JPH0837672A - Color component video signal system converter - Google Patents

Abstract

PURPOSE:To prevent the degradation of picture quality even when a video signal system is repeatedly converted between the video signals of a 4:2:2 format and the video signals of a 4:2:0 format. CONSTITUTION:The video signals of the 4:2:2 format are converted into the video signals of the 4:2:0 format in this color component video signal system converter 2 and then, inputted to a video equipment 3. Also, the video signals of the 4:2:0 format outputted from the video equipment 3 are converted into the video signals of the 4:2:2 format in the color component video signal system converter 2 and outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color component video for performing a signal format conversion process between a video signal of a 4: 2: 2 format and a video signal of a 4: 2: 0 format which are color component video signals. The present invention relates to a signal format converter.

[0002]

2. Description of the Related Art Conventionally, as one of video signals used in a digital video tape recorder (DVTR),
There is a color component video signal. This color component video signal is often used in the so-called 4: 2: 2 format, which is composed of a luminance signal Y and two color difference signals RY and BY, but is handled in the 4: 2: 0 format. In some cases This 4: 2: 0
A color component video signal of a format is handled by a device that performs image compression processing according to, for example, the so-called MPEG (moving image coding for storage) system.

A video signal of 4: 2: 2 format and a video signal of 4: 2: 0 format will be described.

The video signal of the 4: 2: 2 format is
The luminance signal Y is sampled at a sampling frequency of 13.5 MHz, and the color difference signals RY and BY are sampled at a sampling frequency of 6.76 MHz, respectively. It is a signal in which -Y and BY are multiplexed. Also, a video signal of 4: 2: 0 format is 4: 2:
With respect to the luminance signal Y similar to the luminance signal Y of the two-format video signal, the color difference signals R-Y, B-
It is a signal in which Y is multiplexed. Therefore, the 4: 2: 0 format video signal can be generated by converting the 4: 2: 2 format video signal.

When converting a 4: 2: 2 format video signal to a 4: 2: 0 format video signal, a sub-sampling process is performed on the 4: 2: 2 format video signal. When performing this sub-sampling process, to avoid aliasing noise,
The 4: 2: 2 format video signal is blocked in advance by a low pass filter (LPF) to block high frequency components.

When converting a 4: 2: 0 format video signal to a 4: 2: 2 format video signal, interpolation processing is performed on the 4: 2: 0 format video signal.

[0007]

[Problems to be Solved by the Invention] By the way, 4: 2: 2
When the conversion of the format video signal to the 4: 2: 0 format video signal and the conversion of the 4: 2: 0 format video signal to the 4: 2: 2 format video signal are repeated, 4: When converting a 2: 2 format video signal to a 4: 2: 0 format video signal, the LPF is passed each time. Therefore, every time the LPF is passed through the video signal, the high-frequency component of the video signal gradually decreases due to the characteristics of the LPF, and the image quality of the video signal gradually deteriorates.

In view of the above-mentioned circumstances, the present invention provides a method for converting a color component video signal between a 4: 2: 2 format video signal and a 4: 2: 0 format video signal, Provided is a color component video signal system conversion device which does not deteriorate the image quality of a processed video signal.

[0009]

A color component video signal system converter according to the present invention converts a video signal in a 4: 2: 2 format into a video signal in a 4: 2: 0 format or in a 4: 2: 0 format. A color component video signal system conversion device for converting a video signal according to the above into a video signal according to the 4: 2: 2 format, wherein when converting a video signal according to the 4: 2: 2 format into a video signal according to the 4: 2: 0 format In the above, a part of the lines of the color difference signal in the video signal of the 4: 2: 2 format is deleted, and the thinning processing means for outputting the remaining lines as they are to generate a video signal of the 4: 2: 0 format. Converts video signals in 4: 2: 0 format to video signals in 4: 2: 2 format In this case, the line of the color difference signal in the video signal of the 4: 2: 0 format is used as it is, and the interpolation processing means for interpolating the remaining line generates the video signal of the 4: 2: 2 format. Solve the problem.

Further, after converting the video signal in the 4: 2: 0 format into a video signal in the 4: 2: 2 format, the video signal in the 4: 2: 2 format is further converted in the 4: 2: 0 format. When converting to a video signal, among the color difference signals of the video signal in the 4: 2: 2 format, the first 4: 2:
It is characterized in that the lines of the color difference signals in the 0 format video signal are output as they are and the remaining lines are deleted.

Here, the thinning-out processing means is characterized in that the color difference signals for each field are thinned out every other line.

Further, the thinning-out processing means is characterized in that only one of the fields consisting of an odd field and an even field is taken out.

Further, the interpolation processing means is characterized by performing an average value interpolation processing.

[0014]

According to the present invention, a 4: 2: 2 format video signal is converted into a 4: 2: 0 format video signal, and the converted 4: 2: 0 format video signal is converted to 4: 2. : Repeat the operation of converting to a 2-format video signal.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration when a color component video signal system conversion apparatus according to the present invention is used. The color component video signal system conversion device 2 of FIG. 1 performs a video signal system conversion between a video signal of 4: 2: 2 format and a video signal of 4: 2: 0 format.

In the 4: 2: 2 format video signal, the luminance signal Y has a sampling frequency of 13.5 MHz,
The color-difference signals RY and BY are sampled at a sampling frequency of 6.76 MHz, respectively, and the luminance signal Y is multiplexed with the color-difference signals RY and BY for each line. is there. In addition, the video signal of 4: 2: 0 format is
With respect to the luminance signal Y similar to the luminance signal Y of the 4: 2: 2 format video signal, the color difference signal R- every other line.
It is a signal in which Y and BY are multiplexed.

A 4: 2: 2 format video signal output from a signal output terminal 1 of a device or the like that handles a 4: 2: 2 format video signal is input to a color component video signal system converter 2. The color component video signal system converter 2 converts an input video signal of 4: 2: 2 format into a video signal of 4: 2: 0 format. The converted video signal in the 4: 2: 0 format is output to the video device 3. This video device 3 is specifically an MPEG.
A VTR or the like that performs image compression processing according to the method, such as 4:
It is provided with an input terminal and an output terminal for a 2: 0 format video signal, and performs image compression processing and the like using the 4: 2: 0 format video signal.

The 4: 2: 0 format video signal output from the video device 3 is input to the color component video signal system conversion device 2. In this color component video signal system converter 2,
The input 4: 2: 0 format video signal is 4:
It is converted to a video signal in the 2: 2 format. The converted video signal in the 4: 2: 2 format is 4: 2.
It is sent to the signal input terminal 4 of a device that handles a 2: 2 format video signal.

Here, when the video equipment 3 is a VTR, the image quality is deteriorated when an operation such as repeating dubbing of an input video signal in the VTR is performed. However, the video signal output from the video device 3 becomes the same video signal as the input video signal, and the image quality of the color component video signal system conversion device 2 does not deteriorate.

Next, the conversion processing of the video signal system in the color component video signal system conversion device 2 will be described below.

Specifically, when a 4: 2: 2 format video signal is input to the color component video signal system conversion device 2, the 4: 2: 2 format video signal is subjected to decimation processing. To a 4: 2: 0 format video signal. Also, 4: 2: 0
When a format video signal is input, this 4: 2: 0 format video signal is subjected to interpolation processing to be converted into a 4: 2: 2 format video signal.

Next, the thinning process of the color component video signal system conversion apparatus will be described with reference to FIG.

The video signal of the 4: 2: 2 format is
A luminance signal Y and two color difference signals RY having the same number of lines;
It is composed of BY. For example, in the case of the NTSC 525/60 system used for color television broadcasting, since there are 525 scanning lines per frame, as shown in FIG. 2A, the luminance signal Y and the color difference signal R-
Each of Y and BY is 525. Here, for example, when there are 480 scanning lines in the effective screen area, when thinning processing is performed on the video signal of 4: 2: 2 format to convert into a video signal of 4: 2: 0 format, The number of lines in the effective screen area of the luminance signal Y is set to 480 as shown in FIG.
The number of lines in the effective screen areas of Y and BY is 240 respectively.
Processing is done so that it becomes a book. That is, the number of lines of the color difference signals RY and BY in the video signal of 4: 2: 0 format is the number of lines of the color difference signals RY and BY in the video signal of 4: 2: 2 format. The number of lines is half each. At this time, the luminance signal Y and the color difference signals RY and BY of the 4: 2: 0 format video signal output by this thinning-out process are the luminance signals of the input 4: 2: 2 format video signal. Y and color difference signal R-
Delete part of the line without processing Y and BY
The rest of the line is output as is.

The method for determining whether to leave or delete each line of the color difference signals RY and BY of the video signal of 4: 2: 2 format has a certain law. Any algorithm may be used.

The interpolation processing of the color component video signal system conversion apparatus will be described with reference to FIG.

When a video signal of 4: 2: 0 format is converted to a video signal of 4: 2: 2 format, as shown in FIG. 3, the color difference signal R in the video signal of 4: 2: 0 format is used. -Y and BY line data are color difference signals R- of a 4: 2: 2 format video signal.
It is placed at the original line position in Y, BY. Further, the line data of the color difference signal in the video signal of the 4: 2: 0 format is used to interpolate the line data between these lines. By performing such an interpolation process, a video signal of 4: 2: 0 format is converted into 4: 4.
Converts to a 2: 2 format video signal.

Next, FIG. 4 shows an embodiment in which a plurality of thinning-out processing circuits and interpolation processing circuits are connected in series as a case of repeatedly performing the above-described thinning-out processing and interpolation processing.

The 4: 2: 2 format video signal input from the signal terminal 10 is sent to the thinning processing circuit 11. In the thinning processing circuit 11, the sent 4: 2:
The 2 format video signal is converted into a 4: 2: 0 format video signal by subjecting it to the thinning processing described above.
The converted video signal in the 4: 2: 0 format is sent to the interpolation processing circuit 12. In the interpolation processing circuit 12, the sent video signal of 4: 2: 0 format is subjected to the above-mentioned interpolation processing to be converted into a video signal of 4: 2: 2 format. The converted video signal of 4: 2: 2 format is sent to the thinning processing circuit 13. Similar to the thinning processing circuit 11, the thinning processing circuit 13 performs the above-described thinning processing on the sent 4: 2: 2 format video signal to convert it into a 4: 2: 0 format video signal. The converted video signal in the 4: 2: 0 format is sent to the interpolation processing circuit 14. In the interpolation processing circuit 14, the interpolation processing circuit 12
Similarly, the above-mentioned interpolation processing is applied to the sent 4: 2: 0 format video signal to convert it to a 4: 2: 2 format video signal. The converted video signal in the 4: 2: 2 format is output from the signal terminal 15.

FIG. 5 shows the state of the video signal when the thinning process and the interpolation process as shown in FIG. 4 are repeated.
Shown in

FIG. 5A shows the state of the color difference signal of the original 4: 2: 2 format video signal before conversion processing which is input from the signal terminal 10. This 4: 2: 2
The color difference signal of the video signal of the format is thinned by the thinning processing circuit 11 and is converted into the color difference signal of the video signal of the 4: 2: 0 format as shown in FIG. 5B by the remaining lines. It This 4: 2:
Each line of the color difference signal of the 0 format video signal is
In the interpolation processing circuit 12, as shown by the solid line in FIG. 5C, the same phase as that in the color difference signal of the original 4: 2: 2 format video signal is output. The line deleted from the color difference signal of the original 4: 2: 2 format video signal is restored by the interpolation process using the remaining line as shown by the dotted line in FIG. 5C.

Thereafter, the thinning-out processing circuit 13 performs the same thinning-out processing on the color difference signal of the video signal in the 4: 2: 2 format shown in FIG. At this time, 4: 2: shown in b of FIG.
A data string on the same line as the line of the color difference signal of the 0 format video signal is left as shown in d of FIG.

Further, the interpolation processing circuit 14 performs the same interpolation processing as that of the interpolation processing circuit 12 on the color difference signal of the video signal in the 4: 2: 0 format shown in FIG. 5D. At this time, as shown in e of FIG. 5, c of FIG.
Is converted into a data string of the same line as the line of the color difference signal of the 4: 2: 2 format video signal shown in FIG.

As described above, the data strings of the color difference signal lines of a and d of FIG. 5 obtained by the thinning processing are the same as the color difference signal of the original 4: 2: 2 format video signal shown in FIG. 5a. The data string of some lines will be obtained as it is without being changed, and the interpolated data string in the data string of the color difference signal lines of c and e of FIG. Since the interpolation is performed using the line that does not always change, the same data string is always obtained.

Further, FIG. 6 shows a configuration in the case where an image processing apparatus which handles a video signal of a 4: 2: 0 format is connected when the thinning processing and the interpolation processing are repeatedly performed as shown in FIG. .

At this time, the 4: 2: 2 format video signal input from the signal terminal 20 is sent to the thinning processing circuit 21 to be thinned and converted into a 4: 2: 0 format video signal. After that, it is sent to the 4: 2: 0 image processing circuit 22. This 4: 2: 0 image processing device 2
In 2, image processing is performed using the sent 4: 2: 0 format video signal. The 4: 2: 0 image processing device 22 outputs the sent video signal of the 4: 2: 0 format as it is to the interpolation processing circuit 23. In the interpolation processing circuit 23, the video signal of the 4: 2: 0 format is subjected to interpolation processing and then 4: 2: 2.
The converted video signal is sent to the thinning processing circuit 24. In this thinning-out processing circuit 24, 4:
The 2: 2 format video signal is thinned out, and the 4: 2: 0 format video signal is converted to 4: 2: 0.
It is output to the image processing device 25. The 4: 2: 0 image processing device 25 also performs the same image processing as that of the 4: 2: 0 image processing device 22 and also receives the input 4: 2: 0.
The video signal of the format is used as it is for the interpolation processing circuit 26.
Is output to In this interpolation processing circuit 26, 4: 2: 0
4: 2:
It is converted to a video signal in two formats. This 4: 2:
The 2-format video signal is output from the signal terminal 27.

Here, the data output from the thinning processing circuit 21 and the data output from the thinning processing circuit 24 are the same data, and coincide with a part of the original data. Therefore, the 4: 2: 0 image processing apparatus 2 and the 4: 2: 0 image processing apparatus 25 are connected in a system in which a 4: 2: 2 format video signal is input / output.
It can be regarded as being directly connected to the system in which a 4: 2: 0 format video signal is input / output. This eliminates the deterioration of the image quality when the video signal is input / output.

Next, the thinning processing circuit and the interpolation processing circuit will be specifically described below.

First, FIG. 7 shows a specific configuration of the thinning-out processing circuit, and FIG. 8 shows the timing of each control signal in the thinning-out processing circuit shown in FIG.

In the 4: 2: 2 format video signal input from the signal input terminal 30 of FIG. 7, only the data of the necessary line is selected in the memory 31 by the write enable signal input from the signal input terminal 32. By being written, the video signal in the 4: 2: 0 format is stored in the memory 31. The video signal stored in the memory 31 is read based on the read permission signal input from the signal input terminal 32, and the signal output terminal 33 is read.
Output from

Specifically, the write enable signal input to the signal input terminal 32 of FIG. 7 is obtained by thinning out the lines in one frame for each line as shown in FIG. Is the write enable signal WE ₁ for writing the data of (1) to the memory 31. In addition, as shown in b of FIG. 8, the data of one of the odd field and the even field forming one frame is set to 1
It may be a write enable signal WE ₂ that causes the memory 31 to write data in every field. According to the write permission signal WE ₁ or the write permission signal WE ₂ , the memory 3
The data written in 1 is the write enable signal WE ₁
Alternatively, it is read from the memory 31 by the read permission signal RE _{1 of} FIG. 8c or the read permission signal RE ₂ of d of FIG. 8 corresponding to the write permission signal WE ₂ , respectively.

Further, FIG. 9 shows a specific configuration of the interpolation processing circuit.

The video signal of 4: 2: 0 format input from the signal input terminal 40 of FIG. 9 is written and stored in the memory 41. The 4: 2: 0 format video signal stored in the memory 41 is sent to the selector 44 and the line memory 42. This line memory 42
Then, the sent video signal is stored as data for each line and sent to the interpolation processing unit 43. In the interpolation processing unit 43, when the video signal of 4: 2: 2 format is converted into the video signal of 4: 2: 0 format by the average value interpolation processing or the like using the sent data for each line, it is deleted. The data of the selected line. The generated line data is sent to the selector 44. In the selector 44, the video signal of the 4: 2: 0 format sent from the memory 41 and the data of the line for interpolation sent from the interpolation processor 43 are selected to be switched, so that the signal output terminal 45. Outputs a video signal of 4: 2: 2 format.

[0043]

As is apparent from the above description, the color component video signal system converter according to the present invention converts a video signal in a 4: 2: 2 format to a 4: 4 format.
Video signal in 2: 0 format or 4: 2:
A color component video signal system converter for converting a video signal in the 0 format into a video signal in the 4: 2: 2 format, which converts a video signal in the 4: 2: 2 format into a video signal in the 4: 2: 0 format. In this case, a part of the color difference signal lines in the 4: 2: 2 format video signal is deleted and the remaining lines are output as they are, so that a 4: 2: 0 format video signal is generated. The video signal in the 4: 2: 0 format is 4: 4.
When converting to a video signal in the 2: 2 format, the line of the color difference signal in the video signal in the 4: 2: 0 format is used as it is, and the interpolation processing means for interpolating the remaining line uses the 4: 2: 2 format. By generating the above video signal, the image quality does not deteriorate even if the video signal system conversion is repeatedly performed between the 4: 2: 2 format video signal and the 4: 2: 0 format video signal. .

After the video signal in the 4: 2: 0 format is converted into the video signal in the 4: 2: 2 format, the video signal in the 4: 2: 2 format is further converted in the 4: 2: 0 format. When converting to a video signal, among the color difference signals of the video signal in the 4: 2: 2 format, the first 4: 2:
In the conversion from the 4: 2: 0 format to the 4: 2: 2 format, the lines of the color difference signal in the video signal in the 0 format are output as they are and the remaining lines are deleted, so that the lines are interpolated in the color difference signal. Since only a fixed number of lines are deleted and the remaining lines are always output in the same phase, the image quality is not deteriorated even if the video signal converted by this video signal conversion is used.

Here, in the thinning processing means, the color difference signals for each field are thinned out every other line, or only one of the fields of the odd field and the even field is taken out. The thinning process of the video signal can be performed.

Further, the interpolation processing means can easily perform the interpolation processing of the video signal by performing the average value interpolation processing.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration when a color component video signal system conversion apparatus according to the present invention is used.

FIG. 2 is a diagram showing a conversion state of a video signal by thinning processing.

FIG. 3 is a diagram showing a conversion state of a video signal by interpolation processing.

FIG. 4 is a diagram showing a configuration in a case where a thinning process and an interpolation process are repeatedly performed.

FIG. 5 is a diagram showing a state of a video signal when the thinning-out process and the band interpolation process are repeatedly performed.

FIG. 6 is a diagram showing a configuration in the case where a 4: 2: 0 image processing apparatus is connected when the thinning processing and the interpolation processing are repeatedly performed.

FIG. 7 is a diagram showing a specific configuration of a thinning processing circuit.

FIG. 8 is a diagram showing timings of a write permission signal and a read permission signal of a thinning processing circuit.

FIG. 9 is a diagram showing a specific configuration of an interpolation processing circuit.

[Explanation of symbols]

 2 Color component video signal system conversion device 3 Video equipment 11, 13 Thinning processing circuit 12, 14 Interpolation processing circuit

Claims (5)

[Claims] 1. A video signal of 4: 2: 2 format is converted to a video signal of 4: 2: 0 format, or a video signal of 4: 2: 0 format is 4: 2: 2.
A color component video signal format conversion device for converting a video signal according to a format, wherein the video signal according to the 4: 2: 2 format is 4: 2: 0.
When converting to a video signal in the format, a part of the lines of the color difference signal in the video signal in the 4: 2: 2 format is deleted and the remaining line is output as it is by the thinning processing means 4: 2: 0. Generate a video signal of the format, and convert a video signal in the 4: 2: 0 format to 4: 2: 2
When converting to a video signal in the format, the line of the color difference signal in the video signal in the 4: 2: 0 format is used as it is, and the interpolation processing means for interpolating the remaining line uses the video signal in the 4: 2: 2 format. A color component video signal format conversion device, which is characterized in that: 2. The video signal according to the 4: 2: 0 format is converted into the video signal according to the 4: 2: 2 format, and the video signal according to the 4: 2: 2 format is further converted according to the 4: 2: 0 format. When converting to a video signal, among the color difference signals of the video signal in the 4: 2: 2 format, the line of the color difference signal in the video signal in the first 4: 2: 0 format is output as it is, and the remaining lines are output. 2. The color component video signal format conversion apparatus according to claim 1, wherein lines are deleted. 3. The color component video signal system conversion apparatus according to claim 1, wherein said thinning-out processing means thins out the color difference signals for each field every other line. 4. The color component video signal system conversion apparatus according to claim 1, wherein the thinning-out processing means extracts only one of the fields consisting of an odd field and an even field. 5. The color component video signal system conversion apparatus according to claim 1, wherein said interpolation processing means performs an average value interpolation processing.