JP2000115581A - Video signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a correction processing function for suppressing the artifact generation of a processing object video signal due to the influence of an unknown transmission line without transmitting a reference signal in a blanking period. SOLUTION: The video signal 21 obtained by decoding encoded video data 20 by a video decoder 10 is transmitted as an analog video signal 22 by a D/A converter 11. In a video receiver 1, the signal 22 is re-sampled and digitized by an A/D converter 12 and then undergoes the descrambling processing of the video signal by a digital signal processing part 14. In this system, a reference video signal the pixel value of which is fixed by the unit of a macro block or a block is included in the signal 22 and transmitted. Then, the original position of the valid picture area of the video signal is corrected by a video signal correcting part 13 at the prestage of the part 14 by using this reference video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing apparatus for digitally processing a digital video signal transmitted through a transmission line having unknown transmission characteristics including an analog transmission line, and more particularly to a code signal such as MPEG2. The present invention relates to a video signal processing device for a video signal scrambled in accordance with the conversion.

[0002]

2. Description of the Related Art For the purpose of protecting the rights of copyrighted works including audio and video, various encryption techniques have been researched and developed or put into practical use in order to prevent unauthorized copying and unauthorized access.

For example, in a DVD (Digital Versatile Disc) using MPEG2 video coding, a reproduction area is limited by a region code (region code), and a CSS (Co
ntents Scrambling System).

As scrambling means for a baseband video signal, a line rotation for setting one random cut point for each line and exchanging left and right of the cut point or a line permutation for randomly exchanging scan lines is provided. There is a technique called. The line rotation is used as scrambling of pay programs of satellite broadcasting and CATV for access restriction in conjunction with a billing system.

In order to prevent illegal copying in a consumer analog VTR, AGC in a vertical blanking period is performed.
Although no trouble occurs when a signal or a color stripe signal is manipulated and displayed on a TV, a copy guard technique of Macrovision, which makes normal recording on a VTR impossible, is widely used.

Further, a technique called “digital watermark” (digital watermark) corresponding to digital contents including audio or video is known. Digital watermarking is a technique for embedding data in a baseband signal such as voice or image or encoded data so that the data is not perceived by eyes or ears. Examples of information to be embedded in the digital watermark include copyright information, copy generation management information, reproduction control information, and scramble key information.

[0007] Each of the various methods described above has advantages and disadvantages. For example, management using a region code allows unconditional playback in a specified area, and CSS
The encryption of data by the method described above does not prohibit reproduction by a legitimate player. Therefore, the region code or C
In SS, it is possible to prevent the encoded data itself from being copied, but it is not possible to prevent illegal copying of the decoded video signal. Further, in a copy guard system using an analog VTR, the effect of the copy guard is not necessarily guaranteed depending on the type of the VTR, and since the operation is performed only on the synchronization signal portion, it is hard to say that the resistance to an unauthorized attack is high. . Furthermore, embedding of copyright information by a digital watermark or the like does not necessarily limit technically preventing illegal copying of a video signal.

That is, in order to prevent unauthorized copying of a video signal, it is necessary to use a stronger copyright protection means for the video signal itself. However, when a conventional moving image scrambling method such as a line rotation is used, the D.C.
When encoding is performed by MPEG2 used in VD or digital broadcasting, the encoding efficiency is reduced as compared with the encoding of non-scrambled images, and the image quality of reproduced images is deteriorated. This is because conventional video scrambling is a technique that makes the original video less visible by reducing the spatio-temporal correlation of the image by random operation on the image, and increases the coding efficiency by using the spatio-temporal correlation of the image. This is because the operation is inconsistent with the motion compensation prediction / orthogonal transform coding such as MPEG2.

As a method for solving such a problem, a frame which is not used as a reference image in inter-frame predictive coding is selected, and a pixel value is replaced in units of a macroblock or slice in the frame, or the frame value is replaced. A scheme is conceivable in which scrambling is performed by both, and after this scrambling, inter-frame prediction coding is performed. In addition, it is possible to prevent the above-described decrease in coding efficiency for the polarity inversion of all pixel values, that is, for the bit inversion operation. Furthermore, scrambling due to rotation or replacement of the color space axis is also effective in preventing a decrease in coding efficiency. By combining these polarity inversions and rotation / swapping of the color space axis, it is possible to perform video scrambling while suppressing a decrease in encoding efficiency in MPEG2.

[0010] However, the video signal scrambled in this way is encoded by an encoding method such as MPEG2.
Transmission via an analog transmission path whose transmission characteristics are unknown,
When the analog video signal received on the receiving side is resampled and digitized by an A / D converter and then descrambled by digital signal processing, the frequency and phase characteristics, echo, dynamic range distortion, Due to the influence of a zero-level offset, a phase shift of a resampling clock, and the like, a visual artifact may be accompanied by a descrambled image.

Generally, a waveform equalization technique is known as a means for correcting unknown transmission characteristics. An adaptive filter is usually used for waveform equalization, receives a signal in which a known reference signal is embedded, and determines the tap gain of the adaptive filter by learning. For example, in the MUSE system, which is a sample value transmission of an HDTV signal, a waveform equalizer using a transversal type adaptive filter is generally used in a decoder in order to remove ringing due to transmission path echo and resampling. In order to perform learning of the adaptive filter, an impulse signal is transmitted as a reference signal in a blanking period in a MUSE video signal. On the other hand, in the video coding of MPEG2, usually, only the signal in the effective image area is coded and transmitted, so that a special data format and a decoding process are defined in order to send the reference signal during the blanking period. A need arises, which is difficult within the framework of MPEG2 coding.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention uses a reference video signal having a fixed pixel value for each predetermined area unit such as a macroblock or a block unit to generate a processing costume video signal. Processing such as position correction (positioning of an effective image area), correction of a gain and a DC offset, learning of a waveform equalization filter, or estimation of a video format conversion parameter is performed.

That is, the first video signal processing apparatus according to the present invention corrects the position of the video signal to be processed using the reference video signal provided with the video signal to be processed and having a fixed pixel value for each predetermined area unit. And a correction means for performing the following. In this case, the position correction may be performed independently for each signal component of the video signal, or may be uniformly performed for all the signal components.

A video signal encoded by the MPEG2 system or the like is transmitted to a receiving side via a storage medium or a digital transmission path, and the encoded data of the video signal received by the receiving side is decoded. Is assumed to be transmitted via an analog transmission path and displayed on a display device. Here, the baseband video signal transmitted through the analog transmission path is resampled and digitized by an A / D converter, subjected to some digital processing, and returned to an analog signal again by a D / A converter. Considering the case of displaying, there are various influences of the transmission characteristics of the analog transmission path, and image artifacts may occur due to processing after resampling.

As such an artifact, for example, there is a case where a shift occurs at the head of an effective line or the head position of an effective pixel in the line due to a characteristic or setting unique to each device. In digital processing after resampling,
When strictness is required for the lines and pixel positions of the effective area of the video, the shift of the effective area in the transmission system may lead to a fatal artifact. For example, when descrambling a scrambled video by shuffling a line or a horizontal pixel position, it is necessary to position the pixel position in the image exactly.

Here, in the first video signal processing apparatus according to the present invention, the pixel value is constant in a predetermined area unit, specifically, for example, a unit corresponding to a multiple of a DCT block such as a macro block or a block. To define a known reference video signal, intra-frame encode the reference video signal according to the MPEG2 system, perform analog transmission and re-sampling of the decoded signal of the reference video signal, and perform matching with the known reference video signal. Accordingly, it is possible to detect the displacement of the effective image area.

In MPEG2 encoding, an arbitrary video signal is not reversible due to the effects of DCT / IDCT operation accuracy and DCT coefficient quantization. However, as for the DC component of each DCT block of the intra macroblock for which no motion compensation prediction is performed, the value of the basis function is an integer.
It is hardly affected by the calculation accuracy of CT / IDCT.
In the EG2 system, the DC component of the intra macroblock is
Since it is not affected by the quantization control for normal rate control, it is reversible through encoding / decoding without being affected by coding distortion. If a reference video signal is created using this feature, the reference video signal is received as a waveform affected only by a pure transmission characteristic, so that accurate positioning can be performed.

A second video signal processing device according to the present invention comprises:
The image processing apparatus further includes a correction unit that corrects a gain and a DC offset of the processing target video signal using the same reference video signal. Also in this case, the correction of the gain and the DC offset may be performed independently for each signal component of the video signal, or may be uniformly performed for all the signal components.

In a video signal transmission system, it is desirable that the gain is 1 and the additional DC offset is 0. However, the gain is actually 1 due to the characteristics and settings unique to each device.
, A non-zero DC offset is added, or the gain is not linear but non-linear. Therefore, the reproducibility of the video may be deviated due to the analog transmission, or the image may be very unnatural, particularly when performing processing depending on pixel values after resampling, such as descrambling processing such as polarity inversion. .

According to the second video signal processing device, the correction amounts of the gain and the DC offset are determined by using the above-mentioned reference video signal, and the video signal is corrected accordingly, whereby these signals are transmitted in the transmission system. It is possible to eliminate additional factors.

A third video signal processing device according to the present invention comprises:
Tap gain determining means for determining a tap gain of a waveform equalizing filter for equalizing the waveform of the processing target video signal using the same reference video signal. In the determination of the tap gain, the correction of the gain and the DC offset may be performed independently for each signal component of the video signal, or may be uniformly performed for all the signal components.

When a video signal is transmitted through an analog transmission path and resampled, artifacts such as echoes in the transmission path and ringing due to a shift in sampling phase and a cutoff frequency in resampling occur. To remove these artifacts, a transversal type adaptive filter is generally used as a waveform equalization filter. For learning of the adaptive filter, an impulse waveform or a step waveform having a flat frequency characteristic is preferable.

In this regard, in the third video signal processing device, it is possible to generate an arbitrary known step waveform by using the above-mentioned reference video signal, thereby learning the adaptive filter, that is, the waveform equalizing filter. Can be set efficiently.

A fourth video signal processing device according to the present invention comprises:
A conversion parameter estimating means for estimating a conversion parameter when the signal component of the processing target video signal is converted by using the same reference video signal provided together with the converted processing target video signal, An inverse transform parameter calculating means for calculating an inverse transform parameter for each signal component from the transform parameter estimated by the parameter estimating means; and an inverse of the signal component of the video signal to be processed by the inverse transform parameter calculated by the inverse transform parameter calculating means. And inverse conversion means for performing conversion.

Here, the conversion of the signal component of the video signal means
Conversion of a 4: 2: 0 component signal to a 4: 2: 2 component signal, conversion of a 4: 2: 0 component signal to a YIQ composite or component signal, and conversion of a YCbCr signal to an RGB signal; When such conversion is performed, a conversion parameter is estimated using the same reference video signal as described above, an inverse conversion parameter of a video signal component is calculated from the estimated conversion parameter, and the video signal is calculated based on the inverse conversion parameter. Is inversely converted, and the video signal before conversion is reproduced.

In the MPEG2 standard, a 4: 2: 0 signal is defined as a main profile. This is because the video signal is composed of two types of color difference signals (C) composed of a luminance signal (Y) and half the number of pixels both horizontally and vertically with respect to the luminance signal.
b, Cr). General MPEG such as DVD and satellite digital broadcasting
In the two video application, the main profile of MPEG2 is adopted, and the main profile encodes a video signal of 4: 2: 0 format. On the other hand, the output video signal from the decoder is usually 4:
2: 2 component digital or analog signal,
The signal is converted into an RGB analog component signal, an S-video signal, a composite signal, or the like, and output. Therefore, the signal format is converted at the output stage of the MPEG2 decoder inside the decoder.

In particular, regarding the number of vertical lines of the color difference signal, in any of the above output signal formats,
The number of lines of the luminance signal is the same as that of the luminance signal, and the oversampling of the color difference signal in the vertical direction is performed twice from the 4: 2: 0 signal. When it is desired to perform pixel processing at an encoded 4: 2: 0 video signal level by digital processing after resampling on a video signal that has undergone these format conversions, inverse conversion for these conversions is performed. There is a need.

According to the fourth video signal processing apparatus, for example, by transmitting a known reference video signal at a 4: 2: 0 signal level, it is possible to estimate the conversion coefficients of these format conversion processes. The parameters of the inverse filter are calculated from the thus estimated transform coefficients, and the inverse transform to the encoded 4: 2: 0 signal can be performed.

A fifth video signal processing device according to the present invention comprises:
For each partial area such as a plurality of continuous macroblocks, the spatial change amount of the pixel value in the overlap area or the interpolation area is minimized for the processing target video signal in which the overlap area or the interpolation area of the pixel value is provided. It is characterized by having means for selecting or generating the pixel value of the processing target image signal.

The sixth video signal processing device according to the present invention is an extension of the fifth video signal processing device,
Whether to provide an overlap area or an interpolation area of pixel values is set in a predetermined video signal unit, and for a predetermined video signal unit portion in which no overlap area or an interpolation area is provided, selection of a pixel value of an effective image area Alternatively, predetermined additional data corresponding to the number of pixels to be reduced due to generation is embedded in the effective image area of the processing target video signal. Here, the predetermined additional data basically includes any of the above-described reference video signal, information relating to attributes in frame units, or information relating to the scramble key of the video signal, but is limited to such information. Not something.

Then, the sixth video signal processing device is provided with the fifth video signal processing device.
In addition to the configuration of the video signal processing device of the above, additional data detection means for extracting the above-mentioned predetermined additional data, and means for replacing the additional data detected by the additional data detection means with a predetermined video signal and outputting Have.

The video signal output from the MPEG2 decoder is a digital sample value sequence, which is referred to as D / A
When the data is converted and transmitted via the analog transmission path, the influence of the interaction between samples depending on the transmission characteristics occurs.

According to the fifth video signal processing apparatus, for example, an overlapping area or an interpolating area of pixel values is provided for a portion where it is desired to reduce the influence of an effect between samples accompanying transmission via an analog transmission path. By selecting or generating pixel values so as to minimize the amount of spatial change in pixel values in the region or the interpolation region, it is possible to reduce the interaction between adjacent pixel samples.

When such an overlap area or interpolation area is inserted, the effective effective image area is reduced. Conversely, when the number of pixels to be transmitted is constant and these areas are not inserted, the effective image area is expanded.

In this regard, according to the sixth video signal processing apparatus, when the number of pixels in the final effective area is fixed, the extended portion of the effective area in the video in which the overlap area or the interpolation area is not inserted is set. It is possible to transmit other additional data different from the video data by utilizing the additional data.
Using this area, the above-described reference video signal can be transmitted, and attribute information of each frame, key information for descrambling each frame, and the like can be transmitted. Here, the attribute information of each frame is MP
These include encoding parameters in EG2 encoding, data accompanying the contents of the content, copyright information, reproduction control information indicating copy prohibition, and the like.

Since the additional data is mapped to the effective area of the video signal, if it is output as it is as a video signal, it will be displayed on the display device. Therefore, in the sixth video processing device according to the present invention, after extracting the additional data, the area is replaced with predetermined video data (for example, black or gray) and output, so that an unsightly video is displayed on a part of the screen. Can be prevented.

A seventh video signal processing apparatus according to the present invention comprises:
The video signal processing apparatus according to the present invention further comprises a descrambling means for inputting a scrambled video signal as a video signal to be processed in the first to sixth video signal processing devices and descrambling the video signal. This descrambling means is provided downstream of the correction means when applied to the first and second video signal processing devices, and is provided downstream of the waveform equalization filter when applied to the third video signal processing device. A means for selecting or generating a pixel value of an effective image area of a processing target video signal when applying to the fifth and sixth video signal apparatuses; The detected additional data is arranged at a stage subsequent to the means for replacing the output with a predetermined video signal and outputting the video signal. With such a configuration, it is possible to reduce artifacts caused by descrambling.

Here, scrambling is performed, for example, by (1) replacing pixel data in the horizontal direction in units of a plurality of continuous macroblocks in a frame with respect to pixel data corresponding to an encoded macroblock, and (2) encoding slices. (3) Invert the pixel value in the vertical direction in units of partial areas such as slices in a frame for pixel data equivalent to (3) Invert the polarity of at least one signal component such as chromaticity / color difference of a video signal, or (4) It includes either the replacement or rotation of the signal components of the video signal. In this case, in particular, in scrambling by replacing pixel values in units of partial regions such as a plurality of macroblocks or slices, pixel values may not be replaced in a partial region of an outer peripheral portion in a screen.

Of these scramble methods, in the methods (1) and (2), since the deviation of the origin position of the effective screen is fatal, the positioning of the effective screen is performed by the first video signal processing apparatus described above. It is effective to do. However,
If the correction amount of the origin position of the effective area of the video signal after resampling is not 0, a part of the effective image may be missing. In this case, if the missing pixel is located inside the effective screen in the image after descrambling, the reproduced image will be a distorted image. On the other hand,
When performing scrambling in (1) or (2), pixel values of macroblocks or blocks in the outer peripheral portion of the original effective image area are not replaced, so that the effective image is not re-sampled. Even if a part is missing, it is possible to prevent a significant effect on the descrambled image.

In the scrambling methods (3) and (4), when the gain of the transmission path and the DC offset for each video signal component are large, the video signal is determined by the presence / absence of polarity reversal and the presence / absence of signal component replacement. Greatly changes, and the image after descrambling becomes a visually unnatural image. According to the above-described second video signal processing device feature, it is possible to correct the gain and the DC offset prior to descrambling, and it is possible to remove unnaturalness of the video after descrambling.

In any scrambling method, when resampling is performed by resampling after passing through an analog transmission path, ringing due to a phase shift of a reproduced clock or a shift of a cutoff frequency in resampling or transmission is performed. The image after descrambling may be accompanied by artifacts due to the influence of the echo on the road and the like. Regarding this point, the above-mentioned third video signal processing apparatus performs waveform equalization processing by an adaptive filter on the video signal after resampling prior to descrambling processing, so that most of these effects are obtained. Can be removed.

Each of the above scrambling processes is performed under the video signal format encoded by MPEG2, and the output video signal format after decoding is converted into another video signal format and output. Consider a case where a video signal is resampled and a descrambling process is performed. In this case, in order to perform accurate descrambling, it is necessary to return the resampled video signal to the video signal format at the time of encoding and then perform the descrambling process. According to the above-described fourth video signal processing apparatus, it is possible to automatically estimate the format conversion parameter of the output video signal, and to calculate a parameter for inverse conversion from the estimated conversion parameter, so that the It is possible to accurately return to the video signal format.

An eighth video signal processing apparatus according to the present invention comprises:
A reference video signal reproducing unit that reproduces the reference video signal from a recording medium that records a reference video signal having a fixed pixel value for each predetermined area unit such as a macroblock or a block unit; (A) the position correction amount of the video signal,
(b) video signal gain and DC offset correction amount,
(c) tap gain of a waveform equalization filter for a video signal,
(d) parameter determining means for determining at least one parameter of an inverse conversion parameter for the converted signal component of the video signal, parameter storing means for storing the parameter determined by the parameter determining means, and recording the reference video signal Processing target video signal reproducing means for reproducing the processing target video signal recorded on the same or different recording medium as the recording medium, and the processing target video signal reproduced by the processing target video signal reproducing means are stored in the parameter storage means. Correction means for correcting according to the set parameters.

The reference video signal is recorded on a recording medium different from the video content of the main part, or is recorded on the same recording medium as the video content of the main part so as to be reproduced prior to reproduction of each video content. Alternatively, the video content is recorded in a predetermined area in the effective screen of each video content on the same recording medium as the video content of the main part.

That is, consider a case where video data is encoded and recorded on a storage medium such as an optical disk, and after the video data is decoded and reproduced, a descrambling process is performed. In this case, the reference video signal in the present invention is (a) recorded on a separate disk, (b) recorded so as to be reproduced prior to the video content on the same medium as the disk containing the video content, (c) A method of recording a part of the effective frame of the video content is conceivable.

In the method (a), first, a reference disk on which a reference video signal is recorded is reproduced, a correction parameter is calculated and stored, and when reproducing another disk containing video contents, It is possible to adopt a configuration in which a correction process is performed according to the stored correction parameters. In the method (b), the reference video signal is always reproduced for each disc prior to reproduction, and the correction parameters are automatically calculated.
The video contents included in the same disk may be configured to perform a correction process based on the calculated correction parameters. In the method (c), the reference video signal is transmitted periodically using a part of the effective image frame, and the correction parameter can be corrected every time the reference video signal comes.

A ninth video signal processing device according to the present invention comprises:
Encoded data of the main video signal, (a) position correction amount of video signal, (b) correction amount of gain and DC offset of video signal, (c) tap gain of waveform equalization filter for video signal, ( d) including a reference video signal for determining at least one parameter of an inverse conversion parameter with respect to the converted signal component of the video signal, transmitting or recording the encoded data of the sub video signal accompanying the main video signal. Coded data receiving means, a main video signal decoding means for decoding coded data of the main video signal received by the coded data receiving means, and a sub video signal received by the coded data receiving means. A sub-video signal decoding means for decoding encoded data of the video signal; and a sub-video signal obtained by the sub-video signal decoding means on the main video signal obtained by the main video signal decoding means. Mapping means for mapping, a video signal receiving means for receiving a video signal obtained by mapping a sub-video signal to a main video signal by the mapping means, and a sub-video signal mapped from the video signal received by the video signal receiving means And (a) to (d) using the reference video signal.
And a correction means for correcting the video signal received by the video signal receiving means using the parameters determined by the parameter determination means.

The above-mentioned reference video signal can be transmitted using the effective image area of the video signal. However, as in the ninth video signal processing device, the reference video signal is Can be transmitted. For example, the DVD-Video standard defines a sub-picture signal called a sub-picture. The sub-picture video data is obtained by encoding a bitmap video. Usually, it is for transmitting an image such as a menu screen or a subtitle supermarket.

In the ninth video signal processing apparatus, a reference video signal for video correction processing is transmitted using this sub-picture video. The sub-picture can be controlled to be displayed or hidden without affecting the main video signal. It is easy to control such that the sub-picture is displayed during correction parameter calculation and the sub-picture is not displayed during correction. Can be performed. Further, since the mapping position of the sub-picture to the main video is defined by the pixel precision, even when the video signal carrying the sub-picture is transmitted via an analog transmission path or the like, the position correction of the effective image area, the gain and the like are performed. It is also possible to accurately correct transmission characteristics such as frequency characteristics.

[0050] A tenth video signal processing apparatus according to the present invention is characterized in that the coded data of the main video signal and the coded data of the sub-video signal accompanying the main video signal are transmitted or received via a recording medium. Data receiving means, main video signal decoding means for decoding the encoded data of the main video signal received by the encoded data receiving means, and encoded data of the sub-video signal received by the encoded data receiving means Sub-picture signal decoding means for decoding the sub-picture signal, mapping means for mapping the sub-picture signal obtained by the sub-picture signal decoding means onto the main picture signal obtained by the main picture signal decoding means, and this mapping means A video signal receiving means for receiving a video signal in which a sub video signal is mapped to a main video signal, and a video signal receiving means for decoding the video signal received by the video signal receiving means. And a descrambling processing unit that performs the rumble processing.

The scrambling process is performed on the main video signal or the encoded data of the main video signal, and the scrambling process on the main video signal or the encoded data of the main video signal is performed on the sub video signal or the encoded data of the sub video signal. A scramble process equivalent to the scramble process is performed in synchronization. In this case, it is preferable that the equivalent scrambling process synchronized with the main video signal is not performed on the sub video signal including the reference video signal among the sub video signals.

Here, if the main video signal has been scrambled and the sub-picture video is non-scrambled or scrambled independently of the main video signal, the data on the receiving side is In the scrambling, it is necessary to perform descrambling processing on the main video and the sub-picture independently, and then map the sub-picture on the main video.

In the ninth video signal processing apparatus, the sub-pictures are mapped on the receiving side by performing equivalent scrambling in advance in synchronization with the scrambling of the main video signal. By performing the descrambling process on the video signal, it becomes possible to reproduce the video.

If the ninth video signal processing device has scrambled the sub-picture itself, the ninth video signal processing device converts the reference video signal from the video signal before descrambling. Extract
It becomes difficult to perform correction processing on the video signal before descrambling. On the other hand, according to the tenth video signal processing device, the sub-picture including the reference video signal is not subjected to the scrambling process, and if the original sub-picture video is not the reference video signal, the sub-picture is equivalent to the main video. By extracting the reference video signal mapped as a sub-picture from the video signal before descrambling by applying a configuration that performs a scramble, a correction process for the video signal before descrambling is performed using the extracted reference video signal. Can be performed.

[0055]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows a system configuration according to a first embodiment of the present invention. In FIG. 1, video data encoded by, for example, the MPEG2 method is input as an input signal 20 on the transmission side, and is decoded by a video decoder 10. The digital video signal 21 output from the video decoder 10 is converted into an analog video signal 22 by the D / A converter 11, transmitted through an analog transmission path, and received by the video signal receiving device 1. The video signal receiving device 1 includes an A / D converter 12, a video signal correction unit 1,
3. Digital signal processing unit 14 and D / A converter 15
Consists of

That is, the analog video signal 22 is A / D
After being re-sampled and digitized by the converter 12, it is input to the video signal correction unit 13 and corrected.
The video signal correction unit 13 will be described later in detail. The corrected digital video signal 24 output from the video signal correction unit 13 is subjected to various processes by the digital signal processing unit 14. Digital signal processing unit 14
Is a descrambling process of a scrambled video signal, for example. The digital video signal 27 output from the digital signal processing unit 14 is
It is output as it is, or is D / A converted again by the D / A converter 15 and output as an analog video signal 26.

Hereinafter, referring to FIGS. 2 to 11, the video signal correction unit 13 for the video signal resampled and digitized by the A / D converter 12 in this embodiment will be described.
The details of the correction processing according to will be described in detail. In this embodiment, the video signal correction unit 13 performs three types of correction processing: (a) position correction, (b) gain and DC offset correction, and (c) waveform equalization.

(Regarding Position Correction) Video Decoder 10
In the video signal 21 decoded in the above, the position of the effective image area may be slightly shifted through processing such as D / A conversion and A / D conversion. FIG. 2 is a diagram showing an example of a positional shift of an effective image area. An effective area 31 of a video signal resampled and digitized by the A / D converter 12 with respect to an effective area 30 of an original video signal. Are shifted as shown in the figure. That is, the origin position 31a of the effective region 31 of the resampled video signal is shifted in the horizontal and vertical directions with respect to the origin position 30a of the effective region 30 of the original video signal.

When the position of the effective image area of the video signal is slightly shifted in this way, for example, when the digital signal processing section 14 performs pixel-level digital video signal processing, data at a pixel position different from the originally intended pixel position is obtained. Artifacts may occur due to operation.
In this case, it is necessary to perform a process of automatically detecting a shift of the effective image area and performing position correction, and the position correction process is performed by the video signal correction unit 13.

FIG. 3 shows an example of the reference video signal frame 32 for detecting the positional deviation of the effective image area as shown in FIG. 2 at the time of this position correction. From the left, the pixel values of the data of the M pixels are fixed at “240”, and the pixel values of the other data are fixed at “16”. Here, each pixel value is represented by, for example, 8 bits, and the value is “0” to “255”. Each pixel value after resampling by the A / D converter 12 is defined as Y (v, h). h represents a horizontal pixel position (0 to H), and v represents a vertical line position (0 to V). Using the reference video signal shown in FIG. 3, the amount of deviation (dv, dh) of the origin position is estimated as shown in Expression (1),
Using this as the position correction amount, the position of the effective image area can be corrected. Y '(v, h) represents the video signal after the position correction.

[0061]

(Equation 1) These position corrections are performed only on a specific signal component (for example, a luminance signal) of the video signal, and for other signal components (for example, a color difference signal) of the video signal, the position correction amounts (dv,
dh) may be used after being scaled according to the sampling ratio. Alternatively, as shown in FIG. 4, a reference video signal frame is independently defined for each signal component, and the position correction amount is detected independently. It may be. In FIG. 4, 4:
2: 0 component signal (Y, Cb, C
r) and the reference video signal frame 40 for the luminance signal (Y) of the video signal composed of the color difference signals (Cb, C).
3 shows reference video signal frames 41 and 42 for r).

As the reference video signal shown in FIG. 3 or FIG. 4, the signal of the entire frame (screen) is transmitted.
As shown in the figure, the reference video signal 50 is inserted only into the upper N lines of the frame, and the lower part from the (N + 1) th line is set as an effective image area. The configuration may be such that the reference video signal is transmitted by using it.

Here, the shape of the reference video signal frame is not limited to those shown in FIGS. 3 to 5, but in any case, it is constant in a predetermined area unit within the screen, for example, a unit of an integral multiple of the DCT block. It is configured to have a pixel value. That is, in the reference video signal portion, the pixel value in each DCT block is constant. In addition, the reference video signal is encoded as an intra macroblock for which motion compensation prediction is not always performed. As a result, as described below, it is possible to minimize distortion caused by encoding and decoding.

In the MPEG2 system, either an original video signal or a prediction error signal obtained by motion compensation prediction is DCT-transformed for each block (DCT block), and after each DCT coefficient obtained by this is quantized, Variable-length coded. If the pixel value is constant in the block, DC
Although only the DC component is encoded by the T-transformation, the DCT or inverse DCT basis functions for the DC component are all integers, and no decimal error occurs.

In the quantization in the MPEG2 system, only the DC component of the DCT coefficients of the intra macroblock is encoded without being affected by the quantization. In other words, image data having a fixed pixel value in a DCT block can be encoded losslessly by encoding it in an intra macroblock.
Even through the decoding system, the pixel values are preserved.
Therefore, it is possible to easily transmit the reference video signal whose signal value is known. DCT in MPEG2 system
The block size is 8 × 8 pixels, and N and M are shown in FIG.
In the example shown in FIG. 4, a multiple of 8, and in the example shown in FIG.
May be a multiple of.

(Regarding Gain and DC Offset Correction) Digital video signal 21 input to D / A converter 11
The pixel data having pixel values “0” to “255” in
It is desirable that the digital video signal 23 after resampling by the A / D converter 12 is also received as a pixel value of “0” to “255”. However, actually D / A
The input of the D / A converter 11 and the output of the A / D converter 12 are affected by the characteristics of the A / D converter 12 and the analog transmission path for transmitting the analog video signal 22 output from the converter 11. In some cases, the gain of the transmission path up to this point does not become 1, and a DC offset may be added in the transmission path.

FIG. 6 shows ideal transmission characteristics.
The horizontal axis indicates the transmission pixel value, and the vertical axis indicates the reception pixel value. On the other hand, FIGS. 7 to 10 show examples of transmission characteristics in the case where a shift in gain or DC offset occurs in a transmission path. Here, the broken line shows the ideal transmission characteristics in FIG. 6, and the solid line shows the relationship between the original transmission pixel value and the received pixel value actually measured after resampling.

Such a shift between the gain and the DC offset can be easily measured by transmitting the above-mentioned known reference video signal. That is, if this reference video signal is used, the influence of encoding and decoding can be easily eliminated, and the transmission path from the input side of the D / A converter 11 to the output of the A / D converter 12 can be purely removed. It is possible to measure transmission characteristics. Hereinafter, an example in which the transmission characteristics are corrected from the transmission characteristics measured by transmitting a known reference video signal will be described with reference to the cases of FIGS.

FIGS. 7 and 8 show a case where the gain characteristic of the transmission path is corrected by approximating it with a linear function. Let the transmission pixel value be Y and the reception pixel value be Y ', and approximate to Y' = aY + b. When this equation is solved for Y, it is replaced as in equation (2). Y = (Y′−b) / a (2) In the example of FIG. 7, using a reference video signal having two different pixel values, the equation (2) is obtained from the pixel value of the actually measured value of the reference video signal.
Then, a and b are obtained, and the gain of the video signal received thereafter is corrected. In the example of FIG. 8, the values of a and b are determined by using the least square method from the pixel values of the actually measured values of the reference video signal using the reference video signal of more pixel values, and received after that. Video signal gain correction.

When the transmission path has a non-linear gain characteristic as shown in FIG. 9, a reference video signal having a plurality of pixel values is used, and the pixel value “0” is calculated from the pixel value of the measured value of the reference video signal. A conversion table G (k) for "-" to "255" is created. The conversion value for a pixel value not included in the reference video signal is a value interpolated from the conversion value in the vicinity. The video signals received thereafter are subjected to pixel value conversion of each pixel according to the created conversion table G (k). Equation (3)
FIG. 7 shows an example of pixel value conversion using the conversion table G (k).

G (k): k = 0, 1,..., 255, 0 ≦ G (k) ≦ 255 When k is included in the reference video signal: G (k) = R (k) R (k) is When the measured value k for the reference video signal value k is not included in the reference video signal: G (k) = Ak + B A = {R (k ′) − R (k ″)} / (k′−k ″) B = R (k ')-Ak' k 'and k "are reference video signal values near k Y = G (Y'): Y 'is a received pixel value, Y is a converted pixel value (3) FIG. An example of a pixel value correction by a first-order approximation to a color difference signal is shown in Fig. 10. A color difference signal of a sampled YCbCr signal is normally represented by a signed integer represented by a zero level of "128", that is, a two's complement. Since the shift of the zero level greatly affects the image, “128” is added to the pixel value of the reference image for the color difference signal, and the equation (4) is obtained.
The conversion formula is determined as shown in FIG.

C = Ac (C′−R (128)) + 128 C ′ is the pixel value of the received color difference signal R (128) is the actual measurement value for the reference video signal value “128” Ac is the reference video signal and its actual measurement value (4) Next, a waveform equalizing filter according to an embodiment of the present invention, which aims to remove the effects of ringing or the like generated by a shift in the resampling phase or an echo generated in the transmission path. explain.

FIG. 11 shows a configuration example of the waveform equalization filter. The waveform equalization filter of FIG. 11 is a transversal type adaptive filter, and is generally used as a waveform equalizer. This filter resamples the analog transmitted video signal 63 by the A / D converter 61, and performs digital filtering on the resampled digital video signal 64 by the transversal filter 60. The configuration of FIG.
It implements a learning algorithm called an S (Least Mean Square) algorithm, and compares a value of an output signal 66 of an N-1 tap transversal filter 60 with an expected value 65 with respect to a known reference signal. , the amount of error is fed back through the switch 62 performs learning by successively modifying the values of C ₀ ~C _N-1 of the respective tap coefficients. The feedback amount is determined by the parameter μ, and the speed of convergence is controlled by the value of μ. When the learning of the tap coefficients converges, the switch 62 turns off the feedback of the error amount, and filters the input digital image signal 64 using the determined tap coefficients, thereby performing waveform equalization.

It is effective to use a signal having a wide frequency band as a reference signal for learning the adaptive filter. For example, in the MUSE method using the sample value analog transmission method of HDTV, an impulse waveform (impulse-shaped pixel sample) is transmitted as a reference signal during a video blanking period, and learning of an adaptive filter for waveform equalization on the receiving side is performed. How to do is taken. However, since the impulse waveform is greatly affected by the encoding itself when encoding such as MPEG2, it is not suitable for the waveform equalization of the transmission path in the present embodiment.

On the other hand, in the present embodiment, the DC
By using a reference video signal composed of a T block or a multiple block thereof, an arbitrary step waveform can be generated without being affected by encoding / decoding by the MPEG2 system. Since the step waveform has a wide frequency band similarly to the impulse waveform, it is as effective as the impulse waveform as a reference signal for waveform equalization of the transmission path.

By using the above-described adaptive filter for waveform equalization and learning of the adaptive filter using the step waveform, it is possible to reduce the distortion of the video signal due to the effects of analog transmission and resampling. The adaptive filter for waveform equalization can be independently implemented and controlled for each video signal component such as luminance / color difference. Further, by performing adaptive filter learning and equalization processing independently for each video signal component, it becomes possible to effectively correct differences in transmission characteristics for each video signal.

(Second Embodiment) FIG. 12 is a block diagram showing a system configuration example according to a second embodiment of the present invention. This embodiment is an extension of the first embodiment. 12, the same components as those in FIG. 1 are denoted by the same reference numerals, detailed description thereof will be omitted, and differences from the first embodiment will be mainly described.

This embodiment is different from the first embodiment in that a video signal format converter 70 is added to the transmitting side, and a video signal format inverse converter 71 and a second video That is, a signal correction unit 72 and a video signal format conversion unit 73 are added. In the MPEG-2 video standard, the format of a video signal to be encoded is defined as a 4: 2: 0 component signal in a main profile widely used in particular. On the other hand, it is difficult to directly connect 4: 2: 0 signals in a video signal format of a conventional video device, and usually, the video signal format is converted after decoding.

Video signal format converter 70 and D
The format conversion performed using the / A converter 11 is as follows.
The conversion is from 4: 2: 0 signals to 4: 2: 2 signals (YCbCr component signals), S-video signals, composite video signals, and the like. 4: 2: 2 signal, S-video signal,
Each of the composite video signals is composed of luminance and two color difference signals.

However, these signals are 1 in luminance and color difference.
The number of lines of the color difference signal is twice that of 4: 2: 0, in which the number of lines per frame is the same and the number of lines of the color difference signal is half the number of lines of the luminance signal. Further, the S video signal and the composite video signal are subjected to orthogonal transformation and band limitation of the color difference signals Cb and Cr, and
And Q are converted to two axes. The S video signal is transmitted as two independent analog signals of a luminance signal Y and a chrominance signal C obtained by multiplexing I and Q. Further, in the composite video signal, the color signal C is changed to the luminance signal Y.
Are transmitted as a single analog signal multiplexed on the same line.

Here, 4: encoded by MPEG2:
When it is necessary to perform digital video signal processing in units of pixel samples of the 2: 0 signal, the received analog video signal 22 is subjected to resampling by the A / D converter 12 and inverse conversion of the video signal format. There is a need. In the present embodiment, the video signal format inverse converter 71 corrects the video signal resampled by the A / D converter 12 by the first video signal corrector 13 for canceling the influence of the transmission path. After being done,
The inverse conversion of the video signal format is performed. Also,
The video signal 75 after the inverse conversion of the video signal format by the video signal inverse conversion unit 71 can be subjected to the pixel value correction processing by the second video signal correction unit 72.

In this embodiment, the first video signal correction unit 1
3, a video signal format inversely converted by the video signal format inverse conversion unit 71, and a video signal 76 that has been subjected to the pixel value correction process after the format inverse conversion by the second video signal correction unit 72. for,
After the digital video signal processing unit 14 corrects the signal at the 4: 2: 0 signal level originally encoded by MPEG2, the video signal format conversion unit 73 converts it to a desired video format and outputs it again. Has become. The video signal 77 output from the video signal format converter 73 is output as it is as the digital video signal 27, or the D / A converter 15
/ A conversion and output as an analog video signal 26. Hereinafter, the inverse conversion of the video signal format by the video signal focus inverse conversion unit 71 will be specifically described.

As described above, a general video signal is converted to MP
In order to return to the 4: 2: 0 signal of EG2, vertical line subsampling of the color difference signal is required. FIG.
Shows an inverse converter 80 that performs an inverse conversion of the video signal format from the 4: 2: 2 signal to the 4: 2: 0 signal.
A luminance signal (Y signal) 83 and two color difference signals (Cb and Cr signals) 84 and 85 are input as 4: 2: 2 signals, and a luminance signal (Y signal) 86 is obtained as a 4: 2: 0 signal after inverse conversion.
And two color difference signals (Cb and Cr signals) 87 and 88 are output. The conversion from the 4: 2: 2 signal to the 4: 2: 0 signal may be performed by performing vertical line subsampling on the Cb signal and the Cr signal independently by the vertical adaptive line subsamplers 81 and 82. The Y signal 83 is delayed by the delay circuit 89 by the processing delay amount in the line subsamplers 81 and 82, and is extracted as a Y signal 86.

Here, the adaptive line subsamplers 81, 8
Prior to the description of the second embodiment, the spatial and temporal phase relationship between the pixels of the 4: 2: 0 signal and the 4: 2: 2 signal specified by MPEG2 will be described first. FIGS. 14 and 15 show the phase relationship between the luminance signal sample “x” and the color difference signal sample “サ ン プ ル” in the frame for the 4: 2: 0 signal and the 4: 2: 2 signal, respectively. The horizontal axis represents the horizontal direction in the frame, and the vertical axis represents the vertical direction in the frame.

FIGS. 16 and 17 also show 4: 2: 0
The phase relations of the luminance signal sample “x” and the color difference signal sample “の” of the signal and the 4: 2: 2 signal in the time direction and the vertical direction in the frame or field are shown. In FIGS. 16 and 17, (a)
Indicates the field of the interlaced image, and (b) indicates the phase relationship between the luminance signal and the color difference signal in the frame of the non-interlaced image.

In FIG. 12, the MPEG2 decoder 10
The video signal decoded as a 4: 2: 0 signal 21 by the video signal format conversion section 70 is 4: 2: 2.
It is converted to a signal 74. Here, in the video signal format converter 70, the color difference signal is twice over-sampled in the vertical direction according to the phase relationships shown in FIGS. By estimating the configuration of this oversampling filter, the 4: 2: 0 signal 21 decoded by the MPEG2 decoder 10 can be reconstructed. In this case, the tap coefficients of the oversampling filter are estimated using the reference video signal, and the tap coefficients of the inverse filter are calculated based on the estimated tap coefficients, so that 4: 2: 2 is used using another filter. Inverse conversion to the 4: 2: 0 signal 21 can be performed more accurately than when downsampling the signal to a 4: 2: 0 signal is performed.

For example, it is assumed that the video format converter 70 shown in FIG. 12 performs color difference signal conversion from 4: 2: 0 to 4: 2: 2 on a field basis using an N-tap FIR filter. This is, for example, to convert the color difference signal sample “○” in FIG. 16A into the color difference signal sample “○” in FIG. 17A on a field basis. For example, when N = 2, 1: 7 from the color difference signal samples of two lines adjacent to each other in the top field.
And 5: 3 for linear interpolation, and for the bottom field, similarly for 3: 5 and 7: 1. Equation (5) shows the state of this linear interpolation.

C422 (2v, h) = {a × C420 (v, h) + b × C420 (v-1, h)} / (a + b) C422 (2v + 1, h) = {c × C420 (v, h) h) + d × C420 (v-1, h)｝ / (c + d) (5) Here, C420 (v, h) is the 4: 2: 0 signal of the coordinates of the vertical line position v and the horizontal pixel position h. Color difference signal samples,
C422 (v, h) is a color difference signal sample of the 4: 2: 2 signal after conversion. “a”, “b”, “c”, and “d” are conversion parameters, specifically, interpolation ratios of linear interpolation.

This equation (5) is converted to C420 (v, h) and C420 (v-1, h).
Is solved, the inverse conversion from the 4: 2: 2 signal to the 4: 2: 0 signal is obtained. Normally, the conversion parameters a, b, c, and d are unknown, but a set of a known 4: 2: 0 reference video signal C420 and its actual measured value C422 of the 4: 2: 2 reference video signal is represented by at least the number of tap coefficients. If measured independently for several minutes, the conversion parameters a,
By solving a system of linear equations with b, c, and d as unknowns,
a, b, c, and d can be estimated.

Further, even when the number of taps is unknown, a conversion filter having a number of taps M (M ≧ N) larger than the true number of taps N is assumed, and a necessary number of reference video signals and their actual measurement data are used. By solving the simultaneous equations, it is possible to estimate the tap coefficients.

When the conversion parameters a, b, c, and d from the 4: 2: 0 signal to the 4: 2: 2 signal are obtained in this manner, the conversion parameters a, b, c, and d allow the 4: 2: 2
It is possible to obtain an appropriate reverse conversion parameter from the signal to the 4: 2: 0 signal. Here, the reference video signal for estimating the conversion parameter is a DCT in the color difference signal.
By using a block waveform of a block or a multiple thereof, a waveform in which an arbitrary pixel value is set for each block can be transmitted without being affected by encoding / decoding.

FIG. 18 shows, as an example of the video signal format inverse converter 71 in FIG. 12, the video signal format converter 70 converts the signal converted from the 4: 2: 0 signal into the S video signal again to 4: 2: 0. FIG. 3 is a diagram illustrating a configuration of a video signal format reverse conversion circuit 90 for performing reverse conversion into a signal.

As described above, the S video signal is composed of the luminance signal (Y) and the color difference signals I,
Color signals (C) in which Q is multiplexed are transmitted in parallel. In FIG. 18, a luminance signal 93 is output through a delay circuit 99, and a chrominance signal 94 is converted into an I signal
After being separated into signals, they are converted into color difference signals Cb and Cr by the matrix circuit 92. At this point, the S-video signal is a 4: 2: 2 signal, and the color difference signal C
The b and Cr downsamplers 98a and 98b perform １ ／ downsampling in the vertical direction.
A luminance signal (Y) 95 and two color difference signals (Cb, Cr) 96 and 97 constituting the 4: 2: 2 signal are output.
The inverse conversion parameters of the matrix circuit 92 and the downsamplers 98a and 98b in FIG. 18 can be obtained by inverse calculation from the conversion parameters estimated using a known reference video signal, as in the example of FIG.

FIG. 19 shows another example of the video signal format inverse converter 71 shown in FIG. 12, in which the video signal format converter 70 converts a signal converted from a 4: 2: 0 signal into a composite video signal again into a 4: 2 signal. FIG. 2 is a diagram illustrating a configuration of a video signal format inverse conversion circuit 100 for performing inverse conversion to a: 0 signal.

The composite video signal 104 has a Y / C
After being separated into a luminance signal Y and a chrominance signal C by the separation circuit 102, the delay circuit 109, the separation circuit 101, the matrix circuit 102, and the downsamplers 108a and 108b perform the same processing as the processing on the S video signal shown in FIG. As a result, the signal is converted into a 4: 2: 0 signal. Also in FIG. 19, the estimation of the conversion parameters based on the reference video signal and the calculation of the inverse conversion parameters are performed.

FIG. 20 shows another example of the video signal format inverse converter 71 shown in FIG. 12, in which the video signal format converter 70 converts the signal converted from the 4: 2: 0 signal into the RGB signal again into the 4: 2 signal. FIG. 2 is a diagram showing a configuration of a video signal format conversion circuit 110 for performing reverse conversion to a: 0 signal.

The RGB signals 114, 115, and 116 are converted into 4: 2: 2 YCbCr signals by the matrix circuit 111, and down-samplers 112 and 113 down-sample the color difference signals in the vertical direction. 2: 0 signals 117, 118, 119
Is converted to 20 and FIG. 18 and FIG.
Similarly to the above, the estimation of the conversion parameter based on the reference video signal and the calculation of the inverse conversion parameter are performed.

Next, an embodiment relating to the overlap processing or the interpolation processing of the present invention will be described. FIG.
Indicates a frame subjected to the overlap processing or the interpolation processing of the present invention. A, b and c in FIG.
Indicates the positions of a plurality of continuous macroblocks, and overlap regions or interpolation regions 132 and 133 are provided at the horizontal boundaries. In FIG. 21, an overlap area or interpolation areas 132 and 133 are formed near the boundary between a plurality of continuous macroblocks a and a plurality of continuous macroblocks b. These overlap areas or interpolation areas 13
Nos. 2 and 133 are set at portions where the distortion of the video signal depending on the transmission characteristic is to be suppressed, and the distortion depending on the transmission characteristic is removed from the resampled video data to reconstruct the video signal. I have.

Next, the overlap processing and its video signal reconstruction processing will be described with reference to FIG. 14 in FIG.
0 is a view of the video signal in the frame as viewed in the horizontal direction. Here, a plurality of continuous macroblock areas (sets of macroblocks) a and b to be encoded of this video signal
And c are mapped and encoded at positions 141, 142 and 143 in FIG. By mapping the macroblock to be coded in this manner, the shaded signal portion in FIG. 21 is double coded.

The coded video signal is decoded in the same manner as ordinary coded data, and the decoded video signal is a,
It is transmitted as a continuous waveform in the order of b and c. Upon receiving the transmitted video signal, resampling is performed, and at the end of the macroblock areas a, b, and c, the true boundary line 144 is detected.
And 145, the video signal in the portion outside is discarded, and the waveform of the original video signal 140 is reconstructed.

That is, the video data on the right side of the boundary 144 for the macro block area a, the video data on the left side and the right side of the boundary 145 for the macro block area b, and the left side of the boundary 145 for the macro block area c are discarded, respectively. After removing the discarded portion, the macroblock areas a, b, and c are combined to reconstruct the original video data 140. By performing such processing, the video signals can be transmitted without the macroblock regions a, b, and c being affected by the characteristics of the transmission path, and without being affected by the image signals in other regions. . For example, when focusing on the macroblock area a, the video data near the macroblock area a in contact with the macroblock area b receives an interaction from the video data near the left end of the macroblock area b due to the characteristics of the transmission path.
However, the macro block area a and the macro block area b
By removing the outer halves of the overlapped region with each other, it is possible to remove the part that has undergone the interaction between the regions depending on the characteristics of the transmission line and still reconstruct the original video signal 140. Become.

FIG. 23 shows an example of reducing the interaction caused by the transmission characteristics between the regions by using the interpolation regions. In FIG. 23, reference numeral 150 denotes a video signal viewed in the horizontal direction, and the video signal 150 is divided into regions a ', b',
c ′ are divided into video signals 151, 152 and 153, and further interpolated signals 157 and 158 between the respective areas a ′, b ′ and c ′.
Insert The interpolation signals 157 and 158 are generated by oversampling by zero interpolation at the boundaries and by a low-pass digital filter. Then, the interpolation signals 157, 158
Video signals 154, 15 of areas a, b, c after inserting
5,156 is encoded as a plurality of macroblocks.

On the receiving side, the encoded video data is decoded, and after transmitting the decoded video signal, re-sampling is performed to remove the interpolation signals corresponding to the interpolation areas 157 and 158, and the original signal is removed. The video signal 150 is reconstructed.

As described above, the interpolated signal is inserted into the video signal, encoded and transmitted, and the interpolated area is removed on the receiving side. , Or the effect of the interaction depending on the transmission characteristics between the regions b ′ and c ′ can be eliminated.

As described above, FIG.
The use of the configuration 3 makes it possible to suppress the interaction between the regions depending on the transmission characteristics. With this feature,
For example, when a plurality of different videos are mapped on the same frame, or when blocks are exchanged by scrambling, it is possible to sufficiently suppress the influence of transmission distortion near the boundary.

As shown in FIG. 22 or FIG. 23, a frame to be coded by providing an overlap area or an interpolation area in a screen as a video signal to be coded and a frame to be coded without providing such areas are mixed. In this case, if the frame size of the input video signal is constant, the horizontal sizes of the encoding target frames are different.

In FIG. 24, the input video frame 17
By providing a horizontal overlap area or an interpolation area with respect to 0, the size of the encoded frame 171 is expanded in the horizontal direction as shown in the figure. On the other hand, considering that a video frame without an overlap area or an interpolation area is mapped to a frame having the same size as the encoded frame 171 and is coded, for example, as shown at 172 in FIG. A non-data area 173 is generated. In this case, using the non-data area 173,
Additional data related to an input video signal can be mapped onto an encoded video signal and transmitted. In other words, when a frame in which an overlap area or an interpolation area exists and a frame in which an overlap area or an interpolation area does not exist are mixed and encoded, additional data is not mapped in the former frame, and It is configured to map the additional data only on the video signal on the frame.

Here, as the additional data, a reference video signal composed of the above-described block waveform can be transmitted. FIG. 25 shows the non-data area 1 in FIG.
73 shows an example in which a reference video signal having a block waveform is mapped. In FIG. 25, a portion 182 is an original video signal, and a portion 181 is a reference video signal mapped to a non-data area.

It is also possible to map data indicating a frame attribute as additional data. As the frame attribute, the coded picture type (I frame, P frame
(Frame, B frame), bit rate, average quantization step size, encoding parameters in MPEG2 encoding such as frame code amount, copyright holder information of contents, copy restriction information such as copy prohibition / copy unrestriction possible / copy number limit And copy generation management information indicating the current number of copies, data such as a content classification code and characters, and, if the video signal is scrambled, information related to a scramble key.

FIG. 26 is a block diagram showing a configuration of a video signal processing device 190 which performs additional data detection and mask processing on a video signal on which such additional data is mapped. The video signal processing device 190 receives as input a video signal 197 obtained by decoding encoded data of a video signal to which additional data has been mapped. Video signal 1
Reference numeral 97 denotes a video signal 200 of a frame provided with the overlap area or the interpolation area and having no additional data by the selector 191 and a video signal 202 of a frame to which the additional data is mapped.
00 is sent to the frame reconstruction unit 192, and the latter video signal 202 is further sent to the selector 194.

The frame reconstructing section 192 removes the overlap area or the interpolation area as described with reference to FIG. 22 or FIG. 23, and outputs the reconstructed frame video signal 201 to the video multiplexing section 193. On the other hand, if the input video signal 202 is the additional data area, the selector 194 sends the video signal 204 to the additional data detector 195. The additional data detector 195 detects additional data from the video signal 204 and outputs additional data 198. If the input video signal 202 is a video area, the selector 194 sends the video signal 203 to the video multiplexing unit 196.

The video multiplexing section 196 outputs a video signal 206 obtained by subjecting the additional data area to masking with the black video signal 205. From the video multiplexing unit 193, the video signal 201 of the reconstructed video frame and the video signal 206 of the frame with the additional data masked are appropriately switched and output as the output video signal 199.

FIG. 27 shows a frame 210 in which the black data is masked in the additional data area for the video frame to which the additional data in FIG. 25 is mapped, and an additional data area for the masked frame 210. A frame 213 in which the origin position corresponding to the width of 211 has been corrected is shown. From the video multiplexing unit 196 in FIG.
The signal 213 in FIG. 27 is output.

(Third Embodiment) FIG. 28 is a block diagram showing an example of a system configuration according to a third embodiment of the present invention. This embodiment is a special case of the second embodiment. 28, the same components as those in FIG. 12 are denoted by the same reference numerals, detailed description thereof will be omitted, and differences from the first embodiment will be mainly described.

This embodiment is different from the second embodiment in that the video signal receiving apparatus 3 corresponds to the digital video processing section 14 in FIG. 12 and is a video signal descrambling processing section 220. That is, a means for inputting the descramble key 221 from outside is added.

In the present embodiment, the video data 20 input on the transmission side has been scrambled. A digital video signal 21 obtained by decoding the video data 20 by the video decoder 10 is resampled by the D / A converter 11 and converted into an analog video signal 22, and then transmitted via an analog transmission path. Then, in the video signal receiving device 3, the received video signal 22 passes through the A / D converter 12 and the video signal correction unit 13, and is inversely converted into the MPEG2 encoded 4: 2: 0 signal by the video signal format inverse conversion unit 71. The descramble processing section 220 performs descrambling processing on the decoded video signal 76, and outputs the video signal 77 again through the video signal format conversion section 73 after the descrambling processing. Video signal 77 output from video signal format converter 73
Is output as it is as the digital video signal 27 or the D / A converter 15
, D / A-converted again and output as an analog video signal 26. Hereinafter, a specific method of the scrambling process performed on the video signal in the present embodiment will be described.

FIG. 29 shows an example of scrambling by exchanging pixel values in units of macroblocks in the horizontal direction in a frame. .. In FIG. 29 indicate the macroblock numbers in the frame, and FIG. 29A shows the macroblock positions before scrambling. Here, FIG. 29B shows a scrambled video in which pixel values are exchanged in the horizontal direction in units of four continuous macroblocks. In FIG. 29 (b), assuming that four consecutive macroblock areas are scrambled units, scrambling is performed by randomly rearranging the arrangement for every three consecutive scrambled units. Here, a parameter that determines a method of generating a random replacement pattern is a scramble key.

The video signal after the scramble processing shown in FIG. 29 (b) is converted into an analog video signal by the D / A converter 11 after being decoded by the decoder 10, and transmitted via an analog transmission path. Considering the case where the signal is re-sampled by the / D converter 12 and further descrambled by the descrambling processing unit 220 via the video signal correction unit 13 and the video signal format inverse conversion unit 71, the characteristic depends on the transmission characteristics. In some cases, fatal artifacts may occur in the video signal 25 after the descrambling process. As the artifacts, for example, (a) deviation of the origin position of the frame, (b) ringing generated at the boundary of the scramble processing unit, and (c) distortion generated at the vertical macroblock boundary are considered. Regarding (b), the influence of the phase shift and jitter of the resampling clock used in the A / D converter 12, the axis conversion of the color difference signal, the band limiting filter, and the like are factors. Also, as for (c), the color difference signal filter (4: 2: 0 to another video signal) is applied to the decoder output signal of the video data whose macroblock positions have been exchanged over uncorrelated lines. Conversion), a large distortion occurs in the video signal 25 after the descrambling process.

However, according to the present embodiment, in the configuration shown in FIG. 28, in the video signal correction units 13 and 72, (1) position correction, (2) gain and Correction of DC offset, (3) Reduction of ringing by waveform equalization by adaptive filter,
(4) Perform each process such as format inverse conversion by estimating format conversion parameters and (5) overlap or interpolation near the boundary of the scramble unit before descrambling by the descramble processing unit 220 as necessary. Accordingly, it is possible to sufficiently suppress the above-described artifact in the video signal 25 after the descrambling process.

FIGS. 30 and 31 are diagrams showing examples of another scrambling method. FIG. 30 shows an example in which pixel values are exchanged in the frame in the vertical direction in units of slices, which are sets of macroblocks in the horizontal direction.
.. Indicate slice numbers, (a) shows a video frame before scrambling, and (b) shows a slice position in a video frame after scrambling. In the example of FIG. 30, random replacement is performed for every three consecutive slices.

FIG. 31 shows a combination of the replacement of macroblocks in the horizontal direction shown in FIG. 29 and the replacement of slices in the vertical direction shown in FIG. 30. Similarly, FIG. 31A shows a video frame before scrambling, and FIG. ) Indicates the slice position in the video frame after scrambling. FIG.
In this configuration, the number of macroblocks serving as a scrambling unit in the horizontal direction itself changes randomly.

In scrambling by exchanging pixel values with a macroblock or slice as a unit as shown in FIG. 30 or FIG. 31, decoding, transmission,
If the processing is performed in the order of resampling and descrambling, artifacts depending on the transmission characteristics will largely occur in the video signal after descrambling. But,
Also in this case, the video signal after resampling by the A / D converter 12 in the configuration shown in FIG.
By performing the processes (1) to (5), these artifacts can be sufficiently removed.

FIG. 32 is a diagram for explaining still another example of the scrambling method. In FIG. 32, descrambling is performed for scramble in which the polarity inversion processing is independently performed on the luminance signal Y and the color difference signals Cb and Cr. Part 260
Is shown. In this example of scrambling,
The scrambling is performed by dynamically and independently changing whether or not the polarity of the luminance signal Y and the color difference signals Cb and Cr is inverted for each signal component. Therefore, the parameter for generating the time change pattern of the polarity inversion is a scramble key.

In FIG. 32, input signals 267, 26
8, 269 are a Y signal, a Cb signal, and a Cr signal, respectively, and their polarities are inverted by polarity inverters 261, 262, 263, respectively. The selectors 264, 265, and 266 independently control the signals whose polarity is inverted by the polarity inverters 261, 262, and 263 and the signals 267, 268, and 269 that are not inverted by the control signals 270, 271, and 272 for each signal component. And output signals 273, 274, 27
Output as 5.

If the video data subjected to the scramble processing based on the presence / absence of the polarity inversion is processed in the order of decoding, transmission, resampling, and descrambling as in the example of FIG. Artifacts depending on the characteristics will largely occur in the video signal after descrambling. In particular, deviations in gain and DC offset will cause severe artifacts.
In this case, as shown in Expression (6), the signal Inv (Y) obtained by inverting the polarity of the signal Y can be returned to the signal Y by further inverting the polarity. However, when the gain of the transmission path is a and the DC offset b is added, a signal Y ′ obtained by reversing the polarity of the signal transmitted with the polarity inverted and a signal Y ″ transmitted without the polarity reversal are obtained. Each time the polarity is inverted, the characteristics of the descrambled video signal change, resulting in a very visually unsightly video.

Y = Inv (Inv (Y)) Y ′ = Inv (a × Inv (Y) + b) Y ″ = aY + b Y ′ ≠ Y ″ (6) However, according to the present invention, the reference video signal is used. By performing the descrambling process after performing the correction of the gain and DC offset that were applied to the signal after resampling,
The above artifacts can be removed.

FIG. 33 shows another example of the scrambling method. The scrambling shown in FIG. 33 focuses on a two-dimensional color difference signal and performs scrambling by orthogonal transformation of the color difference signal. Equation (7) shows the conversion equation.

[0128]

(Equation 2) FIG. 33 shows the replacement or rotation of the color difference signal axes. FIG. 33A shows scrambling by exchanging the Cb signal and the Cr signal, and is a case where the conversion coefficients in equation (7) are a = 0, b = 1, c = 1, and d = 0. FIG. 33B shows a case where the axes of Cb and Cr are rotated by + θ, and scramble is performed by changing the conversion coefficient of Expression (7) with time. Here, a parameter for generating a change pattern of the conversion coefficient is a scramble key. In both scramble and descramble, the operation of equation (7) is performed, but the transform coefficients have inverse matrix relationships.

FIG. 34 is a block diagram showing a scramble processing section or descrambling processing section for performing scrambling shown in equation (7). This scramble processing unit or descrambling processing unit 280 is a matrix circuit 2 that performs an operation using transform coefficients a, b, c, and d.
81, and Y as input signals 282, 283, and 284.
Signal, Cb signal and Cr signal are input, and output signal 28
5, 286, 287, scrambled or descrambled Y signal, Cb signal, C signal
Outputs r signal.

Here, if processing is performed in the order of decoding, transmission, resampling, and descrambling, as in the example of FIG. 29, artifacts depending on the transmission characteristics may occur greatly in the descrambled video signal. become. In particular,
Since the descrambling processing unit receives an interaction between signal components by the calculation of Expression (7), a difference in transmission characteristics between signal components causes a fatal artifact to occur in the descrambled video data. However, by performing the above-described processes (1) to (5) for each signal component on the data before descrambling after resampling according to the present invention, these artifacts can be sufficiently removed. Becomes

FIG. 35 shows that, in the scrambling method shown in FIGS. 29 to 31, scrambling by exchanging macroblocks is not performed in a region of a predetermined width in units of blocks or macroblocks at the outermost peripheral portion of the screen. Is shown. Out of the frames 290 subjected to scrambling by exchanging macroblocks shown in FIG.
Is not scrambled for replacing macroblocks,
Only the shaded area 292 in the drawing is scrambled by replacing macroblocks.

As shown in FIG. 2, when the origin position of the video frame is shifted depending on the transmission characteristics, some effective pixel data in the outer peripheral portion may be lost. In this case, when the pixel data of the macroblock is replaced at all macroblock positions in the effective image area, a pixel area which is not reconstructed even in the descrambling inside the video frame due to the lack of the effective pixel data described above. appear.

However, by separating the scrambled area 291 from the non-scrambled area 292 as shown in FIG. 35, it is possible to limit the loss of the effective pixel data to the non-scrambled area, and the pixel within the descrambled image is It is possible to prevent data from being lost.

(Fourth Embodiment) FIG. 36 is a block diagram showing a system configuration example according to a fourth embodiment of the present invention. This embodiment is an extension of the third embodiment. 36, the same components as those of FIG. 28 are denoted by the same reference numerals, detailed description thereof will be omitted, and description will be made focusing on differences from the third embodiment.

The difference between this embodiment and the third embodiment is that
A scramble key information detector 23 is provided in the video signal receiver 4.
0 and a scramble key generation unit 233 are added. In the present embodiment, the video signal 22 input to the video signal receiving device 4 is scrambled, and the first information related to the scramble key is mapped using a part of the effective image signal area on the video signal. ing.
Then, the first information 231 related to the scramble key is extracted by the scramble key information detection unit 230.

Further, the scramble key 234 is generated by the scramble key generation unit 233 from the second information 232 related to the scramble key input from the outside and the first information 231 related to the scramble key extracted from the video signal. Then, the video signal is descrambled by the descrambler 220.

Second information 2 related to the scramble key
32 is, for example, fixed information for each video title.
It is input via a C card or the Internet. Also, the first information 231 related to the scramble key is:
It is dynamically changing scramble key difference information. By combining these two information 231, 232,
A dynamically changing scramble key can be reconstructed. Here, by providing the second information 232 related to the scramble key for a fee, it is possible to configure an individual charging system for video signals.

(Fifth Embodiment) FIG. 37 is a block diagram showing an example of a system configuration according to a fifth embodiment of the present invention. This embodiment is a system to which the first embodiment is applied. The video data input to the decoder 10 is recorded on the optical disk 302 and is reproduced by the optical disk drive device 301. Decoded video signal 2
1 is converted into an analog video signal 22 by the D / A converter 11 and transmitted via an analog transmission path.

In the video signal receiving device 5, the received analog video signal 22 is resampled and digitized by the A / D converter 12, and the digital video signal 23 is corrected by the video signal correction unit 13. After the digital video signal processing by the digital signal processing unit 14, the analog signal is returned to the D / A converter 15 and output. The output analog video signal 26 is supplied to the display device 305 and displayed as a video.

Here, the optical disk 302 is a DVD-Vi
optical disk drive 301
And a part 300 of the decoder 300 and the D / A converter 11
Can be assumed to be a conventional DVD video player. Further, the A / D converter 12, the video signal correction unit 1
3. The video signal receiving device 5 including the digital signal processing unit 14, the D / A converter 15, and the data memory 303 to be described later is an external adapter.
0, the video signal 22 output from the
6 is output.

In the system shown in FIG. 37, DVD-Vi
Video signals recorded on an optical disk 303 which is a video disk (DVD video disk) are shown in FIGS.
The digital video signal processing unit 14 of the adapter 5 has performed the scramble processing described in FIG. An external descramble key is set to the adapter 5 via the line 304. The line 304 is connected to an IC card or the Internet, and charging can be performed by charging the descramble key for a fee. That is, by using the scrambling of the video signal, a DVD video system (more generally, a chargeable DVD control system can be controlled by a combination of the conventional DVD player 300 and the external adapter 5 in the framework of the conventional DVD video standard. Digital video system).

However, in FIG. 37, the DVD player 300
Is transmitted to the adapter 5 via the analog transmission path and then re-sampled to perform the descrambling process.
Depending on the characteristics of the analog transmission path, artifacts may occur in the descrambled video signal. However, as described above, based on the present invention, the correction parameter is calculated using the reference signal, and the correction processing is performed by the video signal correction unit 13, so that the artifact depending on the characteristics of the analog transmission path is sufficiently reduced. It becomes possible.

In the system shown in FIG. 37, once each device is installed, the analog transmission characteristics there are almost uniquely determined. Therefore, the data memory 3 is stored inside the adapter 5.
03 is prepared, the correction parameter using the reference video signal is calculated only once, and the obtained correction parameter is stored in the data memory 303.

If the correction parameters are set in this way, it is not necessary to calculate the correction parameters based on the reference video signal every time in the same system environment.
It is also possible to adopt a configuration in which the correction parameters recorded in the data memory 303 are read out every time the DVD video is reproduced, and the correction processing for the video signal is performed.

Next, an example of the operation of the digital video system according to this embodiment will be described with reference to the flowcharts shown in FIGS. FIG. 38 is an operation flow in the case where the reference video signal for calculating the correction parameter described above is supplied as an independent optical disk (referred to as a reference disk). In this operation example, when the adapter 5 is connected to the DVD player 300 and the reproduction from the DVD video disc 302 is started, first, whether or not the correction parameters recorded in the data memory 303 in the adapter 5 are initialized Is determined (step S10), and if not initialized, the user is requested to reproduce the reference disk on which the reference video signal is recorded (step S11).
Then, when the user reproduces the reference video signal from the reference disk (Step S12), the necessary correction parameters are calculated by the video signal correction unit 13 (Step S13), and the calculated correction parameters are recorded in the data memory 303. (Step S14). Thereafter, the process returns to step S10.

On the other hand, if the correction parameters have been initialized in step S10, when the data is reproduced from the DVD-Video disc 302 containing the coded data of the scrambled video signal, the correction recorded in the data memory 303 is performed. The parameters are read (step S15),
Based on this, a correction process is sequentially performed on the input video signal (step S16), and a digital signal process (descrambling process) is performed on the corrected video signal (step S18). Then, the processing of steps S16 to S18 is repeated until it is determined in step S19 that the reproduction from the DVD video disk 302 has been completed.

FIG. 39 shows that the reference video signal for calculating the correction parameter is recorded on the same medium as the disk on which the coded data of the scrambled video signal is recorded. 9 shows an operation flow when a reference video signal is reproduced. In this operation example, the reference video signal is automatically reproduced each time the disc is replaced and reproduced (step S20), the correction parameter of the adapter 5 is calculated (step S21), and the correction parameter is set (step S21). S22). next,
The reproduction of the video signal (video content) on the same disk is started (step S23), the video signal is sequentially corrected (step S24), and the corrected video signal is subjected to digital signal processing. (Descramble processing) is performed (step S25). Then, in step S26, the DVD-Video disc 30
Until it is determined that the reproduction from step 2 has been completed, step S
The processing of 23 to S25 is repeated.

FIG. 40 shows an operation flow in a system in which a reference video signal for calculating a correction parameter is transmitted using a part of an effective image area in a video signal frame. In this operation example, when the video is reproduced from the disc (step S30), and the video frame in which the reference video signal is mapped to a part of the effective image area of the reproduced video signal is detected in step S31, the reference video signal is detected. (Step S32), and the correction parameter is calculated (Step S33). Based on this, the correction parameter up to the previous time is updated (Step S3).
4). Thereafter, the reproduced video signal is sequentially subjected to correction processing using the updated correction parameters (step S35), and further, digital signal processing (descrambling processing) of the corrected video signal is performed. (Step S36). Steps S30 to S30 are performed until it is determined in step S37 that the reproduction from the disc has been completed.
The process of S36 is repeated.

In the system based on the operation flow of FIG. 40, each time a video frame to which the reference video signal is mapped is detected, the detection of the reference video signal and the update of the correction parameter are sequentially performed. It is possible to follow a change in the transmission characteristic that fluctuates.

(Sixth Embodiment) Next, as a sixth embodiment of the present invention, a reference video signal for calculating a correction parameter using a sub-video signal instead of a main video signal using FIGS. A description will be given of a system for transmitting data by using.

In the DVD video standard, sub-picture data called sub-pictures is defined in addition to main picture data encoded by MPEG2. The sub-picture is obtained by encoding bitmap data, and the encoded data of the main video and the encoded data of the sub-picture are packet-multiplexed and recorded on the optical disc. The video of the sub-picture is overlaid at a predetermined position on the effective image area of the main video signal decoded inside the DVD player, and the video signal on which the sub-picture is overlaid is output from the DVD player.

FIG. 41 shows an example of mapping between sub-pictures and main video frames. Main video frame 311 and sub-picture data 310 as a reference video signal
Are independently encoded and packet-multiplexed.
Each of the encoded data is decoded by the decoder, and FIG.
As shown at 312, the sub-picture video is mapped to a predetermined position on the main video frame and output.

FIG. 42 is a block diagram showing an example of a system configuration according to the sixth embodiment of the present invention, in which a video signal correction parameter is determined for a sub-picture signal such as a DVD-standard sub-picture. For mapping and transmitting the reference video signal. In FIG.
The data 320 obtained by packet-multiplexing the encoded sub-picture data and the encoded main video signal data is separated into encoded main video signal data 322 and encoded sub-picture data 323 by the demultiplexer 321. The separated data 322 and 323 are decoded by the video decoder 324 and the sub-picture decoder 325, respectively, and the decoded main video signal 3 is decoded by the overlay unit 328.
26, the decoded sub-picture 327 is mapped. The video signal mapped by the overlay unit 328 is converted into an analog video signal 22 by the A / D converter 11, and then transmitted to the video signal receiving device 6 via an analog transmission path.

The demultiplexer 3 shown in FIG.
21 to the D / A converter 11 are a conventional DV
This is also included in the D player. The output video signal 22 is resampled and digitized by the A / D converter 12 in the video signal receiving device 6, and
The reference video signal mapped as a sub-picture is extracted by the reference video signal detection unit 330 and used for updating the correction parameter of the video signal correction unit 13. The video signal 24 corrected by the video signal correction unit 13 is descrambled by the digital signal processing unit 14 and output.

In the present embodiment, the main video signal is
When the various scrambling processes described in FIGS. 9 to 35 are performed, if the video of the sub-picture is video data to be originally displayed, the scrambling process synchronized with the scrambling of the related main video frame is also performed on the sub-picture. Shall be applied.

For example, a case where scrambling is performed on a main video signal by exchanging slices shown in FIG. 30 will be described with reference to FIG. FIG. 43 (a)
It shows a video frame that should be displayed originally and consists of a main video frame 340 and a sub-picture 341. 342 extracts only the sub-picture 341.

Here, if the main video frame has been subjected to scramble processing by exchanging slices as shown in FIG.
If scrambling linked to the main video frame is performed as in 5, 346, the signal after the decoded and sub-picture is mapped to the main video signal is subjected to a descrambling process, whereby Both signals of the sub-picture can be descrambled at the same time. For this purpose, the sub-picture 342 shown in FIG.
May be replaced as in 347 in FIG. 43 (b) and encoded. Here, since the portions 348 and 349 in FIG. 43B are regions where the main video signal is displayed, the attribute of the pixel data of the sub-picture is transmitted (Trans).
parent).

On the other hand, as shown in FIG. 41, when transmitting a reference video signal for calculating a correction parameter using a sub-picture, it is necessary to detect the reference video signal before the descrambling process. When scrambling synchronized with the main video signal is applied to the sub-picture as shown in,
It becomes difficult to detect the reference video signal. Therefore, when the sub-picture is a video signal, scrambling synchronized with the main video signal is also performed on the sub-picture as shown in FIG. 43. When the sub-picture is a reference video signal for calculating a correction parameter, Switching and encoding are performed so as not to perform scrambling in synchronization with the main video signal. By doing so, from the video signal before descrambling,
Regardless of the scrambling method of the main video signal, it is possible to detect the reference video signal mapped to the sub-picture.

FIG. 44 shows an example of overlay of a reference video signal mapped to a sub-picture on a main video signal. FIG. 44A shows a case where the main video signal 360 is not scrambled, and the reference video signal 361 is mapped to a sub-picture. FIG.
(B) shows a case where the main video signal 362 is scrambled, and the reference video signal 363 is similarly mapped to the sub-picture. As shown in FIG. 44, since the reference video signal is always mapped to a predetermined position regardless of whether or not the main video signal is scrambled, it is possible to normally detect the reference video signal before the descrambling process. It becomes possible.

[0160]

As described above, after decoding video data on which moving image encoding such as MPEG2 has been performed and transmitting the decoded video signal via an analog transmission path,
In a system that performs re-sampling and performs digital video signal processing such as descrambling of a baseband video signal, it depends on the deviation of the origin position of the effective image area, the deviation of the gain and DC offset of each video signal component, and the transmission characteristics Due to the influence of ringing or echo, the effect of post-filter or video signal format conversion, etc., artifacts may be generated in the reproduced video signal, but according to the present invention, the effective area of the video signal is utilized. Either transmit a reference video signal with a fixed pixel value for each predetermined area unit such as a macroblock or a block, or transmit a reference video signal using a sub-video signal and correct the video signal using this reference signal , It is possible to prevent such artifacts from occurring.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a shift of an effective image area.

FIG. 3 is an exemplary view showing an example of a reference video signal in the embodiment.

FIG. 4 is an exemplary view showing another example of the reference video signal in the embodiment.

FIG. 5 is an exemplary view showing still another example of the reference video signal in the embodiment.

FIG. 6 is a diagram showing an ideal gain characteristic of a transmission line.

FIG. 7 is a view showing an example of gain correction of a transmission line in the embodiment.

FIG. 8 is a view showing another example of the gain correction of the transmission line in the embodiment.

FIG. 9 is a diagram showing another example of the gain correction of the transmission line in the embodiment.

FIG. 10 is a diagram showing still another example of the transmission line gain correction in the embodiment.

FIG. 11 is a diagram showing a configuration example of a waveform equalization filter in the embodiment.

FIG. 12 is a block diagram showing a system configuration according to a second embodiment of the present invention;

FIG. 13 is a block diagram showing a configuration example of a video signal format inverse conversion unit according to the embodiment;

FIG. 14 is a view for explaining an example of the phase relationship between pixel samples in MPEG2 video encoding.

FIG. 15 is a view for explaining another example of the phase relationship between pixel samples in MPEG2 video encoding.

FIG. 16 is a view for explaining another example of the phase relationship between pixel samples in MPEG2 video encoding.

FIG. 17 is a view for explaining still another example of the phase relationship between pixel samples in MPEG2 video encoding.

FIG. 18 is a block diagram showing a configuration example of a video signal format inverse conversion unit according to the embodiment;

FIG. 19 is a block diagram showing another configuration example of the video signal format inverse conversion unit according to the embodiment;

FIG. 20 is an exemplary block diagram showing another configuration example of the video signal format inverse conversion unit according to the embodiment;

FIG. 21 is a diagram illustrating an example of setting an overlap area or an interpolation area for a video signal according to the third embodiment of the present invention.

FIG. 22 is an exemplary view for explaining overlap processing for a video signal in the embodiment.

FIG. 23 is an exemplary view for explaining interpolation processing on a video signal in the embodiment.

FIG. 24 is a view showing an example of setting an overlap area or an interpolation area for a video signal in the embodiment.

FIG. 25 is a view showing an example of mapping of a reference video signal to a video signal in the embodiment.

FIG. 26 is a block diagram showing a configuration example of a video signal additional data detection and mask processing circuit according to the embodiment;

FIG. 27 is an exemplary view showing an example of mask processing of video signal additional data in the embodiment.

FIG. 28 is a block diagram showing a system configuration according to a fourth embodiment of the present invention.

FIG. 29 is a diagram showing an example of a video signal scramble in the embodiment.

FIG. 30 is a view showing another example of the video signal scrambling in the embodiment.

FIG. 31 is an exemplary view showing another example of video signal scrambling in the embodiment.

FIG. 32 is a block diagram showing a configuration example of a video signal descrambling processing unit in the embodiment.

FIG. 33 is a view showing an example of video signal scrambling in the embodiment.

FIG. 34 is a block diagram showing another configuration example of the video signal descrambling unit in the embodiment.

FIG. 35 is a view showing an example of setting a video signal scramble area in the embodiment.

FIG. 36 is a block diagram showing a system configuration according to a fifth embodiment of the present invention.

FIG. 37 is a block diagram illustrating a system configuration example according to an embodiment of the present invention.

FIG. 38 is a flowchart showing an example of a process according to the embodiment;

FIG. 39 is a flowchart showing another example of the process according to the embodiment;

FIG. 40 is a flowchart showing another example of the process according to the embodiment;

FIG. 41 is a diagram showing an example of a reference video signal using a sub video signal according to the sixth embodiment of the present invention.

FIG. 42 is a block diagram showing a system configuration according to the embodiment;

FIG. 43 is a view showing an example of scrambling of a main video signal and a sub video signal in the embodiment.

FIG. 44 is a diagram showing an example of a reference video signal using scrambling of a main video signal and a sub video signal in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Video decoder 11 ... D / A converter 12 ... A / D converter 13, 72 ... Video signal correction part 14 ... Digital signal processing part 15 ... D / A converter 20 ... Video signal coded data 22, 26 ... Analog video signal 27 Digital video signal 70, 73 Video signal format converter 71 Video signal format inverse converter 192 Video reconstructor 195 Additional data detector 220 Descrambler 221 Scramble key information 261 262 263: bit inverter 230: scramble key information detection unit 301: optical disk reproducing device 302: optical disk 303: data memory 305: display device 321: demultiplexer 324: video decoder 325: sub-picture decoder 328: sub-picture overlay unit 330: reference Movie Image signal detector

Continued on the front page F-term (reference) 5C021 PA17 PA36 PA42 PA56 PA58 PA62 PA66 PA67 PA74 PA79 RB00 RB08 SA11 SA22 SA25 XB12 XC00 YC08 ZA00 ZA02 ZA12 5C053 FA24 FA30 GB23 GB38 JA21 JA30 KA09 KA11 KA16 KA30 LA15 5K RC00 RC35 SS06 SS13 UA11 5C064 CB01 CC06

Claims (10)

[Claims] 1. An image comprising a correction means for correcting the position of the processing target video signal using a reference video signal having a fixed pixel value for each predetermined area unit provided together with the processing target video signal. Signal processing device. And a correction means for correcting a gain and a DC offset of the video signal to be processed by using a reference video signal having a fixed pixel value for each predetermined area unit provided together with the video signal to be processed. Characteristic video signal processing device. 3. A waveform equalization filter for equalizing a waveform of a video signal to be processed, and a waveform equalization filter using a reference video signal having a fixed pixel value for each predetermined area unit provided together with the video signal to be processed. And a tap gain determining means for determining a tap gain of the quantization filter. 4. When the signal component of the processing target video signal is converted using a reference video signal having a fixed pixel value for each predetermined area unit provided together with the processing target video signal whose signal component has been converted. A conversion parameter estimating unit for estimating the conversion parameter of: a conversion parameter estimating unit for calculating an inverse conversion parameter for the signal component from the conversion parameter estimated by the conversion parameter estimating unit; A video signal processing apparatus, comprising: an inverse conversion means for performing an inverse conversion of the signal component of the processing target video signal using the inverse conversion parameter. 5. A spatial change amount of a pixel value in an overlap area or an interpolation area for a processing target video signal having an overlap area or an interpolation area of a pixel value for each of a plurality of continuous predetermined area units. A video signal processing device comprising means for selecting or generating a pixel value of an effective image area of the video signal to be processed so that is minimized. 6. Whether or not to provide an overlap area or an interpolation area of the pixel values is set in a predetermined video signal unit, and for a predetermined video signal unit portion in which no overlap area or the interpolation area is provided, an effective image is set. Additional data detecting means for extracting predetermined additional data, wherein predetermined additional data corresponding to the number of pixels to be reduced according to selection or generation of a pixel value of the area is embedded in the effective image area of the video signal to be processed; 6. The video signal processing apparatus according to claim 5, further comprising: a unit that replaces the additional data detected by the additional data detection unit with a predetermined video signal and outputs the video signal. 7. The video according to claim 1, wherein said video signal to be processed is a scrambled video signal, and further comprising a descrambling means for descrambling said video signal. Signal processing device. 8. A reference video signal reproducing means for reproducing a reference video signal from a recording medium on which a reference video signal having a fixed pixel value for each predetermined area unit is recorded, and a reference video signal reproduced by the reference video signal reproducing means. Using the reference video signal, (a) the position correction amount of the video signal, (b) the correction amount of the gain and DC offset of the video signal, (c) the tap gain of the waveform equalization filter for the video signal, (d) Parameter determining means for determining at least one of the inverse conversion parameters for the converted signal component of the video signal; parameter storing means for storing the parameter determined by the parameter determining means; and recording for recording the reference video signal A processing target video signal reproducing means for reproducing the processing target video signal recorded on the same or different recording medium as the medium, and the processing target video signal reproducing means A correction means for correcting the reproduced video signal to be processed in accordance with the parameters stored in the parameter storage means. 9. An encoded data of a main video signal, (a) a position correction amount of the video signal, (b) a correction amount of a gain and a DC offset of the video signal, and (c) a waveform equalizing filter for the video signal. Tap gain of (d) including a reference video signal for determining at least one parameter of the inverse conversion parameter for the converted signal component of the video signal, the encoded data of the sub-video signal accompanying the main video signal, Coded data receiving means for receiving via a transmission or recording medium; main video signal decoding means for decoding coded data of the main video signal received by the coded data receiving means; Means for decoding the encoded data of the sub-video signal received by the means; and means for decoding the sub-video signal on the main video signal obtained by the main video signal decoding means. Mapping means for mapping the sub-video signal obtained by the above, video signal receiving means for receiving a video signal in which a main video signal is mapped to a sub-video signal by the mapping means, and video received by the video signal receiving means Sub-video signal extracting means for extracting the mapped sub-video signal from the signal; parameter determining means for determining at least one of the parameters (a) to (d) using the reference video signal; and A video signal processing device for correcting the video signal received by the video signal receiving device according to the parameters determined by the video signal receiving device. 10. A coded data receiving means for transmitting coded data of a main video signal and coded data of a sub video signal accompanying the main video signal via a transmission or recording medium, and said coded data receiving means. Main video signal decoding means for decoding the coded data of the main video signal received by the sub-picture signal, and sub-video signal decoding means for decoding the coded data of the sub-video signal received by the coded data receiving means Mapping means for mapping the sub video signal obtained by the sub video signal decoding means onto the main video signal obtained by the main video signal decoding means; and a sub video signal to the main video signal by the mapping means. A video signal receiving means for receiving a video signal to which the video signal is mapped; A scrambling process is performed on the main video signal or encoded data of the main video signal, and the main video signal or the main video is encoded on the sub video signal or the encoded data of the sub video signal. A video signal processing device, wherein a scrambling process equivalent to the scrambling process is performed in synchronization with the scrambling process on the encoded data of the signal.