method and served medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decode data encoded by a plurality of different systems with a correct phase. SOLUTION: An MPEG encoder section 103 outputs coding phase information denoting the upper left position of the range of a coded picture to an encode controller 102. The encode controller 102 describes the coding phase information to user data in an elementary stream. A variable length coding section 104 multiplexes the user data on the elementary stream outputted from the MPEG encode section 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital signal transmitting apparatus and method, a digital signal receiving apparatus and method, and a providing medium, and in particular, by inserting range information representing a range of an image to be encoded into a bit stream. ,
The present invention relates to a digital signal transmission apparatus and method, a digital signal reception apparatus and method, and a providing medium that can correctly decode even a bit stream encoded by a different method.

[0002]

2. Description of the Related Art When an image signal or an audio signal is encoded and transmitted, it is required to use ISO / IEC11172 (MPEG-1) or ISO / IEC13.
818 (MPEG-2) is often used. The image signal is converted to MPEG (Moving Picture Experts
Group coding) includes coding phase and bidirectional prediction.

[0003] As shown in FIG.
This is a code for defining an effective pixel area 2 as a range in which encoding is performed in the pixel area 1 of one image, and specifically, a first line of the effective pixel area 2 among all lines. (The line indicated by the arrow of V-phase [line] in FIG. 1) and the first sample of the first line of the effective pixel area 2 among all the samples (pixels) (H-phase [line] in FIG. 1) sample] (samples (pixels) indicated by arrows). When the last line of the pixel area 1 is set to V-Phase [Lmax] and the last sample (pixel) of the line of the pixel area 1 is set to H-Phase [Smax], encoding is performed, for example, in the vertical direction. , V-Phase [line] to (V-Phase [Lmax]-V-Phase [line] +1), and in the horizontal direction, from H-Phase [sample] to (H-Pha
Performed in the range up to se [Smax] -H-Phase [sample] +1).

In addition, in a general image signal of, for example, an NTSC television receiver, a frame of the image signal shown in FIG. 1 is composed of two fields (field 1 and field 1 shown in FIG. 2) as shown in FIG. 2). Field 1 displays, for example, data of odd lines, and field 2 displays data of even lines. The two fields are ancillary data and image data, respectively.
e data).

Auxiliary data is used for teletext data for teletext, time code, or closed caption data of subtitles for movies and the like for persons with hearing impairments, and is used for blanking intervals (for example, the first field of each field). 1
Lines 0 to 22) (in FIG. 2, each field is inserted into a predetermined line in each field, the lines are represented by numbers in order from the top in the field). Generally, a portion of a line located below the 23rd line of each field in the figure (a portion actually displayed as an image) is encoded as image data by the MPEG method or the like.

[0006] The above-mentioned MPEG coding method is applied only to image data, and the coding standard and auxiliary data are not clearly described (defined) in the MPEG standard. Therefore, the coding phase has a degree of freedom and differs depending on various applications.

A system configuration for encoding or decoding such an image signal will be described with reference to FIG.
The image data of the application A is encoded by the application A MPEG encoder 11 and output as an elementary stream (ES).
The data is decoded by the MPEG decoder 12. The image data of application B is the MPEG encoder 1 for application B
3 and output as an elementary stream (ES), which is decoded by the application B MPEG decoder 14.

That is, image data of a certain application is encoded by an encoder dedicated to the application (for example, an MPEG encoder 11 for application A), and converted into an elementary stream (ES) by a dedicated decoder (for example, Is output to the application A MPEG decoder 12).
Elementary stream (E
S) is decoded based on the decoder's information on the coding phase of the application.

Next, an auxiliary data transmission system which is currently mainstream will be described with reference to FIG. The image signal is input to the MPEG encoder 21 and separated by the separation unit 21 into image data and auxiliary data. The MPEG encoding unit 23 performs MPEG encoding of the image data. The auxiliary data is converted by the variable-length encoding unit 24 into the MPEG-format transport stream output from the MPEG encoding unit 23.
Inserted in user data. Since user data in the transport stream can be inserted (described) in units of coded image data (pictures), auxiliary data is inserted for each user data of each corresponding frame of coded image data.

[0010] The transport stream including the user data into which the auxiliary data has been inserted is transmitted via a predetermined transmission path and input to the MPEG decoder 25. The variable length decoding unit 26 in the MPEG decoder 25 separates auxiliary data and image data. The image data is decoded by the MPEG decoding unit 27, combined with the auxiliary data by the combining unit 28, and output as an image signal to a display device (not shown).

Next, prediction of the MPEG system will be described.
A picture of encoded image data generated based on bidirectional prediction is called a B picture. The B picture is predicted and generated from two pieces of reference image data located before or after in time. A picture of coded image data generated based on forward prediction is called a P picture. The P picture is predicted and generated from one piece of reference image data located earlier in time. A picture of the coded image data in which the prediction is not performed and the image data is coded (intra-coded) as it is is called an I picture. That is,
The input image data is encoded into encoded image data of one of a B picture, a P picture, and an I picture.

FIG. 5 shows bidirectional prediction and forward prediction.
This will be described with reference to FIG. In the example of FIG. 5, one GOP (Group
of Picture) is composed of nine pictures. The upper part of FIG. 5 shows a prediction structure indicating the direction (dependency) of prediction when encoded image data is generated, and the lower part of FIG. 5 shows the order in which image data is actually encoded. 4 shows the coding structure shown. Since a B picture or a P picture is predicted and generated from temporally preceding or succeeding image data, encoding cannot be performed using only a B picture or a P picture. That is, since a B picture or a P picture is encoded image data whose data is a difference from reference image data,
Image data cannot be decoded only with B pictures or P pictures.

The prediction dependency will be described in detail. For example, in GOP (N-1), a B picture whose display order is the first is a third I picture from the top and a GOP (N-2 not shown). ) (The GOP immediately before GOP (N-1)) is predicted and coded from the last P picture. Similarly, the second B picture from the top is the third I picture from the top,
It is predicted and coded from the last P picture of the GOP (N-2) not shown. The third I picture from the top is
It is coded as it is (intra coded). 4 from the beginning
The fifth and fifth B pictures are predicted and encoded from the third I picture from the beginning and the sixth P picture from the beginning. The sixth P picture from the top is predicted and encoded from the third I picture from the top.

That is, in the prediction structure, in order to encode a B picture (for example, a first B picture and a second B picture from the top), reference image data for prediction (for example, a third I picture and a GOP (The last P picture of (N-2)) needs to be coded first. That is,
The encoding must be performed in the order of the encoding structure as shown in the lower part of FIG. Therefore, at the time of encoding (encoding), the MPEG encoder uses reference image data (third I picture from the top) necessary to encode two continuous B pictures existing between an I picture and a P picture. ) Needs to be buffered (the start of encoding is delayed until an I picture is input). Due to this buffering, when encoding the input image signal in the MPEG encoder, a delay time of the number of B pictures (= 2) +1 (three in total) sandwiched between the reference image data occurs.

The delay that occurs in the MPEG encoder will be described in more detail with reference to FIG. The upper part of FIG. 6 shows the input order (display order) and the type of the input image (image data) in the MPEG encoder 31, and the middle part of FIG. 6 shows the encoding in which the input image (image data) is encoded. This indicates the order of the image data.

The MPEG encoder 31 operates until the P picture at time t4 is input (the number of B pictures (= 2) +1
Then, the encoding of the I picture input at time t1 is delayed (the above-described buffering is performed).
That is, the MPEG encoder 31 outputs the time t1 at the time t4.
Is encoded at time t5 at time t5.
4, the P picture input at time t6 is encoded, the B picture input at time t2 is encoded at time t6, and the B picture input at time t3 is encoded at time t7. afterwards,
The MPEG encoder 31 sequentially encodes the input image in the order of the encoded image data in the middle stage of FIG.

As described above, the MPEG encoder 31 sequentially encodes an input image from reference image data necessary for prediction. That is, in the MPEG encoder 31, the input images (image data) are rearranged from the order of the input images to the order of the images to be encoded, and as shown in the middle part of FIG. Is output to the MPEG decoder 32 as a bit stream.

As described above, the order in which the input images are encoded and the order in which they are displayed do not match.
A DTS (Decoding Time Stamp) representing an encoding order and a PTS (Presentation Time Stamp) representing a display order are inserted into a transport stream. To further explain the relationship between the encoding order and the display order of the input images, assuming that the encoding order is expressed in units of frames, as shown in FIG. 6, the input images are numbered in the encoding order, The value of the coding order of the I picture coded at time t4 is “1”, the value of the coding order of the P picture coded at time t5 is “2”, and
The value of the encoding order of the B picture encoded in 6 is “3”
Becomes Hereinafter, the encoding order is numbered in the same encoding order. Although the DTS does not represent the encoding order on a frame basis, it almost corresponds to this encoding order. The DTS is also used by the MPEG decoder 32 as a decoding order when a bit stream is multiplexed with an audio signal or the like and output.

The display order is the order in which the image data is decoded and displayed (the same order as the input image data). Specifically, the display order of the I picture (encoding order = 1) to be encoded at time t4 must be displayed when the P picture (encoding order = 2) is encoded at time t5. Therefore, the same value as the encoding order of the P picture "
2 ". The display order of the P pictures (encoding order = 2) encoded at time t5 must be displayed when the P pictures (encoding order = 5) are encoded at time t8. , The same value as the encoding order of the P picture ”
5 ". The B picture encoded at time t6 (coding order = 3) must be immediately decoded and displayed as soon as it is coded, so that the coding order and the display order are the same. The value of the display order is “3.” Similarly, the B picture (encoding order = 4) encoded at time t7 is also
Display order = encoding order = 4. The PTS does not represent the display order in frame units, but almost corresponds to this display order. The PTS is also used by the MPEG decoder 32 as an order of outputting (displaying) after decoding.

In the MPEG decoder 32, of the two I-pictures or P-pictures whose coding order is continuous, the first picture is displayed when the second picture is decoded. For example, the first I picture (coding order = 1, display order = 2) of the encoded image data in the bit stream output from the MPEG encoder 31 and the second P picture (coding order = 2, When the display order = 5), the encoding order is continuous and the second P picture is encoded (time t).
5) The first I picture is decoded and displayed.

As described above, since the MPEG encoder 31 knows the prediction structure (the number of B pictures sandwiched between the reference image data) of the input image (image data), the encoding order (DTS) is added to the image data. And display order (PTS).

Transmission of an MPEG encoded bit stream in a studio such as a broadcasting station with the system configuration shown in FIG. 7 has been considered. MPEG encoder 42 in studio 41, MPEG encoder 43, MPEG decoder 4
4 and the MPEG decoder 45 are SDTI-CP (S
erial Data Transfer Interface-Content Package)
It is connected to an SDTI-CP network (for example, a network constituted by a coaxial cable) 50 via the interfaces 46 to 49. SDTI-CP Network 50
Is based on SDI (Serial Data Interface) 27
It has a transmission speed of 0 Mbps and can transmit an MPEG elementary stream (ES) as it is, and is suitable for a closed network such as in a studio.

In the studio 41, for example, the MPEG encoder 42 converts the MPEG-encoded elementary stream (ES) into an MPEG stream via the SDTI-CP network 50.
The data can be transmitted to the decoder 44 and the MPEG decoder 45.

The elementary stream (ES) transmitted through the SDTI-CP network 50 has the structure shown in FIG. 8, and is composed of image data (portions shaded in FIG. ) And audio data (portions with dark shadows in FIG. 8) are packed, and editing can be performed easily at frame boundaries separated by frame syncs (dotted lines in FIG. 8). The image data and the audio data in the elementary stream (ES) are data subjected to intra (intra-frame coding) processing.

The system of the studio 41 shown in FIG. 7 has MPEG encoders 42 and 43 and MPEG decoders 44 and 45.
Is connected to the SDT via the SDTI-CP interfaces 46 to 49.
As shown in FIG. 3, it is connected to the I-CP network 50 and dedicated encoder (for example, MPEG encoder 11 for application A) and decoder (for example, MPEG decoder 1 for application A) for each application.
The configuration is different from the system in which 2) corresponds one-to-one. That is, a decoder (for example, the MPEG decoder 44 in FIG. 7) is an elementary stream (ES) in which image signals of various applications are encoded by an encoder (for example, the MPEG encoder 42 or the MPEG encoder 43 in FIG. 7). Can receive.

The system configuration of FIG. 7 will be described with reference to FIG. 9 corresponding to the system configuration of FIG. 3. The elementary stream (ES) encoded by the application A MPEG encoder 42 and the application B The elementary stream (ES) encoded by the MPEG encoder 43 is transmitted to the SDTI-CP interfaces 46 and 47, respectively.
Is input to SDTI-CP interfaces 46 and 47
Each elementary stream (E
S) to an SDTI format elementary stream (E
S), and transmit via the SDTI-CP network 50. The SDTI-CP interface 48 converts the elementary stream (ES) in the SDTI format into an MPEG-encoded elementary stream (ES) and outputs it to the MPEG decoder 44.

The MPEG decoder 44 receives the input elementary streams (ES) for application A.
And the elementary stream for application B (E
Decrypt S).

When the auxiliary data is inserted into the user data in the transport stream, the auxiliary data is inserted for each frame of the corresponding coded image. Become.

The signal to be encoded is a signal that has been subjected to a 3-2 pull-down process (for example, a process of converting a movie image signal having a frame rate of 24 Hz into an NTSC image signal having a frame rate of 30 Hz). In some cases, the signal is such that, as shown in FIG. 10, each frame of 24 Hz is alternately a two-field frame in which no repeat field is created or a three-field frame in which a repeat field is created. , And a signal of 30 Hz.

For example, the MPEG encoder 21 shown in FIG.
-2 When an image signal converted to a frame rate of 30 Hz by pull-down processing is input, repetition of a field is detected, coding is performed in units of the original coding frame of 24 Hz, and corresponding to the processing, Flag (Repeat_fir
st_field, Top_field_first).

The flag “1” of the Repeat_first_field is
Repeat means that the repeat field was created
"0" of the flag of _first_field means that a repeat field has not been created. Top_field_first
Indicates whether the first field among the fields constituting the frame is the top field or the bottom field. Top_field_
The first flag “1” indicates that the top field has a temporally earlier frame structure than the bottom field, and the Top_field_first flag “0” indicates that the bottom field has a temporally earlier frame structure than the top field. It represents that.

As shown in FIG. 10, when the frame of the original signal is a frame of three fields, one corresponding encoded frame includes two fields (3-
2) There is a field generated by the copy through the pull-down process and a field of the copy source. However, when the three fields constituting this original one frame are encoded in units of encoded frames, the auxiliary data for each encoded frame is encoded in units of encoded frames.
Since one piece of auxiliary data is described in the user data, even if different auxiliary data is described in the same phase field of the original signal, the different auxiliary data cannot be distinguished.

[0033]

In FIG. 9, the MPEG decoder 44 needs to decode a plurality of input elementary streams (ES) corresponding to each application.
You usually don't know any information about hase. Therefore, the decoded image signals of various applications are
The decoding cannot be performed with an appropriate phase corresponding to the effective pixel area 2 shown in FIG. That is, since the elementary stream (ES) in which the image data of various applications is encoded does not include the information on the coding phase, it is difficult for the MPEG decoder 44 to decode the image signal with the same phase. Becomes

The present invention has been made in view of such a situation, and is intended to insert a coding phase of an image signal into a bit stream, thereby decoding a plurality of bit streams of different encoding systems with an appropriate phase. To make it possible.

[0035]

According to a first aspect of the present invention, there is provided a digital signal transmission apparatus which encodes an image signal in a predetermined range of an image, and a range which is encoded by the encoding means. It is characterized by including insertion means for inserting the corresponding range information into the bit stream, and transmission means for transmitting the bit stream with the range information inserted by the insertion means.

According to a fourth aspect of the present invention, in the digital signal transmission method, an encoding step of encoding an image signal in a predetermined range of the image, and range information corresponding to the range encoded in the encoding step are: The method includes an insertion step of inserting the bit stream into the bit stream, and a transmission step of transmitting the bit stream in which the range information is inserted in the insertion step.

According to a fifth aspect of the present invention, there is provided the providing medium, comprising: an encoding step of encoding an image signal in a predetermined range of an image; and a range information corresponding to the range encoded in the encoding step. An insertion step to insert into the
And a transmission step of transmitting a bit stream in which the range information has been inserted in the insertion step.

According to a sixth aspect of the present invention, there is provided a digital signal receiving apparatus comprising: extracting means for extracting range information corresponding to a range in which an image signal is to be encoded, of an image inserted into a bit stream; Decoding means for decoding a bit stream based on the extracted range information.

According to a seventh aspect of the present invention, there is provided a digital signal receiving method comprising: an extracting step of extracting range information corresponding to a range in which an image signal is to be encoded, of an image inserted into a bit stream; Decoding a bit stream based on the extracted range information.

[0040] The providing medium according to claim 8 is extracted in an extraction step of extracting range information corresponding to a range in which an image signal is to be encoded, of the image inserted in the bit stream. Based on the range information
And a computer readable program for executing a process including a decoding step of decoding a bit stream.

The digital signal transmission device according to claim 1,
In the digital signal transmission method according to the fourth aspect and the providing medium according to the fifth aspect, the image signal is encoded, and range information indicating an encoding range of the encoded image signal is inserted into the bit stream. Transmitted.

A digital signal receiving apparatus according to claim 6,
In the digital signal receiving method according to the seventh aspect and the providing medium according to the eighth aspect, the bit stream is decoded in accordance with the range information inserted in the bit stream.

[0043]

FIG. 11 shows an example of a system for transmitting an MPEG-encoded bit stream between a studio 41 and a studio 71 located at a distance from each other. The parts corresponding to are denoted by the same reference numerals. In this example, the network in each studio is connected to a satellite or an ATM (Asynchronous Transfer Mod) via a multiplexer (hereinafter, referred to as TS MUX / DEMUX).
The bit stream can be transmitted by connecting to a public network such as e). Since the MPEG encoder 72 to the SDTI-CP interface 79 of the studio 71 corresponds to the MPEG encoder 42 to the SDTI-CP interface 49 of the studio 41 in FIG. 7, the description is omitted here.

The elementary stream (ES) in the SDTI-CP network 50 is, as shown in FIG.
The UX / DEMUX 61 converts it into a 188-byte transport stream (TS), transmits it via a predetermined transmission medium, and transmits the transport stream (T
S) is converted by the TS MUX / DEMUX 62 into an elementary stream (ES) in the SDTI format. FIG.
In the figure, the lightly shaded portion indicates a packet of image data, the darkly shaded portion indicates a packet of audio data, and the unshaded portion indicates a packet of free data.

In FIG. 11, the elementary stream (ES) output from the MPEG encoder 42 in the studio 41
However, TS MUX / DEMUX61 uses transport stream (T
Until the conversion to S) will be described with reference to FIG. M
MPEG video encoder 42A in PEG encoder 42
Outputs an elementary stream (ES) of image data encoded by MPEG to the SDTI-CP interface 46,
The audio encoder 42B converts the elementary stream (ES) of the audio data into an SDTI-CP interface 46.
Output to The SDTI-CP interface 46 converts the input elementary stream (ES) into an elementary stream (ES) in an SDTI-based format, and
-Output to the SDTI-CP interface 51 via the CP network 50. SDTI-CP interface 51
The format ES is converted to an MPEG-encoded elementary stream (ES) and output to the TS MUX / DEMUX 61. TS
The MUX / DEMUX 61 converts the MPEG encoded elementary stream (ES) into a 188-byte transport stream (TS) and outputs it to a transmission medium.

In FIG. 11, a transport stream (TS) transmitted from a TS MUX / DEMUX 61 is input to a TS MUX / DEMUX 62 via a public network such as an ATM, and is transmitted to an MPEG.
It is converted into an encoded elementary stream (ES).
In the SDTI-CP interface 81, the MPEG-encoded elementary stream (ES) is converted into an SDTI-formatted elementary stream (ES) and output to the SDTI-CP network 80 of the studio 71. The MPEG decoder 74, via the SDTI-CP interface 78,
The elementary stream (ES) transmitted from the studio 21 can be received.

In the system shown in FIG.
When an image signal is transmitted between the STA and the studio 71, a multiplexer (for example, the TS MUX / DEMUX 61 in FIG. 11) includes an elementary stream (ES) in which the image data is encoded.
Since only the input is input, the multiplexing device does not know the information of the rearrangement of the encoding order performed in the encoder (for example, the MPEG encoder 42 in FIG. 11). For this reason, the multiplexing device receives the input elementary stream (ES).
Must be interpreted to convert the elementary stream (ES) into the transport stream (TS).

The process for interpreting the elementary stream is a process for grasping the coding structure of the image signal. That is, the same processing as when the input image is buffered and encoded by the encoder described above and converted into a bit stream is also required in the multiplexing device. Due to the buffering process in the multiplexing device, a delay occurs until decoding of image data in a subsequent stage, and real-time processing becomes difficult.

With reference to FIG. 14, a description will be given of a delay which occurs in the multiplexing apparatus and causes a problem in the system configuration. When a bit stream coded by the encoder in the coding order shown in FIG. 14 is input to the multiplexing device, the multiplexing device sets two consecutive I pictures (time t
4) and a P picture (time t5) are input, and two B pictures (time t6 and time t6) sandwiched between them are further input.
Until a P picture (time t8) is input following 7), the display order cannot be determined. That is, the multiplexing device does not know the coding structure (a structure in which two B pictures are sandwiched between an I picture and a P picture) as shown in FIG. When the next P picture (time t8) is input (when it is confirmed that the input of the B picture has been completed), the time t
4 can determine the display order (PTS) of the I picture input.

That is, in this multiplexing apparatus, it is possible to determine the display order = 2 of the I picture having the coding order = 1 only at time t8. For this reason, in the multiplexing device, a delay of an appearance cycle (= 4) of two consecutive I pictures or P pictures + 2 B pictures occurs. Since this delay is newly generated separately from the delay in the encoder, a large delay of encoder delay (= 3) + multiplexer delay (= 4) = 7 occurs in the entire system.

Therefore, in the present invention, the order information including the encoding order and the display order is superimposed on the elementary stream as PictureOrder Info. This will be described in detail later.

FIG. 15 shows a configuration example of an MPEG encoder 42 to which the present invention is applied. The separating unit 101 of the MPEG encoder 42 separates the image data and the auxiliary data from the input image signal, and converts the image data into the MPEG encoding unit 1.
03, and outputs the auxiliary data to the encode controller 1
02 is output. The MPEG encoding unit 103 encodes the input image data according to the MPEG method, and also includes a DTS_counter indicating an encoding order, and a PTS indicating a display order.
A POI (Picture Order Information) including _counter is output to the encoding controller 102. In addition, the MPEG encoding unit 103 encodes a coding phase (V-Phase, H-Phas, H-Phas
e)) is supplied to the encode controller 102.

The encoding controller 102 adds, to the auxiliary data supplied from the separating unit 101, a Field ID for identifying a field to which the auxiliary data belongs, and a Line_number for a line in which the auxiliary data is inserted.
POI and Codi supplied from the PEG encoder 103
ng Phase Information (CPI) is processed appropriately and user data
Variable-length encoding unit 104
And multiplex it.

The variable length encoding unit 102 performs variable length encoding on the encoded image data supplied from the MPEG encoding unit 103, and
02 is inserted into the elementary stream of the image data. The elementary stream output from the variable length coding unit 104 is transmitted to the transmission buffer 1
05 is output.

FIG. 16 shows a configuration example of an MPEG decoder 44 to which the present invention is applied. The receiving buffer 111 temporarily buffers the input data, and then outputs the data to the variable-length decoding unit 112. The variable length decoding unit 112 separates image data and user data from the input data,
The image data is output to the MPEG decoding unit 114, and the user data
a is output to the decode controller 113. The decode controller 113 separates the POI and CPI from the user data and outputs them to the MPEG decoding unit 114. Also,
The decode controller 113 outputs the auxiliary data separated from the user data to the synthesizing unit 115. The MPEG decoding unit 114 converts the image data input from the variable length decoding unit 112 into the PO data input from the decode controller 113.
Decoding is performed with reference to I and CPI, and the decoded result is output to the synthesis unit 115. The combining unit 115 combines the auxiliary data supplied from the decode controller 113 with the image data supplied from the MPEG decoding unit 114, and outputs the combined data.

The operation of the MPEG encoder 42 and the MPEG decoder 44 will be described below.

The operation of describing the CPI in the user data and superimposing and outputting the CPI on the elementary stream (ES) will be described with reference to FIG. In the encoded elementary stream (ES), CPI (V-Phase and H-Phase which are data indicating an effective pixel area in an image signal format) is described in user data (FIG. 15).
Of the variable length encoding unit 104
2 is described in user data) and output to the SDTI-CP interface 46. The MPEG encoder 43 for the application B is also configured in the same manner as the MPEG encoder 42, and converts the image signal of the application B into an elementary stream (ES) that is encoded.
The CPI is described as user data and output to the SDTI-CP interface 47.

An example of the configuration of the SDTI-CP interface 46 will be described with reference to FIG. 18 (other SDTI-CP interfaces have the same configuration). The decoding unit 121
The MPEG-encoded elementary stream (ES) input from the MPEG encoder 42 is separated into encoding parameters and image data, the image data is decoded, and output to the encoding parameter multiplexing unit 122 together with the encoding parameters. . The coding parameter multiplexing unit 122 generates and outputs an SDTI-CP based elementary stream (ES) from the image signal and the coding parameters.

When an SDTI-CP-based elementary stream (ES) is input to the SDTI-CP interface 46, the coding parameter separation unit 123 separates image data and coding parameters from the elementary stream (ES). Then, each is output to the encoding unit 124. The encoding unit 124 encodes the image data using the encoding parameters, and encodes the elementary stream (E
S) or output as MPE
Output as a G-encoded transport stream (TS).

The SDTI-CP interfaces 46 and 47 are MPE
G-encoded elementary stream (ES) is converted to SDTI
It is converted into an elementary stream (ES) in the format and transmitted via the SDTI-CP network 50. SDT
The I-CP interface 48 converts the elementary stream (ES) in the SDTI format into an elementary stream (ES) encoded by MPEG and outputs the same to the MPEG decoder 44.

The MPEG decoder 44 decodes the input elementary stream (ES) of the application A or the elementary stream (ES) of the application B, and is described in each of the elementary streams (ES) (FIG. 16). The decoding is performed so that the image signal is arranged in the effective pixel area based on the CPI output by the decoding controller 113).

Each of the MPEG encoders 42 and 43 converts the CPI of the image signal of the application encoded by the user data into the MPEG encoded elementary stream (ES).
By describing in a, the CPI can be transmitted together with the image data. MPEG encoders 42 and 43
Has a function of transmitting CPI, so that various applications can be encoded and transmitted.

The MPEG decoder 44 separates and interprets the CPI inserted in the MPEG-encoded elementary stream (ES) to appropriately convert images of applications having various coding phases into an effective pixel area. The decoding process can be performed so as to be arranged in

In the embodiment of the present invention, the CP
I is the user of the MPEG encoded elementary stream
Although inserted into the data, it may be inserted into the bit stream by another method.

Next, the operation of the MPEG encoder 42 for identifying a plurality of auxiliary data for each field will be described with reference to FIG. It is assumed that auxiliary data is inserted in each field of the original signal (30 Hz) of the encoded frame on which the 3-2 pull-down process has been performed. When the original signal (30 Hz) having the auxiliary data is encoded into the encoded frame (24 Hz) at the original frame rate, the auxiliary data described in two or three fields included in each encoded frame is obtained. , An identifier corresponding to the encoded field is added as field_ID (the value of the counter of 0 to 2) (field_ID is added to the auxiliary data by the encoding controller 102 in FIG. 15), and transmitted together with the auxiliary data. You. This field_ID
Is added to the auxiliary data to identify which field in the encoded frame the auxiliary data corresponds to.

More specifically, since the number of fields in the first coded frame in FIG. 19 is two, there are two auxiliary data. An encoded frame is generated from two fields, and a 2D frame corresponding to the encoded frame is generated.
Field_ID for each auxiliary data of one field
"0" or "1" is added.

Since the number of fields in the field of the second coded frame from the top is three, there are three auxiliary data. An encoded frame is generated from three fields, and the auxiliary data of each of the three fields corresponding to the encoded frame is represented by field_ID as “field_ID”.
0 ”,“ 1 ”or“ 2 ”is added.

That is, for one encoded frame,
Instead of generating one auxiliary data, the same number of auxiliary data as the number of fields included in the encoded frame is generated, and a field_ID is added to each. As a result, a plurality of auxiliary data included in the same encoded frame is identified in the encoded frame by the added field_ID, so that even if each auxiliary data includes different information, it can be identified. It will not go away.

In the MPEG encoder 42, the image data is
The data is encoded by the EG encoding unit 103 and is variable-length encoded by the variable-length encoding unit 104. Further, the field_ID and the line number (Line_number) in which the auxiliary data is inserted are added to the auxiliary data by the encode controller 102, and the ancil is included in the user data in the elementary stream.
Inserted as lary data. Thus, a plurality of auxiliary data can be identified and transmitted.

In the MPEG decoder 44, the user data in the MPEG-encoded elementary stream is separated by the variable length decoding unit 112 and supplied to the decode controller 113. The decode controller 113 sets the field_ID and Line_numbe of the ancillary data inserted in the user data.
Based on r, a plurality of auxiliary data are identified and separated, and output to the synthesizing unit 115. The synthesizing unit 115 synthesizes the image data decoded by the MPEG decoding unit 114 and the corresponding auxiliary data (text data), and outputs the synthesized data.

The MPEG encoder 42 generates a POI for managing the encoding order and the display order as shown in FIG. 20 in order to reduce the delay of the entire system.

For example, when the image data input to the MPEG encoding unit 103 of the MPEG encoder 42 is an image signal converted to a frame rate of 24 Hz by 3-2 pull-down processing, as shown in FIG. Each frame is managed by various flags (Repeat_first_field, Top_field_first).

The flag “1” of the Repeat_first_field is
A repeat field needs to be created, and the flag “0” of Repeat_first_field means that a repeat field need not be created. Top_
The field_first flag indicates whether the first field among the fields constituting the frame is the top field or the bottom field. “1” of the Top_field_first flag indicates that the top field has a temporally earlier frame structure than the bottom field, and “1” of the Top_field_first flag is “1”.
"0" indicates that the bottom field has a temporally earlier frame structure than the top field.

FIG. 20A is specifically described. First, the Frame input to the MPEG encoding unit 103
The encoded image data type of the No. 1 encoded frame is an I picture, and two fields (a top field and a bottom field) of the I picture are obtained by copying the top field and creating a repeat field.
Since it needs to be converted to a field, the corresponding Repeat
The flag of _first_field becomes “1” and Top_field_firs
The flag of t becomes "1".

The coded image data type of the coded frame of Frame No. 2 is a B picture, and since there is no need to generate a repeat field in this B picture,
The flag of peat_first_field is set to “0” and the flag of Top_field_first is set to “0” because the bottom field is a frame earlier in time than the top field. The value of the Top_field_first flag at this time is 3-
It is not related to the 2 pull-down processing.

The coded image data type of the coded frame of Frame No. 3 is B picture, and in the B picture of Frame No. 3, the bottom field is copied to create a repeat field, and the coded frame is converted into three fields. Have been. Therefore, the flag of Repeat_first_field is set to “1” and the flag of Top_field_first is set to “0”.
It is said.

The coded image data type of the coded frame of Frame No. 4 is P picture, and no repeat field is created for this P picture.
The at_first_field flag is set to “0” and Top_field_fi
The rst flag is set to 1.

The MPEG encoding unit 103 is configured as shown in FIG.
When image data that has been subjected to the 3-2 pull-down processing as shown in (1) is input, a built-in counter PTS_counte
The number of fields is counted by r, and the value PTS_counter is output to the encoding controller 102 as a display order. The counter PTS_counter performs a counting operation after increasing from 0 to 127 and then returning to 0 again. Therefore, the value of the counter PTS_counter changes as shown in FIG.

More specifically, the first input Fr
The value of the PTS_counter of the I picture of ame No1 is the value “0”. The value of the PTS_counter of the B picture of Frame No. 2 input second from the top is the PTS of the I picture of Frame No. 1.
When the value of TS_counter is “0”, the number of fields of the P picture is 3
Is added to "3" (= 0 + 3).

The value of the PTS_counter of the B picture of Frame No. 3 input third from the beginning is the value “5” obtained by adding the number of fields 2 of the B picture to the value of “3” of the PTS_counter of the B picture of Frame No. = 3 + 2). PTS_c of P picture of FrameNo4 input fourth from the beginning
ounter value is PTS_counter of B picture of Frame No3
Is obtained by adding the number of fields 3 of the B picture to the value "5" of the B picture "8" (= 5 + 3). The value of the PTS_counter for the B picture of Frame No. 5 and thereafter is similarly calculated.

Further, the MPEG encoding unit 103 counts the frames encoded by the built-in counter DTS_counter, and outputs the counted result to the end controller 102.

More specifically, with reference to FIG. 20C, the DTS_counter value 12 of the I picture of Frame No. 1
5 is a display order PT in which the I picture of Frame No. 1 is displayed.
When S_counter = 0 is used as a reference, it is necessary to perform encoding before the appearance cycle of one frame (in the case of FIG. 14, the value of the encoding order of the leading I picture is “1”, and The value of the order is “2”, and the value of the encoding order needs to be one frame earlier than the value of the display order.) That is, since the I picture has three fields,
The value of DTS_counter is a value "125" (D
TS_counter is represented by a modulo of 2 ⁷ (= 128), so its value circulates between 0 and 127).

The value of the DTS_counter of the P picture of Frame No. 4 encoded next to the I picture of Frame No. 1 is Frame
The value 0 (= 128 = 125 +) obtained by adding the number of fields of the I picture 3 to the DTS_counter value 125 of the I picture of No1
3).

The value of the DTS_counter of the B picture of Frame No. 2 coded next to the P picture of Frame No. 4 is B
PTS_counter = DTS_counter for pictures, PT
It is the same as the value of S_counter, and its value is “3”.
Similarly, encoded next to the B picture of Frame No. 2,
The DTS_counter value of the B picture of Frame No. 3 is also PTS_cou
nter and the value is “5”. Hereinafter, the values of the DTS_counter for the P pictures of Frame No. 7 and thereafter are calculated in the same manner, and the description thereof is omitted here.

The MPEG encoding unit 103 includes flags Repeat_first_field, Top_field_first,
The counters PTS_counter and DTS_counter are output to the encode controller 102 as POI.

Here, the MPEG 7 of the studio 41 at a remote location shown in FIG.
In one MPEG decoder 74, the SDTI-CP network 50,
The encoding sequence and the display sequence of a system for transmitting an image signal using the network 80, the TS MUX / DEMUXs 61 and 62, and the ATM will be described with reference to FIG.

The MPEG video encoder 42A in the MPEG encoder 42 outputs an elementary stream (ES) of the image data encoded by MPEG, and inserts the POI into user data in the elementary stream (ES). (The encode controller 102 in FIG. 15 describes the POI data in the user data, outputs the POI data to the variable length encoding unit 104, and multiplexes the data). An audio encoder 42B in the MPEG encoder 42 encodes audio data and outputs it as an elementary stream (ES). SDTI-C
The P interface 46 is an MPEG video encoder 42A
, And converts the elementary stream (ES) from the audio encoder 42B into an elementary stream in the SDTI format, and outputs the elementary stream (ES) from the audio encoder 42B to the SDTI-CP network 50.

The SDTI-CP interface 51 receives an input elementary stream (ES) in the SDTI format.
Is converted to an elementary stream (ES) of MPEG encoding (as described as the operation of the SDTI-CP interface 46 with reference to FIG. 18) and output to the TSMUX / DEMUX 61. TS MUX / DEMUX 61 is an elementary stream (E
Referring to the POI inserted in S), the value of PTS_counter is set to PTS (Presentation TimeStamp), and DTS_count
The value of er is converted to a DTS (Decoding Time Stamp), multiplexed, and a transport stream (TS) composed of 188-byte packets is generated and output (accordingly, the transport stream (TS TS)
Includes PTS and DTS, not PTS_counter and DTS_counter).

The TS MUX / DEMUX 61 can immediately perform the multiplexing processing without performing the buffering processing by interpreting the POI inserted in the elementary stream (ES). In the DEMUX 61, no new delay occurs. Also, since the POI is inserted in the elementary stream (ES),
The TS MUX / DEMUX 61 transmits the POI to the subsequent stage.
May be omitted from the bit stream.

A TS MUX / DEMUX 62 shown in FIG. 11 separates image data and audio data from a transport stream (TS) input via a public network such as an ATM, and outputs an MPEG encoded elementary stream (ES). Convert to TS M
The UX / DEMUX 62 also assigns PTS, DTS to PTS_counter, DTS_cou.
Converted to nter, user data of elementary stream
And outputs it to the SDTI-CP interface 81. SDT
The I-CP interface 81 converts the MPEG-encoded elementary stream (ES) into an elementary stream (ES) in the SDTI format, and
Output to the network 80. MPEG decoder 74 (MPEG
The same configuration as the decoder 44) receives and decodes the transmitted elementary streams (ES) of the image data and the audio data via the SDTI-CP interface 78.

The MPEG decoder 74, like the TS MUX / DEMUX 61, interprets the POI inserted in the elementary stream (ES) and immediately decodes it without performing the above-described buffering processing (see FIG. 16). Based on the POI output from the decode controller 113, the MPEG decoding unit 11
4 can decode the image data), and no new delay occurs in the MPEG decoder 74. In other words, the MPEG video encoder 42A inserts the POI into the elementary stream together with the MPEG-encoded elementary stream (ES) and outputs the POI. The multiplexing process or the decoding process can be performed immediately by interpreting, and the delay of the entire system is reduced by the MPEG encoder 4.
2 can be suppressed to only the delay of the number of B pictures (= 2) + 1 = 3. That is, in a system including such encoding, multiplexing, and decoding, the delay can be theoretically minimized.

In the system configuration shown in FIG. 21, by using the SDTI-CP interface 46 shown in FIG. 18, when transmitting an image signal using the SDTI-CP network 50, a bit Streams can be transmitted in the form of an elementary stream (ES) that is easy to edit and suitable for short-distance transmission, and when transmitting image signals between remote studios using a public network such as ATM. , A bit stream can be transmitted in the form of a transport stream (TS) suitable for long-distance transmission.

In the above, the POI is inserted into the elementary stream, but the TSMUX / DEMUX 61 and the MPE
When the distance of the G encoder 42 is short, FIG.
As shown in the figure, the POI is transmitted from the MPEG encoder 42 to the TS MUX /
You may make it supply directly to DEMUX61.

However, in this case, the SDTI-CP network 50 for transmitting the elementary stream
Other wiring processing is required.

As described above, the information held by the encoder is stored in the user data in the elementary stream (ES).
And output to the multiplexing device or the decoder, the information (Coding Pha
se (V-Phase and H-Phase), Field_ID, coding order DTS_co
unter and the display order PTS_counter) can be supplied to a multiplexing device and a decoder subsequent to the encoder.

Next, the syntax of the bit stream will be described with reference to FIGS.

FIG. 23 is a diagram showing the syntax of an MPEG video stream. MPEG encoder 42
An encoded elementary stream according to the syntax shown in FIG. 23 is generated. In the syntax described below, functions and conditional statements are represented by fine print, and data elements are represented by bold print. The data item is described by a mnemonic (Mnemonic) indicating its name, bit length, and its type and transmission order.

First, functions used in the syntax shown in FIG. 23 will be described. In practice, the syntax shown in FIG.
This is a syntax used on the EG decoder 44 side to extract a predetermined meaningful data element from the transmitted encoded bit stream. MPE
The syntax used on the G encoder 42 side is based on the syntax shown in FIG.
This is a syntax that omits conditional statements such as statements.

The next_start_code () function described first in video_sequence () is a function for searching for a start code described in a bit stream. First, in the encoded stream generated according to the syntax shown in FIG. 23, sequence_hea
A data element defined by the der () function and the sequence_extension () function is described. This sequence
The _header () function is a function for defining the header data of the sequence layer of the MPEG bit stream,
The sequence_extension () function is a function for defining extension data of the sequence layer of the MPEG bit stream.

[0100] The do {} while syntax located next to the sequence_extension () function is data described based on the function in {} of the do statement while the condition defined by the while statement is true. This is a syntax indicating that the element is described in the encoded data stream. The nextbits () function used in this while statement is a function for comparing a bit or a bit string described in a bit stream with a referenced data element. In the example of the syntax shown in FIG. 23, the nextbits () function compares the bit sequence in the bit stream with sequence_end_code indicating the end of the video sequence, and when the bit sequence in the bit stream does not match sequence_end_code. , The condition of this while statement becomes true. Therefore, d placed next to the sequence_extension () function
The o {} while syntax indicates that the data element defined by the function in the do statement is described in the encoded bitstream while the sequence_end_code indicating the end of the video sequence does not appear in the bitstream. .

In the coded bit stream, the sequence
Following each data element defined by the ce_extension () function, a data element defined by the extension_and_user_data (0) function is described. This extension_and_user_data
The (0) function is a function for defining extension data and user data in the sequence layer of the MPEG bit stream.

The do {} while syntax located next to the extension_and_user_data (0) function is described based on the function in the {} of the do statement while the condition defined by the while statement is true. This is a function indicating that the data element is described in the bit stream. This whil
The nextbits () function used in the e-statement is a
A function for judging a match with start_code or group_start_code, which consists of bits or bit strings appearing in a bit stream, picture_start_code or group_star
If t_code matches, the condition defined by the while statement is true. Therefore, this do {} while syntax is
In the coded bitstream, picture_start_co
When de or group_start_code appears, it indicates that the code of the data element defined by the function in the do statement is described after the start code.

The if statement described at the beginning of the do statement is
The condition indicates that the group_start_code appears in the encoded bit stream. If the condition by this if statement is true, this
Data elements defined by the group_of_picture_header () function and the extension_and_user_data (1) function are described in order after the group_start_code.

This group_of_picture_header () function is
A function for defining the header data of the GOP layer of the PEG encoded bit stream, and the extension_and_user_d
The ata (1) function is a function for defining extended data and user data of the GOP layer of the MPEG encoded bit stream.

Further, in this encoded bit stream, a group_of_picture_header () function and an extension
After the data element defined by the _and_user_data (1) function, the picture_header () function and the picture_header
A data element defined by the coding_extension () function is described. Of course, if the condition of the if statement described above is not true, group_of_picture_he
Since the data elements defined by the ader () function and the extension_and_user_data (1) function are not described, the picture_header follows the data element defined by the extension_and_user_data (0) function.
() Function, picture_coding_extension () function and extens
A data element defined by the ion_and_user_data (2) function is described.

The picture_header () function is a function for defining the header data of the picture layer of the MPEG coded bit stream.
The () function is a function for defining the first extension data of the picture layer of the MPEG encoded bit stream. ex
The tension_and_user_data (2) function is a function for defining extension data and user data of a picture layer of an MPEG encoded bit stream. This extension_and_
User data defined by the user_data (2) function is
This is data described in the picture layer and can be described for each picture.

[0107] In the coded bit stream, next to the user data of the picture layer, a data element defined by a picture_data () function is described. The picture_data () function is a function for describing data elements relating to the slice layer and the macroblock layer.

The while statement described next to the picture_data () function is a function for determining the condition of the next if statement while the condition defined by the while statement is true. Nextbit used in this while statement
The s () function converts the picture_sta
A function to determine whether rt_code or group_start_code is described.
When picture_start_code or group_start_code is described, the condition defined by this while statement is true.

The following if statement is included in the encoded bit stream.
If it is a conditional statement for determining whether sequence_end_code is described or not, and sequence_end_code is not described, the sequence_header () function and sequencen
This indicates that the data element defined by the e_extension () function is described. sequence_end
Since _code is a code indicating the end of the sequence of the encoded video stream, the data elements defined by the sequence_header () function and the sequence_extension () function are described in the encoded stream unless the encoded stream ends. ing.

This sequence_header () function and sequence_ex
The data element described by the tension () function is described at the beginning of the video stream sequence.
It is exactly the same as the data element described by the sequence_header () and sequence_extension () functions.
The reason for describing the same data in the stream in this way is that when the bit stream receiving apparatus starts receiving data in the middle of the data stream (for example, the bit stream corresponding to the picture layer), the data of the sequence layer is received. This is to prevent a situation in which the stream cannot be decoded and the stream cannot be decoded.

The last sequence_header () function and sequence
After the data element defined by the nce_extension () function, that is, at the end of the data stream, a 2-bit sequence_end_code indicating the end of the sequence
Is described.

The sequence_header () function, sequencec
e_extension () function, extension_and_user_data (0) function, group_of_picture_header () function, picture_heade
r () function, picture_coding_extension () function, and pic
The ture_data () function will be described in detail.

FIG. 24 is a diagram for explaining the syntax of the sequence_header () function. This sequence_hea
The data element defined by the der () function is seq
uence_header_code, horizontal_size_value, vertical
_size_value, aspect_ratio_information, frame_rate_
code, bit_rate_value, marker_bit, vbv_buffer_size_
value, constrained_parameter_flag, load_intra_quan
tizer_matrix, intra_quantizer_matrix [64], load_non
_intra_quantizer_matrix, and non_intra_quantizer
_matrix and so on.

[0114] sequence_header_code is data representing a start synchronization code of the sequence layer. horizont
al_size_value is the lower 12 pixels of the number of pixels in the horizontal direction of the image.
This is data consisting of bits. vertical_size_value
Is data consisting of lower 12 bits of the number of vertical lines of the image. aspect_ratio_information is data representing an aspect ratio (aspect ratio) or a display screen aspect ratio of a pixel. frame_rate_code is data representing a display cycle of an image. bit_rate_value is the lower 18 bits (4 bits) of the bit rate for limiting the amount of generated bits.
(Rounded up in 00bsp units). marker_bit
Is bit data inserted to prevent start code emulation. vbv_buffer_size_valu
e is the lower 10-bit data of the value that determines the size of the virtual buffer (video buffer verifier) for controlling the generated code amount. constrained_parameter_flag is data indicating that each parameter is within the limit. lo
ad_intra_quantizer_matrix is data indicating the presence of intra MB quantization matrix data. intra_
quantizer_matrix [64] is data indicating the value of the quantization matrix for intra MB. load_non_intra_quantiz
er_matrix is data indicating the existence of non-intra MB quantization matrix data. non_intra_quantizer_
matrix is data representing the value of the non-intra MB quantization matrix.

FIG. 25 is a diagram for describing the syntax of the sequence_extension () function. This sequence_ext
The data elements defined by the extension () function are extension_start_code, extension_start_code_ide
ntifier, profile_and_level_indication, progressive
_sequence, chroma_format, horizontal_size_extensio
n, vertical_size_extension, bit_rate_extension, vb
v_buffer_size_extension, low_delay, frame_rate_ext
data elements such as extension_n and frame_rate_extension_d.

The extension_start_code is data representing a start synchronization code of the extension data. ex
tension_start_code_identifier is data indicating which extension data is sent. profile_and_level_in
The dication is data for specifying the profile and level of the video data. progressive_sequence is
This is data indicating that the video data is a progressive scan. chroma_format is data for specifying a color difference format of video data. horizontal_size_ex
tension is horizontal_size_value in the sequence header
Is the upper two bits of data to be added to vertical_size_
extension is the vertical_size_value of the sequence header
Higher 2 bits of data to be added. bit_rate_extensi
on is upper 12 bits of data to be added to bit_rate_value of the sequence header. vbv_buffer_size_extensio
n is upper 8-bit data added to vbv_buffer_size_value of the sequence header. low_delay is data indicating that a B picture is not included. frame_rate_e
xtension_n is data for obtaining a frame rate in combination with frame_rate_code of the sequence header. frame_rate_extension_d is fr of the sequence header
This is data for obtaining the frame rate in combination with ame_rate_code.

FIG. 26 is a diagram for explaining the syntax of the extension_and_user_data (i) function. This exte
When “i” is other than 1, the nsion_and_user_data (i) function describes only the data element defined by the user_data () function without describing the data element defined by the extension_data () function. So, exte
The nsion_and_user_data (0) function describes only the data elements defined by the user_data () function.

First, the functions used in the syntax shown in FIG. 26 will be described. nextbi
The ts () function is a function for comparing a bit or a bit string appearing in a bit stream with a data element to be decoded next.

As shown in FIG. 27, the user_data () function includes user_data_start_code, V-phase () function, and H-phas
e () function, Time_code () function, Picture-order () function, Anc
illary_data () function, history_data () function, and user_
This is a function for describing the data element of data.

The user_data_start_code is a start code for indicating the start of the user data area of the picture layer of the MPEG bit stream. This user_dat
The if statement described after a_start_code is user_data
(i) When i of the function is "0", while described in the following
Execute the syntax. This while syntax is true unless 24-bit data composed of 23 "0" s and subsequent "1s" appears in the bit stream.

The 24-bit data consisting of the 23 "0" s and the following "1" is data added to the head of all the start codes. , The nextbits () function can find the position of each start code in the bit stream.

When the while syntax is true, the nextbits () function of the if statement described next detects the bit string (Data_ID) indicating the V-Phase, and then detects the bit string (Data_ID).
From the next bit of, it is known that the data element of the V-Phase indicated by the V-Phase () function is described. Next Else i
The nextbits () function of the f statement uses a bit string (Data
_ID), it is known that the H-Phase data element indicated by the H-Phase () function is described from the next bit of the bit string (Data_ID).

Here, as shown in FIG. 28, D-Phase D
ata_ID is a bit string representing “01”, and D of H-Phase
ata_ID is a bit string representing “02”.

V-Phase () described in bit stream
The syntax of the function will be described with reference to FIG. First, as described above, Data_ID is 8-bit data indicating that the data element of the bit string following the Data_ID is a V-Phase, and has the value “0” shown in FIG.
1 ". V-Phase is 16-bit data indicating the first line to be encoded in a frame of an image signal.

H-Phase () described in bit stream
The syntax of the function will be described with reference to FIG. First, as described above, Data_ID is 8-bit data indicating that the data element of the bit string following the Data_ID is H-Phase, and has the value “0” shown in FIG.
H "is 2". The H-Phase is
This is 8-bit data indicating the first sample to be encoded.

Returning to FIG. 27, the next Else if statement is
When i of the data (i) function is 2, while described in the following
Execute the syntax. Since the contents of the while syntax are the same as those described above, the description is omitted here.

When the while syntax is true, in the next if statement, the nextbits () function detects a bit string indicating Time code 1 or detects a bit string indicating Time code 2, and returns the Time_code from the next bit of the bit string. It is known that the data element of the time code indicated by the function () is described.

As shown in FIG. 28, Data_ID of Time code 1 is a bit string representing “03”, and data of Time code 1 is VITC (Vertical Interval) indicating a time code inserted in the vertical blanking period of an image. Tim Cod
e). As shown in FIG. 28, Data_ID of Time code 2 is a bit string representing “04”, and the data of Time code 2 is LTC (Longitudinal Time Cod) indicating the time code recorded on the time code track of the recording medium.
e).

Next, in the Else if statement, when the nextbits () function detects a bit string indicating a Picture Order, the picture element of the Picture Order indicated by the Picture_Order () function is described from the next bit of the bit string. Know. Where Data_ID of Picture_Order () function
Is a bit string representing "05" as shown in FIG.

Referring to FIG. 31, the syntax of the Picture_Order () function actually inserted into the elementary stream (ES) by the encoder will be described. First, as described above, Data_ID is 8-bit data indicating that data subsequent to Data_ID is POI data, and its value is “05”. DTS_presence is the coding order DTS_co
This is 1-bit data indicating the presence or absence of an unter. For example,
When DTS_counter = PTS_counter as in a B picture, only the display order PTS_counter exists, and DTS_presence
Is "0". Conversely, in the case of a P picture and an I picture, the coding order DTS_counter and the display order PTS_c
Since the ounters are not the same, both the display order PTS_counter and the encoding order DTS_counter exist, and the bit of DTS_presence is 1.

[0131] PTS_counter is 7-bit data indicating the display order, which counts up each time one field in the encoded frame is input to the encoder. The 7-bit data is modulo having a value from 0 to 127. After the if statement, the bit of DTS_presence is 1
, That is, for a P picture and an I picture, the DTS_counter counts up.

Marker_bits is inserted every 16 bits in order to prevent a start code emulation in which a bit string in which user data is described coincides with the start code described above by chance and has a high possibility of causing image unlocking. Bit.

[0133] DTS_counter is 7-bit data indicating the encoding order, in which the encoder counts up each time encoded image data for one field is encoded. The 7-bit data is modulo having a value from 0 to 127.

As described above, the display order PTS_counter
Are assigned in units of fields. For example, in the case where encoded image data is converted from a frame rate of 24 Hz to a frame rate of 30 Hz and encoded, it is necessary to perform numbering after performing a 3-2 pull-down process. .

Returning to FIG. 27, the following description
The content of the while syntax is the same as that described above, so
Here, the description is omitted. When the while syntax is true,
In the following if statement, the nextbits () function
Is detected, it is known that the data element of the Ancillary data indicated by the Ancillary_data () function is described from the next bit of the bit string. Ancill
The Data_ID of the ary_data () function is, as shown in FIG.
07 ″.

Ancillary which adds an identifier to this auxiliary data
The syntax of the ary data will be described with reference to FIG.
The Ancillary_data () function is transmitted as user data in the picture layer, and the data includes a field identifier (Field_ID),
Line number (Line_number) and supplementary data (ancil
lary data) is inserted.

Data_ID is anci in the user data area.
8-bit data indicating llary data,
The value is "07" as shown in FIG.

Field_ID is 2-bit data.
When the value of the ressive_sequence flag (FIG. 25) is “0”, a Field_ID is added to each field in the encoded frame. When “0” is set in the repeat_first_field, there are two fields in this encoded frame, and the Field_ID is “0” in the first field and “0” in the next field as shown in FIG. When “1” is set and “1” is set in repeat_first_field, there are three fields in this encoded frame, and as the Field_ID, “0” is set in the first field and subsequent fields are set. "1" and "2" are set in the fields.

Field_ID is a progressive_sequence flag
Is "1", it is added for each encoded frame. Field_ID includes repeat_first_field and Top_field_fi
When both “rst” are set to “0”, the encoded frame has one progressive frame.
When the value “0” is set, the value “1” is set in the repeat_first_field, and the value “0” is set in the Top_field_first, the encoded frames include two progressive frames, so the values “0”, “1” Is set and repeat_f
When “1” is set to both irst_field and Top_field_first, the encoded frame is composed of three progressiv
Since an e frame exists, values “0” to “2” are set.

Line_number is 14-bit data, in which auxiliary data in each frame is described.
Indicates the line number specified by ITU-R BT.656-3, SMPTE274M, SMPTE293M, SMPTE296M.

Ancillary_data_length is 16-bit data and indicates the data length of ancillary_data_payload. Ancillary_data_payload represents the contents of auxiliary data composed of 22-bit data.
When the value of Ancillary_data_length of _payload is larger than the value of j (initial value 0), the value j (Ancillary_data_length
Is incremented by 1 and described from the bit string of the value of j.

The following While syntax indicates the syntax for the bytealigned () function, and the next data is bytealig
Zero_b if not a ned () function (when While syntax is true)
Describe it (1-bit data "0").

Returning to FIG. 27, in the next Else if statement, when the nextbits () function detects a bit string indicating History data,
() Know that the data element of History data indicated by the function is described. History_data () function Da
As shown in FIG. 28, ta_ID is a bit string representing “08”, and data represented by Data_ID “08” represents History data including history information of the encoding parameter.

In the last if statement, the nextbits () function is
When a bit string indicating user data is detected, it is known from the next bit of the bit string that a data element of user_data indicated by the user_data () function is described.

The bit string by which the nextbits () function in FIG. 27 knows that each data element is described is described as Data_ID shown in FIG. However, use of “00” as Data_ID is prohibited. Data indicated by Data_ID “80” indicates a control flag, and data indicated by Data_ID “FF” indicates user data.

FIG. 33 is a view for explaining the syntax of the group_of_picture_header () function. This grou
The data elements defined by the p_of_picture_header () function are group_start_code, time_code, closed_
It consists of gop and broken_link.

[0147] group_start_code is data indicating the start synchronization code of the GOP layer. time_code is a time code indicating the time from the beginning of the sequence of the first picture of the GOP. closed_gop is flag data indicating that an image in a GOP can be reproduced independently from another GOP. broken
_link is flag data indicating that the first B picture in the GOP cannot be accurately reproduced for editing or the like.

The extension_and_user_data (1) function is ext
As in the case of the extension_and_user_data (0) function, user_data
This function describes only the data element defined by the () function.

Next, referring to FIGS. 34 and 36, a picture_headr () function for describing a data element relating to a picture layer of an encoded stream, picture_cod
The ing_extension () function and picture_data () will be described.

FIG. 34 is a view for explaining the syntax of the picture_headr () function. This picture_headr ()
The data element defined by the function is picture_
start_code, temporal_reference, picture_coding_typ
e, vbv_delay, full_pel_forward_vector, forward_f_c
ode, full_pel_backward_vector, backward_f_code, ex
tra_bit_picture and extra_information_picture.

[0151] Specifically, picture_start_code is data representing the start synchronization code of the picture layer. temp
oral_reference is a number indicating the display order of pictures,
This data is reset at the beginning of P. picture_codin
g_type is data indicating a picture type.

Vbv_delay is data indicating the initial state of the VBV buffer, and is set for each picture. The picture of the coded elementary stream transmitted from the transmitting side system to the receiving side system is buffered in a VBV buffer provided in the receiving side system, and DTS
(Decoding Time Stamp)
It is drawn (read) from this VBV buffer and supplied to the decoder. The time defined by vbv_delay means the time from when the picture to be decoded starts to be buffered in the VBV buffer until the picture to be coded is extracted from the VBV buffer, that is, the time specified by DTS. I do. By using vbv_delay stored in this picture header, V
Seamless splicing can be realized in which the data occupancy of the BV buffer does not become discontinuous.

[0153] full_pel_forward_vector is data indicating whether the accuracy of the forward motion vector is an integer unit or a half pixel unit. forward_f_code is data representing a forward motion vector search range. full_pel_backward_vector is
This data indicates whether the accuracy of the backward motion vector is an integer unit or a half pixel unit. backward_f_code is data representing a backward motion vector search range. extra_bit_pictur
e is a flag indicating the presence of the following additional information. If this extra_bit_picture is "1", then extra_i
If nformation_picture exists and extra_bit_picture is “0”, it indicates that there is no data following it. extra_information_picture is information reserved in the standard.

FIG. 35 is a diagram for describing the syntax of the picture_coding_extension () function. This pict
The data elements defined by the ure_coding_extension () function are extension_start_code, extension_star
t_code_identifier, f_code [0] [0], f_code [0] [1], f_c
ode [1] [0], f_code [1] [1], intra_dc_precision, pictu
re_structure, top_field_first, frame_predictive_fr
ame_dct, concealment_motion_vectors, q_scale_typ
e, intra_vlc_format, alternate_scan, repeat_first_
field, chroma_420_type, progressive_frame, composi
te_display_flag, v_axis, field_sequence, sub_carri
er, burst_amplitude, and sub_carrier_phase.

[0155] extension_start_code is a start code indicating the start of extension data of the picture layer. extension_start_code_identifier is a code indicating which extension data is sent. f_code [0]
[0] is data representing the horizontal motion vector search range in the forward direction. f_code [0] [1] is data representing a vertical motion vector search range in the forward direction. f_code
[1] and [0] are data representing the horizontal motion vector search range in the backward direction. f_code [1] [1] is data representing the vertical motion vector search range in the backward direction.
intra_dc_precision is data representing the accuracy of the DC coefficient. picture_structure is data indicating a frame structure or a field structure. this is,
In the case of a field structure, the upper field or the lower field is also indicated.

In the case of a frame structure, top_field_first is a flag indicating whether the first field is a top field or a bottom field. In the case of a frame structure, frame_predictive_frame_dct is data indicating that the prediction of the frame mode DCT is only the frame mode. concealm
ent_motion_vectors is data indicating that a motion vector for concealing a transmission error is attached to an intra macroblock. q_scale_type is data indicating whether to use a linear quantization scale or a non-linear quantization scale. intra_vlc_format is data indicating whether another two-dimensional VLC (variable length code) is used for an intra macroblock. “alternate_scan” is data representing a choice between using a zigzag scan or an alternate scan.

Repeat_first_field is a flag indicating whether or not to generate a repeat field at the time of decoding.
In the decoding process, if repeat_first_field is “1”, a repeat field is generated and repeat
When _first_field is “0”, a process is performed in which a repeat field is not generated.

Chroma_420_type has the same value as the following progressive_frame when the signal format is 4: 2: 0,
Otherwise, it is data representing 0. progressive_
The frame is data indicating whether the picture has been sequentially scanned. composite_display_flag is data indicating whether the source signal is a composite signal. v_axis is data used when the source signal is PAL. field_sequence is data used when the source signal is PAL. sub_carrier
Is data used when the source signal is PAL. burst_amplitude is data used when the source signal is PAL. sub_carrier_phase is data used when the source signal is PAL.

FIG. 36 is a diagram for explaining the syntax of the picture_data () function. The data element defined by the picture_data () function is a data element defined by the slice () function. However,
If slice_start_code indicating the start code of the slice () function does not exist in the bit stream,
The data elements defined by the ice () function are not described in the bitstream.

[0160] The slice () function is a function for describing a data element relating to a slice layer. Specifically, the slice () function is slice_start_code, slice_quantiser_scale_co.
de, intra_slice_flag, intra_slice, reserved_bits,
extra_bit_slice, extra_information_slice, and ex
data elements such as tra_bit_slice and macroblock ()
A function for describing a data element defined by a function.

[0161] slice_start_code is a start code indicating the start of a data element defined by the slice () function. slice_quantiser_scale_code is data indicating a quantization step size set for a macroblock existing in this slice layer. However, when quantizer_scale_code is set for each macroblock, the macroblock_quantiser_scale_code data set for each macroblock is used with priority. intra_slice_flag is a flag indicating whether intra_slice and reserved_bits are present in the bit stream. intra_slice is data indicating whether or not a non-intra macroblock exists in the slice layer. When any of the macroblocks in the slice layer is a non-intra macroblock, intra_slice is “0”, and when all of the macroblocks in the slice layer are non-intra macroblocks, intra_slice is “1”. Become. reserved_bits is 7-bit data and takes a value of “0”. extra_bit_slice is a flag indicating that additional information exists as a coded stream, and is set to “1” when extra_information_slice exists next. If there is no additional information, it is set to “0”.

The macroblock () function is a function for describing a data element relating to a macroblock layer, and specifically, macroblock_escape, macroblock_ad
dress_increment, and macroblock_quantiser_scale_
This is a function for describing a data element such as code, and a data element defined by a macroblock_modes () function and a macroblock_vecters (s) function.

Macroblock_escape is a fixed bit string indicating whether or not the horizontal difference between the reference macroblock and the previous macroblock is 34 or more. If the horizontal difference between the reference macroblock and the previous macroblock is 34 or more, the macroblock_address_increment value is set to 33.
Plus macroblock_address_increment is data indicating a horizontal difference between the reference macroblock and the previous macroblock. If this macroblock_address_i
If there is one macroblock_escape before ncrement, the value of this macroblock_address_increment is 33
Is the data indicating the horizontal difference between the actual reference macroblock and the previous macroblock.
macroblock_quantiser_scale_code is a quantization step size set for each macroblock. In each slice layer, slice_quantiser_scale_code indicating the quantization step size of the slice layer is set, but the macroblock_quantiser
If _scale_code is set, this quantization step size is selected.

FIG. 37 is an explanatory diagram showing the data structure of an MPEG encoded stream. As shown in this figure, the data structure of the video elementary stream includes at least a sequence layer, a GOP layer, and a picture layer.

The sequence layer is next_start_code ()
Function 201, sequence_header () function 202, extension
_start_code () 203, sequence_extension () function 20
4. It is composed of data elements defined by the extension_and_user_data (0) function 205. GOP layer is group_start_code206, group_of_picture_h
It is composed of data elements defined by an eader () function 207 and an extension_and_user_data (1) function 208. The picture layer is a picture_header () function 2
09, picture_coding_extension () function 210, extens
It includes data elements defined by an ion_and_user_data (2) function 211 and a picture_data () function 212. At the end of the video sequence, sequence_end_code
213 are described.

Extension_and_user_data (2) function 211
Are user_data_start_code 214 and user_d, as can be understood from the syntax already described in FIG.
It contains data elements defined by the ata () function 215 and next_start_code 216.

As can be understood from the syntax already described in FIG. 27, the user_data () function 215
It contains data elements defined by the time_code () function 217 and user_data 218.

In this specification, the system is defined as
It is assumed that the device as a whole is constituted by a plurality of devices.

[0169] In the present specification, a providing medium for providing a user with a computer program for executing the above processing includes an information recording medium such as a magnetic disk and a CD-ROM, and a network such as the Internet and a digital satellite. Transmission media is also included.

[0170]

As described above, according to the digital signal transmission device according to the first aspect, the digital signal transmission method according to the fourth aspect, and the providing medium according to the fifth aspect, encoding of an image signal is performed. Since the range information indicating the range is inserted into the bit stream, the bit stream coded by a plurality of different methods can be correctly decoded by the digital signal receiving apparatus subsequent to the digital signal transmitting apparatus. Can be transmitted.

The digital signal receiving device according to claim 6,
According to the digital signal receiving method described in claim 7 and the providing medium described in claim 8, since the range information inserted in the bit stream is interpreted, the digital signal is encoded by a plurality of different methods. The bit stream can be decoded with the correct phase.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a coding phase.

FIG. 2 is a diagram illustrating auxiliary data.

FIG. 3 is a diagram showing a configuration of a system for transmitting an elementary stream.

FIG. 4 is a diagram showing a configuration of a system for transmitting auxiliary data.

FIG. 5 is a diagram illustrating a prediction structure and an encoding structure in the MPEG system.

FIG. 6 is a diagram illustrating a delay that occurs in an MPEG encoder.

FIG. 7 is a block diagram showing a configuration inside a studio.

FIG. 8 is a diagram for explaining data transmitted inside the studio of FIG. 7;

FIG. 9 is a diagram showing a configuration of a system for transmitting data in the system of FIG. 7;

FIG. 10 is a diagram illustrating auxiliary data of an image that has been subjected to 3-2 pull-down processing.

FIG. 11 is a block diagram illustrating a system configuration when a bit stream is transmitted between two studios.

FIG. 12 is a diagram illustrating a configuration of a stream transmitted by the system of FIG. 11;

FIG. 13 is a block diagram showing a configuration for transmitting a transport stream in the system of FIG.

FIG. 14 is a diagram illustrating a delay in an encoding process.

FIG. 15 is a block diagram illustrating a configuration of an MPEG encoder to which the present invention has been applied.

FIG. 16 is a block diagram illustrating a configuration of an MPEG decoder to which the present invention has been applied.

FIG. 17 is a diagram illustrating a configuration of a system when transmitting a CPI.

FIG. 18 is a block diagram illustrating a configuration of an SDTI-CP interface 46 in FIG.

FIG. 19 is a diagram illustrating transmission of auxiliary data.

[FIG. 20] PTS_counter in 3-2 pull-down processing
FIG. 3 is a diagram for explaining DTS_counter.

FIG. 21 is a diagram illustrating a configuration of a system when transmitting a POI.

FIG. 22 is a diagram illustrating a configuration of another system when transmitting a POI.

FIG. 23 is a diagram illustrating the syntax of a video_sequence function.

FIG. 24 is a diagram illustrating the syntax of a sequence_header () function.

FIG. 25 is a diagram for describing the syntax of the sequence_extension () function.

FIG. 26 is a diagram illustrating the syntax of an extension_and_user_data (i) function.

FIG. 27 is a diagram illustrating the syntax of a user data () function.

FIG. 28 is a diagram illustrating Data_ID of a function described in user data.

FIG. 29 is a diagram illustrating the syntax of a V-Phase () function.

FIG. 30 is a diagram illustrating the syntax of the H-Phase () function.

FIG. 31 is a diagram for describing the syntax of the Picture_Order () function.

[Fig. 32] Fig. 32 is a diagram for describing the syntax of the Ancillary_data () function.

FIG. 33 is a diagram illustrating the syntax of a group_of_picture_header () function.

Fig. 34 is a diagram for describing the syntax of the picture_header () function.

FIG. 35 is a diagram for describing the syntax of the picture_coding_extension () function.

FIG. 36 is a diagram for describing the syntax of the picture_data () function.

[Fig. 37] Fig. 37 is a diagram for describing layers of the MPEG system.

[Explanation of symbols]

42, 43 MPEG encoder, 44, 45 MPEG decoder, 46 to 49 SDTI-CP interface, 50
SDTI-CP network, 51 SDTI-CP interface, 61, 62 TS MUX / DEMUX, 72, 73 MPEG
Encoder, 74, 75 MPEG decoder, 76-8
1 SDTI-CP interface, 80 SDTI-CP network

Claims (8)

[Claims] 1. A digital signal transmission device that encodes an image signal corresponding to a predetermined image and transmits the encoded image signal as a bit stream, wherein an encoding unit that encodes the image signal in a predetermined range of the image. An insertion unit that inserts range information corresponding to the range encoded by the encoding unit into the bit stream, and a transmission unit that transmits the bit stream in which the range information is inserted by the insertion unit A digital signal transmission device characterized by the above-mentioned. 2. The digital signal transmission device according to claim 1, wherein the range information is information indicating an upper left position of a range to be coded in the image. 3. The digital signal transmission device according to claim 1, wherein the insertion unit inserts the range information into an elementary stream. 4. A digital signal transmission method of a digital signal transmission device for encoding an image signal corresponding to a predetermined image and transmitting the encoded image signal as a bit stream, wherein the image signal in a predetermined range of the image is encoded. An encoding step; an insertion step of inserting range information corresponding to the range encoded in the encoding step into the bit stream; and transmitting the bit stream in which the range information is inserted in the insertion step. Transmitting a digital signal. 5. An encoding step of encoding an image signal corresponding to a predetermined image and transmitting the image signal in a predetermined range of the image to a digital signal transmission device for transmitting the image signal as a bit stream; An insertion step of inserting range information corresponding to the range encoded in the encoding step into the bit stream; and a transmission step of transmitting the bit stream having the range information inserted in the insertion step. A providing medium for providing a computer-readable program for executing a process. 6. A digital signal receiving apparatus for encoding an image signal corresponding to a predetermined image and receiving a transmitted bit stream, wherein the image among the images inserted in the bit stream A digital signal, comprising: extracting means for extracting range information corresponding to a range for encoding a signal; and decoding means for decoding the bit stream based on the range information extracted by the extracting means. Receiver. 7. A digital signal receiving method for a digital signal receiving apparatus which receives a transmitted bit stream by encoding an image signal corresponding to a predetermined image, the digital signal receiving method comprising: An extracting step of extracting range information corresponding to a range in which the image signal is encoded; anda decoding step of decoding the bit stream based on the range information extracted in the extracting step. Characteristic digital signal receiving method. 8. A digital signal receiving apparatus that encodes an image signal corresponding to a predetermined image and receives a transmitted bitstream, wherein the image among the images inserted in the bitstream is A computer configured to execute a process including: an extraction step of extracting range information corresponding to a range in which a signal is to be encoded; and a decoding step of decoding the bit stream based on the range information extracted in the extraction step. A providing medium characterized by providing a possible program.