JP2003006984A - Signal processing apparatus and method - Google Patents

Abstract

(57) [Problem] To prevent lightness, saturation, hue, and the like of a reproduced image from greatly deviating from an original image even when a stream of QST = 0 is input to a device of QST = 1. SOLUTION: A QST checker 530A checks a QST in an input stream.
ST, QSC rewriting section 530B sets QST to “1”
And the QSC is rewritten. Q
The SC is rewritten by converting the QSC according to a predetermined rule so that the quantization scale of QST = 1 is approximated to the quantization scale of QST = 0. QST
= 0, the stream input is set to QST = 1, and QS
The QSC is converted and rewritten so that the quantization scale of T = 1 is approximated when QST = 0. QST =
When a stream of QST = 0 is input to a device fixed to 1, a significant shift in brightness, saturation, and hue of a reproduced image with respect to an original image can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to MPEG2 (Mov
2 kinds of quantizer_scal which are encoding parameters in ing Pictures Experts Group 2)
The present invention relates to a signal processing device and method adapted to approximately transform e_code.

[0002]

2. Description of the Related Art Digital VTR (Video Tape Recorde)
As represented by r), a digital video signal and a digital audio signal are recorded on a recording medium, and
A data recording / reproducing device for reproducing from a recording medium is known. Since a digital video signal has an enormous data capacity, it is generally compressed and encoded by a predetermined method and recorded on a recording medium. In recent years, MPEG2 (M
The oving Picture Experts Group 2) method is known as a standard method of compression coding.

In the image compression techniques such as the above-mentioned MPEG2, a variable length code is used to increase the data compression rate. Therefore, the code amount after compression of data for one screen, for example, one frame or one field varies depending on the complexity of the image to be compressed.

In the above-mentioned MPEG2 system, in a data having a hierarchical structure from the lower layer to the upper layer in the order of macroblock layer, slice layer, picture layer, GOP layer and sequence layer, the slice layer serves as a unit of variable length coding. There is. The macroblock layer further includes a plurality of DCT (D
iscrete Cosine Transform) block. A header portion in which header information is stored is provided at the beginning of each layer. For example, in the slice layer, the delimiter position of the variable length code is detected by detecting this header portion. The decoder for decoding the variable-length code decodes the variable-length code based on the detected delimiter position.

On the other hand, various image data formats are conceivable depending on the combination of the image size and the frame frequency and the difference in the scanning method. Video equipment for broadcasting and production generally imposes a predetermined restriction on the format of image data handled. MP mentioned above
The EG2 standard is designed to flexibly support such various image formats.

[0006]

By the way, in computer devices and data recorders, image information is treated as a simple data string. However, a general MPEG2-compatible video device cannot handle all image information that can be defined by MPEG2. For example, in a broadcasting or commercial device, the image size and the frame frequency are limited to the same values as those in the current broadcasting system, and the frame structure and the encoding type of the picture are fixed for the convenience of editing.

[0007] One of the encoding parameters fixedly handled by such a broadcasting or commercial device is qaun.
timer_scale_type (hereinafter, q_scale
le_type). The q_scale_type will be briefly described. In MPEG2 mentioned above,
Two types of curves, linear and non-linear, are prepared as the curves of the steps of the quantization scale (quantizer_scale). These two types of quantization scale are q
It is referred to using "auntizer_scale_code" as an index. q_scale_type is a parameter for selecting these two types of quantization scales. q_scale_type = 1 is the curve of the quantization scale step corresponding to the higher bit rate.

In a device for broadcasting or business use, this q_sc
The value of ale_type is often limited to “1” and handled. This means that a device limited to q_scale_type = 1 cannot handle a stream of q_scale_type = 0. q_scal
Mismatching e_type does not cause serious problems such as loss of synchronization, deviation of system delay, runaway or hang-up of the decoder.

However, q_scale_type
A stream encoded under the condition of = 0, q_sc
When decoding with ale_type = 1, there is a problem that the brightness, saturation, and hue of the reproduced image may greatly deviate from the original image.

For example, when encoding a graphic created by a computer with software,
There is a possibility that streams with different values of q_scale_type may be generated.

As a method of fetching a stream with q_scale_type = 0 into a system with q_scale_type = 1, q_scale_type = 0
Stream is decoded once, and again q_scale_
A method of encoding as a stream of type = 1 can be considered. However, this method has problems that it takes a lot of time and the circuit scale becomes large.

Therefore, the object of the present invention is q_sc.
The stream for which ale_type = 0 is q_sca
It is an object of the present invention to provide a signal processing device and method that prevent the brightness, saturation, hue, etc. of a reproduced image from being largely deviated from the original image even when input to a device with le_type = 1.

[0013]

In order to solve the above-mentioned problems, the present invention makes it possible to select and use a quantization scale for compression encoding from a plurality of sets of quantization scales. In a signal processing device to which a stream that has been compression-encoded by a compression-encoding method that refers to the encoding scale with a common index to a plurality of sets of quantization scales is input, compresses from the input stream that is compression-encoded. Detecting a parameter indicating a set of quantization scales used in encoding, determining means for determining whether the detected parameter indicates a predetermined set of quantization scales, and It has a rewriting unit that rewrites the parameter and also rewrites the index that refers to the quantization scale. If it is determined that the parameters in the stream indicate a group other than the predetermined group, the rewriting unit rewrites the parameters in the input stream to the parameters indicating the predetermined group and sets other than the predetermined group. In a signal processing device characterized in that the index that refers to the quantization scale in the input stream is rewritten with an index that approximately transforms the quantization scale of to a predetermined set of quantization scales. is there.

Further, according to the present invention, it is possible to select and use a quantization scale for compression encoding from a plurality of sets of quantization scales, and the quantization scale is an index common to the plurality of sets of quantization scales. In the signal processing method in which the stream coded by the compression coding method as referred to in is input, the set of quantization scales used in compression coding from the stream coded and input. Detecting the parameter, and determining whether the detected parameter indicates a predetermined set of quantization scales, and rewriting the parameters in the input stream and referring to the quantization scales. And a rewriting step of rewriting If it is determined that a set other than the predetermined set is indicated, in the rewriting step, the parameter in the input stream is rewritten to the parameter indicating the predetermined set, and the quantization scale of the set other than the predetermined set is set. The signal processing method is characterized in that an index that refers to a quantization scale in an input stream is rewritten with an index that approximately transforms into a predetermined set of quantization scales.

As described above, according to the present invention, a parameter indicating a set of quantization scales used at the time of compression encoding is detected from a stream encoded and input, and the detected parameter is quantized. If it is determined that the parameters in the input stream indicate a set other than the predetermined set, it is determined whether the parameters in the input stream are set to the predetermined set. In addition to rewriting the parameters shown, rewrite the index that refers to the quantization scale in the input stream with an index that approximately converts the quantization scale of a set other than the predetermined set to the quantization scale of the predetermined set. Therefore, even if a stream compressed and encoded using a quantum scale other than the predetermined set is input, the amount of the predetermined set is It can be approximately converted into compression-coded stream and outputs with scale.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The concept of the present invention will be described below with reference to FIGS. FIG. 1 shows a basic configuration of a digital VTR (Video Tape Recorder) that records and reproduces a baseband signal using a magnetic tape as a recording medium. At the time of recording, a baseband signal which is an uncompressed digital video signal is input from the terminal 500. The baseband signal is supplied to an ECC (Error Correction Coding) encoder 511 and is also supplied to an EE path 508 which is a monitor path of the input signal, and the switch circuit 50.
Input to 7. The baseband signal supplied to the ECC encoder 501 is subjected to shuffling and error correction coding processing, recorded and coded by the recording amplifier 502, supplied to a rotary head (not shown), and recorded on the magnetic tape 503 by the rotary head. It

At the time of reproduction, the reproduction signal reproduced by the rotary head from the magnetic tape 503 is supplied to the reproduction amplifier 504 and decoded into a digital signal. Reproduction amplifier 5
The output of 04 is supplied to the ECC decoder 505, and the error correction code is decoded and error-corrected and deshuffled. The baseband signal output from the ECC decoder 505 is input to the switch circuit 507. The switch circuit 507 selects one of the input baseband signal input from the EE path 508 and the baseband signal output from the ECC decoder 505, and the selected signal is led to the terminal 506.

FIG. 2 shows a basic structure of a digital VTR for recording and reproducing a stream in which a video signal is encoded by the MPEG2 system. At the time of recording, a baseband signal is input from the terminal 510 and supplied to the MPEG encoder 511. The MPEG encoder 511 encodes the supplied baseband signal in a predetermined MPEG2 system and outputs it as a stream. MPE
The stream output from the G encoder 511 is supplied to one input end of the selector 513. Also, MPE
The stream pre-encoded by the G2 method is the terminal 51.
Input from 2. This stream is a selector 513
Is supplied to the other input terminal of the.

The selector 513 selects a stream supplied to one input terminal and the other input terminal, and supplies it to the ECC encoder 514. Further, the output of the selector 513 is supplied to the EE path 523 which is a monitor path of the input signal and input to the switch circuit 522. The ECC encoder 514 performs predetermined shuffling and error correction coding processing on the stream, and the recording amplifier 515 records and codes the stream, which is supplied to a rotary head (not shown) and recorded on a magnetic tape 516.

At the time of reproduction, the reproduction signal reproduced from the magnetic tape 516 by the rotary head is supplied to the reproduction amplifier 517 and decoded into a digital signal. Reproduction amplifier 5
The output of 17 is supplied to the ECC decoder 518, the error correction code is decoded and the error is corrected, and the data is deshuffled to be an MPEG2 stream. E
The stream output from the CC decoder 518 is input to the switch circuit 522.

The switch circuit 522 selects one of the stream input from the EE path 523 and the stream output from the ECC decoder 518. The selected signal is directly output to the terminal 519. The stream selected by the switch circuit 522 is also supplied to the MPEG decoder 520. MPE
The stream supplied to the G decoder 520 is decoded into a baseband signal and is output to the terminal 521.

As described above, if the video signal can be transmitted as a stream between the devices, the same number of images can be transmitted with a smaller amount of information than the baseband signal. In addition, in contrast to the baseband connection that causes the deterioration of the image quality by repeatedly decompressing and compressing the data every transmission, the image information can be transmitted without the deterioration of the image quality by the stream connection. If the image is not processed, it can be said that the stream connection is more advantageous than the baseband connection.

FIG. 3 shows the basic structure of the VTR according to the present invention. In FIG. 3, parts corresponding to those in the above-described configuration of FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted. In FIG. 3, a QST conversion unit 530 is added to the configuration of FIG. The QST conversion unit 530 uses the QS
T checker 530A and QST, QSC rewriting unit 530
Have B.

The QST checker 530A allows MPEG
MP of the stream encoded and input in two formats
Quant, which is one of the encoding parameters of EG2
The sizer_scale_type (QST) is checked. Further, in the QST / QSC rewriting unit 530B, based on the check result of the QST checker 530A,
Q_scale_type of the input stream and qquantizer_scale_code (QS which is one of the encoding parameters of MPEG2)
Rewriting of C) is performed.

Here, the quantization scale (quantizer_scale) in MPEG2 will be briefly described. The quantization scale is a denominator at the time of quantization, and can be determined for each slice and each macroblock. In MPEG2, there are two types of quantization scale steps: a step in which the curve becomes linear and a step in which the curve becomes nonlinear. The non-linear step is more effective at high bit rates, ie when the quantization step size is small. The non-linear step quantization scale provides higher image quality than the linear step quantization scale.

The quantizer scale is qquantizer_
It is shown using scale_code as an index.
That is, the quantization scale and the quantizer_sc
There are two correspondences with ale_code,
Which of these is applied depends on q_scal
It is indicated by e_type. q_scale_ty
When pe is “0”, the linear quantization scale is shown, and when “1”, the nonlinear quantization scale is shown. qauntizer_
scale_code can be specified for each macroblock.

According to the present invention, the q_scale_type in the input stream is checked by the QST checker 530A, and if the check result shows that the value is "0", then Q_scale_type is checked.
In the ST / QSC rewriting unit 530B, the value of q_scale_type in the stream is rewritten to "1", and at the same time, qcounter_scale_code
Is rewritten with a value approximated so that the quantization scale becomes a value closest to the value when q_scale_type = 0.

As a result, even if the step of the quantization scale of the input stream is of a type that this VTR does not support, the brightness between the reproduced image and the original image,
It is possible to suppress the shift in saturation and hue.

In the configuration of FIG. 3, when the EE path 533 side is selected by the switch circuit 532, q_sca is applied to the encoded and input stream.
le_type is checked, and q_scale_type and qauntizer are checked based on the check result.
The stream in which _scale_code is rewritten can be directly led to the terminal 519. In this case, this VTR can be used as a quantum scale converter.

Next, an embodiment in which the present invention is applied to a digital VTR will be described. This digital VTR is suitable for use in a broadcasting environment,
Recording / recording video signals in different formats
It enables reproduction.

In the first embodiment, for example, the MPEG2 system is adopted as the compression system. MPEG2
Is a combination of motion compensation predictive coding and compression coding by DCT. The data structure of MPEG2 has a hierarchical structure. FIG. 4 shows a general MPEG.
2 schematically shows the hierarchical structure of two data streams. Figure 4
As shown in FIG. 3, the data structure is, from the bottom, a macroblock layer (FIG. 4E), a slice layer (FIG. 4D), a picture layer (FIG. 4C), a GOP layer (FIG. 4B) and a sequence layer (FIG. 4A). ing.

As shown in FIG. 4E, the macroblock layer is composed of DCT blocks, which are units for performing DCT. The macroblock layer is composed of a macroblock header and a plurality of DCT blocks. The slice layer is shown in Figure 4.
As shown in D, it is composed of a slice header part and one or more macroblocks. As shown in FIG. 4C, the picture layer is composed of a picture header section and one or more slices. A picture corresponds to one screen.
As shown in FIG. 4B, the GOP layer includes a GOP header portion, an I picture that is a picture based on intra-frame coding, and P and B pictures that are pictures based on predictive coding.

An I-picture (Intra-coded picture) uses information closed in only one picture when it is coded. Therefore, at the time of decoding, only the information of the I picture itself can be used for decoding. A P-picture (Predictive-coded picture) uses a previously decoded I-picture or P-picture that is temporally previous as a predictive picture (picture that serves as a reference for taking a difference). . Whether to code the difference from the motion-compensated predicted image, or to code without taking the difference,
Select the most efficient one in macroblock units. A B picture (Bidirectionally predictive-coded picture) is a previously decoded I picture or P picture that is temporally preceding, and a temporally posterior picture that is a temporally posterior picture. Three types of I-pictures or P-pictures already decoded as well as interpolated pictures made from both are used. Of the three types of differential encoding after motion compensation and intra encoding, the most efficient one is selected in macroblock units.

Therefore, as the macro block type,
Intra-frame coding (Intra) macroblocks, forward predicting the future from the past (Forward) inter-frame prediction macroblocks, and backward predicting the past from the future (Backward)
There are inter-frame prediction macroblocks and bidirectional macroblocks predicted from both front and back directions. All macroblocks in an I picture are intra-frame coded macroblocks. In addition, an intra-frame encoded macroblock and a forward inter-frame prediction macroblock are included in the P picture. B-pictures include all four types of macroblocks described above.

A GOP contains at least one I picture, and P and B pictures are allowed even if they do not exist. As shown in FIG. 4A, the uppermost sequence layer is composed of a sequence header part and a plurality of GOPs.

In the MPEG format, a slice is a variable length code sequence. The variable-length code sequence is a sequence in which a data boundary cannot be detected unless the variable-length code is correctly decoded.

At the beginning of the sequence layer, GOP layer, picture layer and slice layer, a start code having a predetermined bit pattern arranged in byte units is arranged. This start code arranged at the beginning of each layer is called a sequence header code in the sequence layer and a start code in the other layers, and the bit pattern is [00 00 01 xx] (hexadecimal notation). Two digits are shown, and [xx] indicates that different bit patterns are arranged in each layer.

That is, the start code and the sequence header code consist of 4 bytes (= 32 bits), and the type of information that follows can be identified based on the value of the 4th byte. Since these start code and sequence header code are aligned in byte units, they can be captured only by performing 4-byte pattern matching.

Further, the upper 4 bits of 1 byte following the start code serve as an identifier of the contents of the extended data area described later. The content of the extended data can be determined by the value of this identifier.

It should be noted that such an identification code having a predetermined bit pattern aligned in byte units is not arranged in the macro block layer and the DCT block in the macro block.

The header section of each layer will be described in more detail. In the sequence layer shown in FIG. 4A, the sequence header 2 is arranged at the beginning, and subsequently the sequence extension 3, the extension and the user data 4 are arranged. Sequence header 2
A sequence header code 1 is placed at the beginning of the. Although not shown, a predetermined start code is also placed at the beginning of each of the sequence extension 3 and the user data 4. The sequence header 2 to the extension and user data 4 are used as the header portion of the sequence layer.

In the sequence header 2, as shown in FIG. 5, the contents of each parameter and the allocated bits, the sequence header code 1, the encoded image size consisting of the number of pixels in the horizontal direction and the number of lines in the vertical direction, the aspect ratio, and the frame. Bit rate, VBV (Video Buffering Verif)
ier) Information set in sequence units, such as a buffer size and a quantization matrix, is stored by allocating a predetermined number of bits.

In FIG. 5 and each of FIGS. 15 to 15 which will be described later, some parameters are omitted in order to avoid complexity.

In the sequence extension 3 after the extension start code following the sequence header, as shown in FIG.
Additional data such as profile, level, color difference format, and progressive sequence used in MPEG2 are designated. As shown in FIG. 7, the extension and user data 4 can store the information of the RGB conversion characteristics of the original signal and the display image size by the sequence display (), and the scalability and the scalability of the scalability mode and the scalability by the sequence scalable extension (). You can specify layers.

Following the header of the sequence layer, GOP
Are arranged. At the beginning of the GOP, as shown in FIG. 4B, a GOP header 6 and user data 7 are arranged.
The GOP header 6 and the user data 7 are used as the header part of the GOP. As shown in FIG. 8, the GOP header 6 includes a GOP start code 5, a time code, and a GOP.
Flags indicating independence and legitimacy of are assigned a predetermined number of bits and stored. The user data 7 includes extension data and user data, as shown in FIG. Although not shown, a predetermined start code is placed at the beginning of each of the extension data and the user data.

A picture is arranged following the header part of the GOP layer. As shown in FIG. 4C, a picture header 9, a picture coding extension 10, and extension and user data 11 are arranged at the head of the picture. A picture start code 8 is arranged at the head of the picture header 9. A predetermined start code is arranged at the beginning of each of the picture coding extension 10 and the extension and user data 11. The picture header 9 to the extension and user data 11 are the header part of the picture.

As shown in FIG. 10, the picture header 9 is provided with a picture start code 8 and is set with a coding condition for the screen. In the picture coding extension 10, as shown in FIG. 11, the range of the motion vector in the front-back direction and the horizontal / vertical direction and the picture structure are specified. Also, picture coding extension 1
At 0, the DC coefficient precision of the intra macroblock is set, the VLC type is selected, the linear / non-linear quantization scale is selected, and the scanning method in the DCT is selected.

In the extension and user data 11, FIG.
As shown in, the quantization matrix setting, the spatial scalable parameter setting, and the like are performed. These settings are possible for each picture, and encoding can be performed according to the characteristics of each screen. In the extension and user data 11, it is possible to set the display area of the picture. Further, copyright information can be set in the extension and user data 11.

Slices are arranged following the header part of the picture layer. As shown in FIG. 4D, the slice header 13 is arranged at the head of the slice, and the slice head 1
A slice start code 12 is placed at the beginning of the number 3.
As shown in FIG. 13, slice start code 12
Includes vertical position information of the slice. The slice header 13 further stores extended slice vertical position information, quantization scale information, and the like.

Macroblocks are arranged following the header portion of the slice layer (FIG. 4E). In the macroblock, a plurality of DCT blocks are arranged following the macroblock header 14. As mentioned above, macroblock header 1
No start code is assigned to 4. As shown in FIG. 14, the macroblock header 14 stores relative position information of macroblocks, and instructs the setting of the motion compensation mode, the detailed setting regarding DCT coding, and the like.

Following the macroblock header 14, DC
T blocks are arranged. The DCT block includes variable length coded DCT coefficients and D as shown in FIG.
Data regarding the CT coefficient is stored.

In FIG. 4, solid line delimiters in each layer indicate that data is aligned in byte units, and dotted line delimiters indicate that data is not aligned in byte units. That is, up to the picture layer, as shown in FIG.
As shown in an example in FIG. 6A, the boundaries of the code are divided in byte units, whereas in the slice layer, only the slice start code 12 is divided in byte units, and each macroblock is shown in FIG. 16B. As shown in the example, the data can be divided bit by bit. Similarly, in the macroblock layer, each DCT block can be divided in bit units.

On the other hand, in order to avoid signal deterioration due to decoding and coding, it is desirable to edit the coded data. At this time, the P picture and the B picture require temporally previous pictures or temporally previous and subsequent pictures for decoding. Therefore, the editing unit cannot be one frame. In consideration of this point, in the first embodiment, one GOP is made up of one I picture.

Further, for example, the recording area in which the recording data for one frame is recorded is set to a predetermined one. MPEG2
Since variable length coding is used, the amount of generated data for one frame is controlled so that the data generated in one frame period can be recorded in a predetermined recording area. Further, in the first embodiment, one slice is made up of one macroblock and one macroblock is applied to a fixed frame having a predetermined length so as to be suitable for recording on a magnetic tape.

FIG. 17 shows the M according to the first embodiment.
The header of the PEG stream is specifically shown. As can be seen from FIG. 4, the header parts of the sequence layer, GOP layer, picture layer, slice layer, and macroblock layer continuously appear from the beginning of the sequence layer. FIG. 17
Indicates an example data array that is continuous from the sequence header portion.

A sequence header 2 having a length of 12 bytes is arranged from the beginning, and a sequence extension 3 having a length of 10 bytes is arranged subsequently. Next to the sequence extension 3, extension and user data 4 are arranged.
A 4-byte user data start code is placed at the beginning of the extension and user data 4, and information based on the SMPTE standard is stored in the subsequent user data area.

The header portion of the sequence layer is followed by the header portion of the GOP layer. A GOP header 6 having a length of 8 bytes is arranged, followed by extension and user data 7. A 4-byte user data start code is placed at the beginning of the extension and user data 7, and the following user data area stores information for compatibility with other existing video formats.

The header of the GOP layer is followed by the header of the picture layer. A picture header 9 having a length of 9 bytes is arranged, followed by a picture coding extension 10 having a length of 9 bytes. After the picture coding extension 10, extension and user data 11 are arranged. Expansion and user data are stored in the leading 133 bytes of the expansion and user data 11, and subsequently, a user data start code 15 having a length of 4 bytes is arranged. Following the user data start code 15, information for compatibility with other existing video formats is stored. Further, a user data start code 16 is provided, and following the user data start code 16, SMP
Data based on the TE standard is stored. Next to the header part of the picture layer is a slice.

The macroblock will be described in more detail. The macroblock included in the slice layer is a set of a plurality of DCT blocks, and the encoded sequence of the DCT block is a sequence of quantized DCT coefficients, the number of consecutive 0 coefficients (run) and a non-zero sequence immediately after that. This is a variable-length code in which (level) is one unit. For macroblocks and DCT blocks within macroblocks,
The identification code arranged in byte units is not added.

The macroblock has a screen (picture) of 1
It is divided into a grid of 6 pixels × 16 lines. The slice is formed by connecting the macroblocks in the horizontal direction, for example. The last macroblock of a slice before a continuous slice and the first macroblock of the next slice are continuous, and it is not allowed to form a macroblock overlap between slices. Further, when the screen size is determined, the number of macroblocks per screen is uniquely determined.

The numbers of macroblocks in the vertical and horizontal directions on the screen are set to mb_height and m, respectively.
It is called b_width. The coordinates of the macroblock on the screen are mb_row, which is the vertical position number of the macroblock, which is counted from 0 based on the upper end, and mb_colu, which is the horizontal position number of the macroblock, which is counted from 0 based on the left end.
mn and mn. In order to represent the position of the macro block on the screen with one variable, macro
block_address to macroblock
_Address = mb_row × mb_width +
mb_column Defined like this.

It is specified that the order of slices and macroblocks on the stream must be in the order of smaller macroblock_address. That is, the stream is transmitted from the top to the bottom of the screen and from the left to the right.

In MPEG, one slice is usually composed of one stripe (16 lines), and variable length coding starts from the left end of the screen and ends at the right end. Therefore, V
When the MPEG elementary stream is recorded as it is by TR, the reproducible portion is concentrated on the left end of the screen during high-speed reproduction, and it cannot be uniformly updated. Further, since the arrangement of the data on the tape cannot be predicted, even if the tape pattern is traced at regular intervals, the uniform screen update cannot be performed. Furthermore, if an error occurs even at one location, it affects the right edge of the screen and cannot recover until the next slice header is detected. For this reason, one slice is made up of one macroblock.

FIG. 18 shows an example of the structure of the recording / reproducing apparatus according to the first embodiment. When recording, terminal 10
The digital signal input from 0 is SDI (Serial Data
Interface) is supplied to the receiving unit 101. SDI is
In order to transmit a (4: 2: 2) component video signal, a digital audio signal and additional data, S
This is an interface defined by MPTE.
The SDI receiving unit 101 extracts a digital video signal and a digital audio signal from the input digital signal, supplies the digital video signal (baseband signal) to the MPEG encoder 102, and the digital audio signal passes through the delay 103. Through E
It is supplied to the CC encoder 109. Delay 103
Is for eliminating the time difference between the digital audio signal and the digital video signal.

The output of the SDI receiver 101 is further E
It is also supplied to the switch circuit 550 via the E path. When the EE path side is selected in the switch circuit 550,
The digital video signal output from the SDI receiving unit 101 is supplied from the EE path to the SDI output unit 118, which will be described later, via the switch circuit 550 and is led to the output terminal 120.

The SDI receiving section 101 extracts a sync signal from the input digital signal and supplies the extracted sync signal to the timing generator 104. An external synchronization signal can be input to the timing generator 104 from the terminal 105. The timing generator 104 generates a timing pulse on the basis of a designated signal among these input synchronizing signals and the synchronizing signal supplied from the SDTI receiving unit 108 described later. The generated timing pulse is supplied to each part of this recording / reproducing apparatus.

The input video signal is the MPEG encoder 1
In 02, a DCT (Discrete Cosine Transform) process is performed, the coefficient data is converted, and the coefficient data is variable-length coded. The variable length coded (VLC) data from the MPEG encoder 102 is an elementary stream (ES) compliant with MPEG2. This output is supplied to one input end of a recording-side multi-format converter (hereinafter referred to as MFC) 106.

On the other hand, through the input terminal 107, SDTI
Data in the (Serial Data Transport Interface) format is input. This signal is sent to the SDTI receiver 10
8, the synchronization is detected. Then, it is temporarily stored in the buffer and the elementary stream is extracted. The extracted elementary stream is supplied to the QST conversion unit 530, q_scale_type is checked as described above, and q_scale is checked based on the check result.
_Type and qauntizer_scale_c
The ode is rewritten. The MPEG ES output from the QST conversion unit 530 is supplied to the other input end of the recording MFC 106. The synchronization signal obtained by the synchronization detection is supplied to the timing generator 104 described above.

The MPEG ES output from the QST converter 530 is sent to the switch circuit 55 via the EE path.
1 is also supplied to one input terminal.

In the present invention, for example, MPEG ES (M
In order to transmit a PEG elementary stream)
DTI (Serial Data Transport Interface) -CP (Con
tentPackage) is used. This ES is 4: 2: 2
In addition, as described above, all are I-picture streams and have a relationship of 1 GOP = 1 picture. In SDTI-CP format,
MPEG ES is separated into access units, and
It is packed in packets in frame units. SD
In TI-CP, a sufficient transmission band (2 at the clock rate
7MHz or 36MHz, 27 at stream bit rate
0 M bps or 360 M bps) is used, and ES can be sent in a burst in one frame period.

That is, the system data, the video stream, the audio stream, and the AUX data are arranged between SAV of one frame period and EAV.
The data does not exist in the entire one frame period, but the data exists in a burst form for a predetermined period from the beginning thereof. SDTI-CP streams (video and audio) can be switched in a stream state at frame boundaries. SDTI-CP has a mechanism for establishing synchronization between audio and video in the case of content using SMPTE time code as a clock reference. Furthermore, the format is determined so that SDTI-CP and SDI can coexist.

In the interface using SDTI-CP described above, the encoder and the decoder use VBV (Video B) as in the case of transferring TS (Transport Stream).
uffer Verifier) buffer and TBs (Transport Buf)
You don't have to go through the fers) and you can reduce the delay. Also, the fact that SDTI-CP itself can perform extremely high-speed transfer further reduces the delay. Therefore, in an environment where synchronization exists that manages the entire broadcasting station, SDTI-
It is effective to use CP.

The SDTI receiving section 108 further extracts a digital audio signal from the input SDTI-CP stream. The extracted digital audio signal is supplied to the ECC encoder 109.

The recording MFC 106 contains a selector and a stream converter. The above-mentioned QST conversion unit 530 can be incorporated in the recording MFC 106. The recording MFC 106 is configured in, for example, one integrated circuit. The processing performed in the recording MFC 106 will be described. MPEG encoder 102 described above
And MPEG supplied from the SDTI receiver 108.
One of ES is selected by the selector and supplied to the stream converter.

In the stream converter, the DCTs arranged in each DCT block based on the MPEG2 standard.
Coefficients are grouped for each frequency component through a plurality of DCT blocks forming one macroblock, and the grouped frequency components are rearranged. Further, the stream converter, when one slice of the elementary stream is one stripe, makes one slice consist of one macroblock. Furthermore, the stream converter limits the maximum length of variable length data generated in one macroblock to a predetermined length. This can be done by setting the high-order DCT coefficient to 0. The rearranged converted elementary stream is E
It is supplied to the CC encoder 109.

The ECC encoder 109 is connected to a large-capacity main memory (not shown), and has a packing and shuffling section, an audio outer code encoder, a video outer code encoder, an inner code encoder, an audio shuffling section, and a video. It has a built-in shuffling part. The ECC encoder 109 also includes a circuit that adds an ID in sync block units and a circuit that adds a synchronization signal. The ECC encoder 109 is composed of, for example, one integrated circuit.

In the first embodiment, a product code is used as the error correction code for video data and audio data. The product code is a code in which an outer code is encoded in the vertical direction of a two-dimensional array of video data or audio data, an inner code is encoded in the horizontal direction, and a data symbol is doubly encoded. Reed-Solomon code (Reed-Solo code)
mon code) can be used.

The processing in the ECC encoder 109 will be described. Since the video data of the elementary stream is variable-length coded, the data lengths of the macroblocks are not uniform. In the packing and shuffling section, macro blocks are packed in a fixed frame. At this time, the overflow portion protruding from the fixed frame is sequentially packed in an area vacant with respect to the size of the fixed frame.

Further, system data having information such as an image format and a shuffling pattern version is supplied from a system controller 121, which will be described later, and input from an input end (not shown). The system data is supplied to the packing and shuffling unit and subjected to the recording process like the picture data. Further, shuffling is performed to rearrange the macroblocks of one frame that occur in the scanning order and to distribute the recording positions of the macroblocks on the tape. The shuffling can improve the image update rate even when the data is fragmentarily reproduced during variable speed reproduction.

Video data and system data from the packing and shuffling section (hereinafter, simply referred to as video data when including system data unless otherwise required) are coded by outer coding. Is supplied to the outer code encoder for video, and the outer code parity is added. The output of the outer code encoder is shuffled by switching the order in sync block units over a plurality of ECC blocks in a video shuffling unit. Shuffling in sync block units prevents errors from concentrating on a specific ECC block. The shuffling performed by the shuffling section may be referred to as interleave. The output of the video shuffling unit is written in the main memory.

On the other hand, as described above, the SDTI receiver 1
08 or the digital audio signal output from the delay 103 is supplied to the ECC encoder 109. In the first mode of this embodiment, an uncompressed digital audio signal is handled. The digital audio signal is not limited to these, and may be input via an audio interface. An audio AUX is supplied from an input terminal (not shown). The audio AUX is auxiliary data, and is data having information related to the audio data such as a sampling frequency of the audio data. The audio AUX is added to the audio data and treated in the same manner as the audio data.

Audio data added with an audio AUX (hereinafter, simply referred to as audio data even when including AUX unless otherwise required) is an outer code for audio which performs outer code coding on the audio data. Supplied to the encoder. The output of the audio outer code encoder is supplied to the audio shuffling unit and subjected to shuffling processing. As audio shuffling, shuffling in sync block units and shuffling in channel units are performed.

The output of the audio shuffling section is written in the main memory. As described above, the output of the video shuffling unit is also written in the main memory, and the audio data and the video data are mixed in the main memory to form one-channel data.

Data is read from the main memory, an ID having information indicating a sync block number and the like is added, and the data is supplied to the inner code encoder. The inner code encoder encodes the supplied data with an inner code. A sync signal for each sync block is added to the output of the inner code encoder to form recording data in which sync blocks are continuous.

The recording data output from the ECC encoder 109 is supplied to the equalizer 110 including a recording amplifier and converted into a recording RF signal. The recording RF signal is supplied to the rotary drum 111 provided with a predetermined rotary head and recorded on the magnetic tape 112. A plurality of magnetic heads having different azimuths of heads forming adjacent tracks are actually attached to the rotary drum 111.

The recording data may be scrambled if necessary. Also, digital modulation may be performed during recording, and partial response class 4 and Viterbi code may be used. The equalizer 110 includes both a recording-side configuration and a reproduction-side configuration.

FIG. 19 shows an example of a track format formed on a magnetic tape by the above rotary head. In this example, video and audio data per frame is recorded in 4 tracks. One segment is composed of two tracks of different azimuths. That is, 4 tracks consist of 4 segments. Track number corresponding to azimuth for one set of tracks that make up a segment

[0] and track number [1] are added. In each of the tracks, video sectors on which video data is recorded are arranged on both ends,
An audio sector in which audio data is recorded is arranged between the video sectors. FIG. 19 shows the arrangement of sectors on the tape.

In this example, 4-channel audio data can be handled. A1 to A4
Indicates channels 1 to 4 of audio data, respectively. The audio data is recorded by changing the arrangement for each segment. In this example, the video data is interleaved with data for four error correction blocks for one track, and Upper Side and Lowe
It is recorded by being divided into r Side sectors.

The system sector (SY) in which system data is recorded is recorded in the video sector of Lower Side.
S) is provided at a predetermined position. The system area is alternately provided for each track on the leading side and the trailing side of the lower side video sector.

In FIG. 19, SAT is an area in which a signal for servo lock is recorded. Further, a gap having a predetermined size is provided between each recording area.

FIG. 19 shows that the data per frame is 4
Although an example of recording by tracks is used, data per frame can be recorded by 8 tracks, 6 tracks, etc. depending on the format of data to be recorded and reproduced.

As shown in FIG. 19B, the data recorded on the tape is composed of a plurality of blocks called sync blocks which are divided at equal intervals. FIG. 19C schematically shows the structure of a sync block. The sync block is
It is composed of a SYNC pattern for detecting synchronization, an ID for identifying each sync block, a DID indicating the content of subsequent data, a data packet and an inner code parity for error correction. Data is handled as a packet in sync block units. That is, the smallest data unit to be recorded or reproduced is one sync block. Many sync blocks are lined up (Fig. 1
9B), for example a video sector is formed.

FIG. 19D shows an example of the data structure of the system area SYS. In the data area in the sync block shown in FIG. 19C, 5 bytes are allocated to the system data, 2 bytes to the MPEG header, 10 bytes to the picture information, and 92 bytes to the user data from the beginning.

In the system data, the presence or absence of switching points and their positions, video formats (frame frequency, interleaving method, aspect ratio, etc.), shuffling version information, etc. are recorded. Further, in the system data, an appropriate level of the recorded MPEG ES syntax is recorded using 6 bits.

In the MPEG header, MPEG header information necessary for shuttle reproduction is recorded. Information for maintaining compatibility with other digital VTRs is recorded in the picture information. Further, the date of recording and the cassette number are recorded in the user data.

Returning to the explanation of FIG. 18, at the time of reproduction, the reproduction signal reproduced from the magnetic tape 112 on the rotary drum 111 is supplied to the reproduction side structure of the equalizer 110 including a reproduction amplifier and the like. The equalizer 110 performs equalization and waveform shaping on the reproduced signal. In addition, demodulation of digital modulation, Viterbi decoding and the like are performed as necessary.
The output of the equalizer 110 is supplied to the ECC decoder 113.

The ECC decoder 113 uses the ECC described above.
It performs a process reverse to that of the encoder 109, and includes a large-capacity main memory, an inner code decoder, audio and video deshuffling units, and an outer code decoder. Further, the ECC decoder 113 includes a deshuffling and depacking unit and a data interpolation unit for video. Similarly, for audio, an audio AUX separation unit and a data interpolation unit are included. The ECC decoder 113 is composed of, for example, one integrated circuit.

The processing in the ECC decoder 113 will be described. The ECC decoder 113 first performs synchronization detection, detects a synchronization signal added to the head of the sync block, and cuts out the sync block. The reproduced data is supplied to the inner code encoder for each sync block, and the inner code is error-corrected. ID interpolation processing is performed on the output of the inner code encoder, and the ID of the sync block that has been determined to be an error by the inner code, for example, the sync block number is interpolated. The reproduction data in which the ID is interpolated is separated into video data and audio data.

As described above, the video data is MPE
It means DCT coefficient data and system data generated by G intra-coding, and audio data is PCM.
(Pulse Code Modulation) Data and audio AU
Means X.

The separated audio data is supplied to the audio deshuffling section, and the processing opposite to the shuffling performed in the recording side shuffling section is performed. The output of the deshuffling unit is supplied to the outer code decoder for audio, and error correction is performed by the outer code. Error-corrected audio data is output from the audio outer code decoder. An error flag is set for data with uncorrectable errors.

The audio AUX separating unit separates the audio AUX from the output of the outer code decoder for audio, and the separated audio AUX is the ECC decoder 1
13 is output (the route is omitted). Audio A
The UX is supplied to, for example, the syscon 121 described later.
Also, the audio data is supplied to the data interpolation unit. The data interpolating unit interpolates a sample having an error. As the interpolation method, average value interpolation for interpolating with the average value of correct data before and after temporally, previous value hold for holding the value of the previous correct sample, and the like can be used.

The output of the data interpolation unit is the ECC decoder 11
Audio data output from the ECC decoder 113 is output to the delay 117 and the SDTI output unit 115. The delay 117 is provided to absorb a delay due to processing of video data by the MPEG decoder 116 described later. The audio data supplied to the delay 117 is given a predetermined delay and then supplied to the SDI output unit 118.

The separated video data is supplied to the deshuffling section and processed in the reverse of the shuffling on the recording side. The deshuffling unit restores the shuffling in sync block units performed by the shuffling unit on the recording side. The output of the deshuffling unit is supplied to the outer code decoder, and error correction is performed using the outer code. When an uncorrectable error occurs, an error flag indicating the presence / absence of an error indicates that there is an error.

The output of the outer code decoder is supplied to the deshuffling and depacking section. The deshuffling and depacking unit performs a process of returning the shuffling performed in the packing and shuffling units on the recording side in macroblock units. In the deshuffling and depacking section, the packing applied during recording is disassembled. That is, the length of data is returned in units of macroblocks to restore the original variable length code. Further, in the deshuffling and depacking unit, the system data is separated, output from the ECC decoder 113, and supplied to the syscon 121 described later.

The output of the deshuffling and depacking unit is supplied to the data interpolating unit, and the data having an error flag (that is, having an error) is corrected.
That is, if it is determined that there is an error in the middle of the macroblock data before conversion, the DCT coefficient of the frequency component after the error location cannot be restored. Therefore, for example, the data at the error location is replaced with a block end code (EOB), and the DCT coefficient of the frequency components thereafter is set to zero.
Similarly, even during high-speed reproduction, only the DCT coefficients up to the length corresponding to the sync block length are restored, and the coefficients after that are replaced with zero data. Further, the data interpolating unit also performs processing for recovering the header (sequence header, GOP header, picture header, user data, etc.) when the header added to the beginning of the video data is in error.

Since the DCT coefficients are arranged from the DC component and the low frequency component to the high frequency component across the DCT block, even if the DCT coefficient is ignored from a certain point onward, the macro block It is possible to evenly distribute DCT coefficients from DC and low-frequency components to each of the DCT blocks constituting the.

The video data output from the data interpolating unit is the output of the ECC decoder 113, and the output of the ECC decoder 113 is supplied to a multi-format converter on the reproducing side (hereinafter abbreviated as MFC on the reproducing side) 114. . The reproduction side MFC 114 is the recording side MFC 1 described above.
It performs the reverse processing of 06 and includes a stream converter. The reproducing MFC 114 is composed of, for example, one integrated circuit.

The stream converter performs the reverse process of the recording side stream converter. That is, D
The DCT coefficients that were arranged for each frequency component across the CT blocks are rearranged for each DCT block. As a result, the reproduction signal is converted into an MPEG2-compliant elementary stream.

The input / output of the stream converter is
Similar to the recording side, a sufficient transfer rate (bandwidth) is secured according to the maximum length of the macroblock. When the length of the macro block (slice) is not limited, it is preferable to secure a bandwidth that is three times the pixel rate.

The output of the stream converter is the reproduction side MF.
This is the output of C114. The output of the MFC 114 on the playback side is
It is supplied to the other input end of the switch circuit 551 that switches the path to the EE path side. The output of the switch circuit 551 is the output of the SDTI output unit 115 and the MPEG decoder 11.
6 is supplied.

The MPEG decoder 116 decodes the elementary stream and outputs video data. That is, the MPEG decoder 142 performs the inverse quantization process and the inverse D
CT processing is performed. The decoded video data is sent to the S through the switch circuit 550 that switches the path to the EE path side.
It is supplied to the DI output unit 118. As mentioned above, SD
The audio data separated from the video data by the ECC decoder 113 is supplied to the I output unit 118 via the delay 117. The SDI output unit 118 maps the supplied video data and audio data into an SDI format and converts the stream into a stream having a data structure of the SDI format. The stream from the SDI output unit 118 is output from the output terminal 120 to the outside.

On the other hand, the SDTI output section 115 is supplied with the audio data separated from the video data by the ECC decoder 113 as described above. The SDTI output unit 115 receives the SDT of the supplied video data as an elementary stream and audio data.
It is mapped to the I format and converted into a stream having a data structure of the SDTI format. The converted stream is output from the output terminal 119 to the outside.

In FIG. 18, the syscon 121 is composed of, for example, a microcomputer and controls the overall operation of this recording / reproducing apparatus. Further, when switches provided on a control panel (not shown) are operated, a control signal corresponding to the operation is supplied to the sys-con 121. Based on this control signal, the syscon 121 controls operations such as recording and reproducing in this recording / reproducing apparatus.

Further, the control panel has an LCD
A display unit such as (Liquid Crystal Display) can be provided (not shown). Based on the display control signal generated by the system controller 121, a predetermined display is displayed on the display unit. Each state of the recording / reproducing apparatus is displayed on the display unit.

The servo 122 controls the running of the magnetic tape 112 and the drive of the rotary drum 111 while communicating with the system controller 121.

FIG. 20A shows the order of DCT coefficients in the video data output from the DCT circuit of the MPEG encoder 102. M output from the SDTI receiving unit 108
The same applies to PEG ES. In the following, MPE
The output of the G encoder 102 will be described as an example. DC
Starting from the DC component at the upper left of the T block, DCT coefficients are output in a zigzag scan in the direction in which the horizontal and vertical spatial frequencies increase. As a result, FIG.
As shown in FIG. 1, a total of 64 (8 pixels × 8 lines) DCT coefficients are arranged in order of frequency components.

This DCT coefficient is the V of the MPEG encoder.
Variable length coding is performed by the LC unit. That is, the first coefficient is fixed as the DC component and the second component (AC
Component), a code is assigned corresponding to a run of zeros and subsequent levels. Therefore, the variable-length coded output for the coefficient data of the AC component is such that the coefficient of the frequency component is low (low order) to high (high order), AC ₁ ,
AC ₂ , AC ₃ , ... Are arranged. The elementary stream includes DCT coefficients that have been variable-length coded.

The recording-side stream converter built in the recording-side MFC 106 described above sorts the DCT coefficients of the supplied signals. That is, in each macroblock, the DCT coefficients arranged in the frequency component order in each DCT block by the zigzag scan are rearranged in the frequency component order in each DCT block forming the macroblock.

FIG. 21 schematically shows rearrangement of DCT coefficients in this recording side stream converter.
In the case of a (4: 2: 2) component signal, one macroblock includes four DCT blocks (Y ₁ , Y ₂ , Y ₃ and Y ₄ ) based on the luminance signal Y and chromaticity signals Cb and C.
Two DCT blocks (C
b ₁ , Cb ₂ , Cr ₁ and Cr ₂ ).

As described above, the MPEG encoder 10
In 2, the zigzag scan is performed in accordance with the regulations of MPEG2, and as shown in FIG. 21A, the DCT coefficients are arranged in order from the DC component and the low frequency component to the high frequency component in the order of the frequency component for each DCT block. When the scan of one DCT block is completed, the scan of the next DCT block is performed, and the DCT coefficients are arranged in the same manner.

That is, in the macroblock, the DCT block is
Lock Y₁, Y₂, Y₃And Y_Four, DCT block C
b₁, Cb₂, Cr₁And Cr₂For each of
The DCT coefficient is from DC component and low frequency component to high frequency component
Are arranged in order of frequency. And a series of runs
In the set consisting of the following level, [DC, AC₁, AC
₂, AC₃, ...]
As described above, variable length coding is performed.

In the recording side stream converter, the variable length coded and arranged DCT coefficients are once decoded to detect the delimiter of each coefficient, and the DCT coefficients are straddled across the DCT blocks constituting the macroblock. Collect by frequency component. This is shown in FIG. 21B. First, the DC components of the eight DCT blocks in the macroblock are grouped together, then the AC coefficient components having the lowest frequency components of the eight DCT blocks are grouped together, and hereinafter, the AC coefficients of the same order are grouped in order. The coefficient data is rearranged across the DCT blocks.

The rearranged coefficient data is DC
(Y₁), DC (Y₂), DC (Y₃), DC
(Y_Four), DC (Cb₁), DC (Cb₂), DC (C
r₁), DC (Cr ₂), AC₁(Y₁), AC₁(Y
₂), AC₁(Y₃), AC₁(Y_Four), AC₁(Cb
₁), AC₁(Cb₂), AC₁(Cr₁), AC
₁(Cr₂), ... Where DC, AC₁,
AC₂, ..., as described with reference to FIG.
Assigned to a set of runs followed by levels
These are respective codes of the generated variable length code.

The converted elementary stream in which the order of the coefficient data is rearranged by the recording side stream converter is supplied to the packing and shuffling section built in the ECC encoder 109. The length of the data of the macroblock is the same in the converted elementary stream and the elementary stream before conversion. Also, MPE
Even if the G encoder 102 has a fixed length in GOP (1 frame) units by bit rate control, the length varies in macro block units. In the packing and shuffling section, macro block data is applied to a fixed frame.

FIG. 22 schematically shows the packing process of macroblocks in the packing and shuffling section. The macroblock is fitted into a fixed frame having a predetermined data length and packed. The data length of the fixed frame used at this time is matched with the data length of the sync block which is the minimum unit of data at the time of recording and reproducing. This is because the shuffling and error correction coding processes are easily performed. In FIG. 22, for simplicity,
Assume that one frame contains 8 macroblocks.

Due to the variable length coding, as shown in FIG. 22A, the lengths of eight macroblocks are different from each other. In this example, the data of macroblock # 1, the data of # 3, and the data of # 6 are longer than the length of the data area of one sync block, which is a fixed frame.
The macroblock # 2 data, # 5 data, # 7 data, and # 8 data are short. The data of the macro block # 4 has a length substantially equal to that of one sync block.

By the packing processing, macroblocks are packed in a fixed length frame having a length of one sync block. Data can be packed without excess or deficiency because the amount of data generated in one frame period is controlled to be a fixed amount. As shown in an example in FIG. 22B, a macro block longer than one sync block is divided at a position corresponding to the sync block length. Of the divided macroblocks, a portion (overflow portion) protruding from the sync block length is packed in an area that is vacant in order from the beginning, that is, after the macroblock whose length is less than the sync block length.

In the example of FIG. 22B, macroblock # 1
First, the part that is out of the sync block length is packed after the macro block # 2, and when it reaches the sync block length, it is packed after the macro block # 5. Next, the part of the macro block # 3 that extends beyond the sync block length is packed behind the macro block # 7. Further, the portion of the macroblock # 6 that extends beyond the sync block length is packed behind the macroblock # 7, and the portion that extends further out of the macroblock # 7.
It is packed behind 8. In this way, each macro block is packed in the fixed frame having the sync block length.

The length of the variable length data corresponding to each macroblock can be checked in advance by the recording side stream converter. As a result, the packing unit can know the end of the macroblock data without decoding the VLC data and inspecting the contents.

FIG. 23 shows the ECC encoder 13 described above.
9 shows a more specific configuration. In FIG. 23, 164
Is an interface of the main memory 160 external to the IC. The main memory 160 is composed of SDRAM. The interface 164 arbitrates requests from the inside to the main memory 160, and performs write / read processing on the main memory 160. In addition, the packing section 137a, the video shuffling section 137b, and the packing section 137c constitute a packing and shuffling section 137.

FIG. 24 shows an example of the address configuration of the main memory 160. The main memory 160 is, for example, 64
It is composed of an M-bit SDRAM. Main memory 16
0 has a video area 250, an overflow area 251, and an audio area 252. Video area 250
Are four banks (vbank # 0, vbank # 1,
vbank # 2 and vbank # 3). Each of the four banks can store a digital video signal in one equal length unit. The 1-equalization unit is a unit for controlling the amount of generated data to a substantially target value, for example, 1 of a video signal
It is a picture (I picture). Part A in FIG. 24
Indicates the data portion of one sync block of the video signal. Data of a different number of bytes is inserted in one sync block depending on the format. In order to support a plurality of formats, the number of bytes which is more than the maximum number and is convenient for processing, for example 256 bytes, is the data size of one sync block.

Each bank of the video area is further divided into a packing area 250A and an output area 250B to the inner coding encoder. Overflow area 251
Corresponds to the above-mentioned video area and is composed of four banks. Further, the main memory 160 has a region 252 for processing audio data.

In the first embodiment, by referring to the data length indicator of each macroblock, the packing unit 137a stores the fixed frame length data and the overflow data which is a portion beyond the fixed frame in the main memory 160. Store in separate areas. The fixed frame length data is data that is equal to or shorter than the length of the data area of the sync block, and is hereinafter referred to as block length data. The area for storing the block length data is the packing processing area 250 of each bank.
It is A. When the data length is shorter than the block length, an empty area is created in the corresponding area of the main memory 160.
The video shuffling unit 137b performs shuffling by controlling the write address. Here, the video shuffling unit 137b shuffles only the block length data, and the overflow part is written in the area assigned to the overflow data without being shuffled.

Next, the packing unit 137c performs a process of packing the overflow portion into the memory for the outer code encoder 139 and reading it. In other words, 1 prepared from the main memory 160 to the outer code encoder 139
If the block length data is read into the ECC block memory, and if the block length data has a vacant area, the overflow portion is read and the block length is filled with the data. Then, when the data for one ECC block is read, the reading process is temporarily interrupted, and the outer code encoder 139 generates the parity of the outer code. The outer code parity is the outer code encoder 13
9 memory. When the processing of the outer code encoder 139 is completed for one ECC block, the outer code encoder 1
The data and the outer code parity are rearranged from 39 in the order of performing the inner code, and are written back to the packing processing area 250A of the main memory 160 and another output area 250B.
The video shuffling unit 140 performs shuffling in sync block units by controlling the address when writing back the data whose outer code has been encoded to the main memory 160.

In this way, the block length data and the overflow data are divided and the data is written into the first area 250A of the main memory 160 (first packing processing), and the overflow data is packed into the memory of the outer code encoder 139. Read in (second packing process), outer code parity generation, and data and outer code parity in the second area 250 of the main memory 160.
The process of writing back to B is performed in units of one ECC block.
By providing the outer code encoder 139 with a memory of the size of the ECC block, it is possible to reduce the frequency of access to the main memory 160.

A predetermined number of E's contained in one picture
When the processing of the CC block (for example, 32 ECC blocks) is completed, the packing of one picture and the encoding of the outer code are completed. Then, the data read from the area 250B of the main memory 160 via the interface 164 is processed by the ID addition unit 148, the inner code encoder 147, and the synchronization addition unit 150, and the parallel-serial conversion unit 124 outputs the output data of the synchronization addition unit 150. Is converted to bit serial data. The output serial data is processed by the partial response class 4 precoder 125. This output is digitally modulated as needed, and is supplied to the rotary head provided on the rotary drum 111 via the recording amplifier 110.

A sync block called null sync, in which effective data is not arranged, is introduced in the ECC block, and the EC is adapted to the difference in the format of the recorded video signal.
The configuration of the C block is made flexible.
The null sync is generated in the packing unit 137 a of the packing and shuffling block 137 and written in the main memory 160. Therefore, since the null sync has a data recording area, this can be used as a recording sync for the overflow portion.

In the case of audio data, even-numbered samples and odd-numbered samples of 1-field audio data form different ECC blocks. Since the ECC outer code sequence is composed of audio samples in the input order, the outer code encoder 136 generates an outer code parity each time an audio sample of the outer code sequence is input. The shuffling unit 137 performs shuffling (channel unit and sync block unit) by address control when writing the output of the outer code encoder 136 into the area 252 of the main memory 160.

Further, a CPU interface indicated by 126 is provided to receive data from an external CPU 127 functioning as a system controller and set parameters for internal blocks. In order to support multiple formats, it is possible to set many parameters such as sync block length and parity length.

The "packing length data" as one of the parameters is sent to the packing units 137a and 137b, and the packing units 137a and 137b determine the fixed frame (the "sync block length" in FIG. 22A) based on this. (Length shown as) with VLC data.

The "pack number data" as one of the parameters is sent to the packing section 137b, and the packing section 137b determines the number of packs per sync block based on this, and the data for the determined number of packs. Are supplied to the outer code encoder 139.

The "video outer code parity number data" as one of the parameters is sent to the outer code encoder 139, and the outer code encoder 139 outputs the outer code of the video data for which the number of parities based on this is output. Encode.

Each of the "ID information" and "DID information" as one of the parameters is sent to the ID adding section 148, and the ID adding section 148 receives the ID information and the DID information.
The ID information is added to the data string of unit length read from the main memory 160.

Each of the "video inner code parity number data" and the "audio inner code parity number data" as one of the parameters is an inner code encoder 149.
Then, the inner code encoder 149 encodes the inner code of the video data and the audio data for which the number of parities is generated based on them. It should be noted that "sync length data" which is one of the parameters is also sent to the inner code encoder 149, whereby the unit length (sync length) of the inner coded data is regulated.

Further, shuffling table data as one of the parameters is stored in the video shuffling table (RAM) 128v and the audio shuffling table (RAM) 128a. The shuffling table 128v performs address conversion for shuffling the video shuffling units 137b and 140. The shuffling table 128a performs address conversion for the audio shuffling 137.

Next, the above-mentioned qauntizer_s
Approximate conversion of the quantization scale by the call_code will be described. FIG. 25 shows qa in MPEG2.
The relationship between unizer_scale_code and the quantization scale will be shown. Qauntiz shown in the left column
The two types of quantization scales shown in the right column are associated with er_scale_code, and both poetry steps are referenced by quntizer_scale_code. The left side of the right column is the quantization scale with linear steps, and q_sc
It is indicated by ale_type = 0. On the right side of the right column is the quantization scale in which the step is non-linear, and q_scal
It is indicated by e_type = 1.

The non-linear quantization scale for q_scale_type = 1 is q_scale_type = 0.
Corresponding quantum in the linear quantization scale of
With respect to the izer_scale_code, it is associated with a finer step in a region having a small value and a coarser step in a region having a large value. Also, q_sc
In the case of ale_type = 0, the maximum value of the quantization scale is “64”, whereas q_scale_type =
In No. 1, the maximum value of the quantization scale is “112”.

These quantization scales are usually fixedly used on the device side. For example, q_scale_type
In a device adapted to handle a stream of e = 1, the quantization scale shown on the right side of the right column in FIG. 25 is fixedly used. That is, this quantizer scale is referred to by the quantizer_scale_code in the input stream and used for decoding.

In this embodiment, the QST checker 5
30A, q_sc of the input MPEG ES
Check ale_type, and if the value is "0",
In the QST and QSC rewriting unit 530B, q_scale
Rewrite the value of _type to "1". At the same time, qquantizer_scale_co is set so that the quantization scale is q_scale_type = 1, that is, the quantization scale approximated to a non-linear quantization scale.
Rewrite de.

FIG. 26 shows this q_scale_type.
An example of rewriting the quantization scale will be shown. Q in left column is for q_scale_type = 0 before rewriting
an quantizer scale and an quantizer_scale_code. Right column is quntizer_scal
The figure shows a state after rewriting e_code. q_scale_t
The value of type is rewritten from "0" to "1". qa
The unizer_scale_code is rewritten from the value on the right side of the left column to the value on the left side of the right column. Also, in the right column, the rewritten qauntizer
Q_scale_, which corresponds to _scale_code
The quantization scale of type = 1 is shown on the left.

For example, the QST and QSC rewriting section 530B
Has a memory, and the conversion table based on the left column right side and the right column left side in FIG. 26 is stored in advance in the memory of the QST and QSC rewriting unit 530B. QST, QSC rewriting section 5
In 30B, qauntiz in the input stream
This conversion table is referred to based on er_scale_code, and quntizer_scale_co
re is rewritten.

In the figure, "or" indicates that either of the two values on both sides is used, and "quntizer_s" is used.
The corresponding side of the call_code and the quantization scale is used.

This quntizer_scale_c
The rules for rewriting the ode will be described. For example,
On the stream of q_scale_type = 0, qa
Consider the case where there is a macroblock with unizer_scale_code = 10. For the quantization scale of this macroblock, refer to the left column of FIG.
The value is “20”.

This is indicated by q_scale_type as indicated by the arrow from the right side of the left column to the left side of the right column in FIG.
= 1 and quntizer_scale_code = 1
Rewrite as 4. Then, as shown in the right column of FIG. 26, quntizer_scale_code = 14
The value of the quantization scale corresponding to is also "20" as before rewriting.

As another example, q_scale_t
On the stream of type = 0, quntizer_s
It is assumed that there is a macroblock for which call_code = 17. The quantization scale of this macroblock has a value of "34" with reference to the left column of FIG.

As described above, according to the arrow in FIG. 26, q_scale_type = 1, qauntize
Rewrite as r_scale_code = 18. Then, as shown in the right column of FIG. 26, the quntizer
The value of the quantization scale corresponding to _scale_code = 18 is "32".

Also, as shown in parallel with "or" in the figure, q_scale_type = 1, qaunti
When rewritten as zer_scale_code = 19, quntizer_scale_code = 18
The value of the quantization scale corresponding to is 36.

As described above, in this another example, {q_scale_type = 0, qauntizer described above is used.
_Scale_code = 10} and {q_scale
_Type = 1, qauntizer_scale_c
Although it is not a perfect correspondence relationship such as the relationship with ode = 14}, it can be approximated by the nearest quantization scale.

Thus, according to the rules shown in FIG. 26, q_scale_type and qauntizer
By rewriting _scale_code, q_sc
The quantization scale at ale_type = 1 is q_
It can be approximated to the quantization scale at scale_type = 0.

Therefore, q_scale_type =
It is a device designed to handle MPEG ES that is defined as 1.
MPE entered as q_scale_type = 0
By performing this rewriting process on the GES, it is possible to suppress a large deviation of the brightness, saturation, and hue from the original image in a reproduced image obtained by decoding the rewritten MPEGES.

FIG. 27 schematically shows the position of q_scale_type. The q_scale_type is included in the picture coding extension 10 (see FIG. 11), and as shown in FIG. 27, the 28th bit from the end of extension_start_code representing the start of the picture or the coding extension 10 is allocated. As described above with reference to FIG. 16, since the boundaries of the code are divided in byte units up to the picture layer, the variable length code is not decoded,
q_scale_type can be extracted and rewritten.

For example, by performing byte matching for each 1 byte (8 bits), the start code is represented by [00
00 01 xx] is detected, and the part of [xx] is [B
5], it can be determined that the detected start code is the start code of the picture coding extension 10. The position counting 28 bits from the next bit of this start code is q_scale_type. The value of this position is detected by the QST checker 530A, and if the value is "0", the QST / QSC rewriting unit 530B is instructed to rewrite the value of the position from "0" to "1". Together with qauntizer_sca
It is instructed to rewrite le_code.

Quntizer_scale_cod
e is included in the slice header 13 and the macroblock header 14. Qau included in the slice header 13
nizer_scale_code specifies the quantization step of the head macroblock of the slice. The quantization step of each macroblock included in a slice, excluding the head of the slice, includes a quantizer_scale_co included in each macroblock.
specified by de. In this embodiment, as described above, MP is performed with 1 slice = 1 macroblock.
Since the EG ES is configured, the slice header 13
Included in qantizer_scale_code
Rewrite.

FIG. 28 shows the qauntizer_scal.
The position of e_code is schematically shown. qauntize
Five bits from the rear of the slice start code 12 indicating the start of the slice header 14 are allocated to r_scale_code. As described above, in the slice layer, since only the slice start code 12 is divided in byte units, it is not necessary to decode the variable length code and the qaun
It is possible to rewrite the timer_scale_code.

For example, by performing byte matching for each byte, the start code is represented by [00 00 01
xx] is detected, and the part of [xx] is [01] to [A].
F], it can be determined that the detected start code is the slice start code 12. 5 bits immediately after this slice start code 12 are used as a quntizer
_Scale_code is represented. As mentioned above,
Q_scale_ty by the QST checker 530A
When it is detected that pe is “0”, the QST checker 530A instructs the QST and QSC rewriting unit 530B to rewrite quntizer_scale_code to a predetermined value. Based on this instruction,
Rewriting of quntizer_scale_code is performed.

In the above description, the QST checker 530A is used.
Q_scale_type check by QS,
Q_scale_t in T, QSC rewriting unit 530B
ype and quntizer_scale_cod
Although e is rewritten without decoding the variable length code, this is not limited to this example. For example, the QST conversion unit 530 may be further provided with a variable length code decoder so that the above-mentioned check and rewrite processing is performed after decoding the input variable length code of MPEG ES.
In this case, even if one slice includes a plurality of macroblocks, for each macroblock,
The above checking and rewriting can be performed.

In the above description, MPEG2 is preliminarily used outside the device.
An example in which the above-described processing by the QST conversion unit 530 is performed on a stream encoded and input by the method has been described, but this is not limited to this example. For example, as shown in FIG. 29, the QST conversion unit 530 can be checked for both the stream encoded and input outside the device and the stream encoded by the MPEG encoder 511 inside the device. May be. Although not shown, the QST converter 5 is provided on the reproducing side, that is, on the output side of the MPEG decoder 518.
It is also possible to arrange 30.

In the present invention, the reverse process to the above, that is, the stream with q_scale_type = 1 is changed to q_
q_scale_type and qaun to approximately convert to a stream with scale_type = 0
It is possible to rewrite the timer_scale_code.

However, this inverse conversion process is not preferable for the following reasons. The above q_scale_t
For conversion from type = 0 to q_scale_type = 1, the range of the quantization scale prepared as q_scale_type = 1 is q_scale_type =
This is true because it is wider than the range of the quantization scale prepared as 0. In the reverse conversion, for example, {q_scale_type = 1, qauntiz
The value of the quantization scale when er_scale_code = 31} is “112”. On the other hand, q_scal
At e_type = 0, the value of the quantization scale closest to this value is “62”. In this way, in the reverse conversion, the error of the quantization scale becomes very large, and the brightness, saturation, and hue of the reproduced image may differ greatly from the original image, so it is not an effective method. I can't say.

Although the present invention has been described above as applied to a digital VTR, it is not limited to this example. For example, using the QST conversion unit 530 independently, q_scale_type and qquantize
It can also be configured as an r_scale_code conversion device.

[0171]

As described above, according to the present invention, M
Q_sca in the stream encoded with PEG2
le_type is detected, and detected q_scale_
q_scale_ in the stream based on the value of type
Type is rewritten and the original q_scale_t
The index of the quantization scale indicated by ype is rewritten to the index that approximates the quantization scale indicated by the rewritten q_scale_type.

Therefore, for example, q_scale_type
When the present invention is applied to a device fixed at e = 1, q_
Even if a stream encoded with scale_type = 0 is input, q_ of the input stream
The scale_type is rewritten from “0” to “1” and the index of the quantization scale of the input stream is rewritten to the index approximated to the index of q_scale_type = 1. As a result, there is an effect that even a device fixed to q_scale_type = 1 can capture a stream of q_scale_type = 0.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a VTR that records and reproduces a baseband signal using a magnetic tape as a recording medium.

FIG. 2 is a block diagram showing a basic configuration of a VTR that records and reproduces a stream in which a video signal is encoded by the MPEG2 system.

FIG. 3 is a block diagram showing a basic configuration of a VTR according to the present invention.

FIG. 4 is a schematic diagram schematically showing a hierarchical structure of MPEG2 data.

FIG. 5 is a schematic diagram showing the contents and bit allocation of data arranged in an MPEG2 stream.

FIG. 6 is a schematic diagram showing the content and bit allocation of data arranged in an MPEG2 stream.

FIG. 7 is a schematic diagram showing the content and bit allocation of data arranged in an MPEG2 stream.

FIG. 8 is a schematic diagram showing the contents and bit allocation of data arranged in an MPEG2 stream.

FIG. 9 is a schematic diagram showing the content and bit allocation of data arranged in an MPEG2 stream.

FIG. 10 is a schematic diagram showing the content and bit allocation of data arranged in an MPEG2 stream.

FIG. 11 is a schematic diagram showing the content and bit allocation of data arranged in an MPEG2 stream.

FIG. 12 is a schematic diagram showing the content and bit allocation of data arranged in an MPEG2 stream.

FIG. 13 is a schematic diagram showing the content and bit allocation of data arranged in an MPEG2 stream.

FIG. 14 is a schematic diagram showing the content and bit allocation of data arranged in an MPEG2 stream.

FIG. 15 is a schematic diagram showing the content and bit allocation of data arranged in an MPEG2 stream.

FIG. 16 is a diagram for explaining alignment of data in units of bytes.

FIG. 17 is a schematic diagram specifically showing a header of an MPEG stream.

FIG. 18 is a block diagram showing an example of a configuration of a recording / reproducing apparatus applicable to the present invention.

FIG. 19 is a schematic diagram showing an example of a track format formed on a magnetic tape.

[Fig. 20] Fig. 20 is a schematic diagram for explaining a method of outputting a video encoder and variable length coding.

FIG. 21 is a schematic diagram for explaining rearrangement of the output order of the video encoder.

FIG. 22 is a schematic diagram for explaining a process of packing the data in which the order is rearranged in a sync block.

FIG. 23 is a block diagram showing a more specific configuration of the ECC encoder.

FIG. 24 is a schematic diagram showing an example of an address configuration of a main memory.

FIG. 25 is a figure of qquantizer_s in MPEG2.
It is an approximate line figure showing the relation between call_code and a quantization scale.

FIG. 26 is a schematic diagram showing an example of rewriting q_scale_type and a quantization scale according to the present invention.

FIG. 27 is a schematic diagram schematically showing the position of q_scale_type.

FIG. 28: quntizer_scale_code
It is an approximate line figure showing roughly the position of.

FIG. 29 is a block diagram showing a basic structure of another example of the VTR according to the present invention.

[Explanation of symbols]

1 ... Sequence header code, 2 ... Sequence header, 3 ... Sequence extension, 4 ... Extension and user data, 5 ... GOP start code, 6 ...
GOP header, 7 ... user data, 8 ... picture start code, 9 ... picture header, 10 ...
..Picture coding extension, 11 ... Extension and user data, 12 ... Slice start code, 13 ...
・ Slice header, 14 ... Macroblock header,
101 ... SDI receiver, 102 ... MPEG encoder, 106 ... Recording side multi-format converter (MFC), 108 ... SDTI receiver, 109
... ECC encoder, 112 ... Magnetic tape, 1
13 ... ECC decoder, 114 ... Playback side MF
C, 115 ... SDTI output section, 116 ... MPE
G decoder, 118 ... SDI output section, 137a, 1
37c ... Packing unit, 137b ... Video shuffling unit, 139 ... Outer code encoder, 140 ...
..Video shuffling, 149 ... Inner code encoder, 530 ... QST converter, 530A ... QST
Checker, 530B ... QST, QSC rewriting unit

Continued front page    F-term (reference) 5C053 FA14 FA21 GA11 GB22 GB26                       GB29 GB32 GB38 HA40 JA21                 5C059 KK01 KK41 MA00 MA01 MA23                       MC11 MC38 ME01 PP04 RC11                       SS11 TA48 TC45 UA02 UA05                 5D044 AB05 AB07 BC01 CC03 DE15                       DE43 DE44 EF05 FG18 GK08                 5J064 AA01 BA09 BA16 BB09 BC01                       BC02 BC16 BD03 BD04

Claims (4)

[Claims] 1. A quantization scale for compression encoding can be selected from a plurality of sets of quantization scales to be used, and the quantization scale is referred to by an index common to the plurality of sets of quantization scales. In the signal processing device to which the stream encoded by the compression encoding method described above is input, the set of quantization scales used in the compression encoding is input from the input stream that is compression encoded. Detecting the parameter shown, determining means for determining whether the detected parameter indicates a predetermined set of the quantization scale, and rewriting the parameter in the input stream, the quantization scale And a rewriting unit that rewrites the index to be referred to, and the judging unit described above judges whether or not the above-mentioned pattern in the input stream is included. When it is determined that the parameter indicates a set other than the predetermined set, the rewriting unit rewrites the parameter in the input stream to a parameter indicating the predetermined set and also sets the parameter other than the predetermined set. The index referring to the quantization scale in the input stream is rewritten with an index that approximately transforms the quantization scale of the set to the predetermined quantization scale of the predetermined set. A characteristic signal processing device. 2. The signal processing device according to claim 1, wherein the stream is compression-coded using a variable-length code, and the stream further comprises a decoding unit that decodes the variable-length code. The signal processing device, wherein the determining means and the rewriting means are configured to perform the determination, the parameter rewriting, and the index rewriting after the variable length code is decoded by the decoding means. 3. The signal processing device according to claim 1, wherein the compression encoding system is a system based on the MPEG2 system. 4. A quantization scale for compression encoding can be selected and used from a plurality of sets of quantization scales, and the quantization scale is referred to by an index common to the plurality of sets of quantization scales. In the signal processing method in which the stream encoded by the compression encoding method is input, the set of the quantization scale used in the compression encoding is input from the stream input by the compression encoding. Detecting the parameter shown, determining step of determining whether the detected parameter indicates a predetermined set of the quantization scale, and rewriting the parameter in the input stream, and the quantization scale And the step of rewriting the index that refers to When it is determined that the parameter in the stream indicates a group other than the predetermined group, in the rewriting step, the parameter in the input stream is rewritten to a parameter indicating the predetermined group, and Rewrite the index that refers to the quantization scale in the input stream with an index that approximately converts the quantization scale of a set other than the predetermined set to the quantization scale of the predetermined set. A signal processing method characterized by the above.