JPH06268911A - Video signal processor - Google Patents

Abstract

PURPOSE:To reduce jitter of a character by extending a period discriminated to be a character for a predetermined period before and after a character signal of moving object in excess of a predetermined luminance level. CONSTITUTION:The processor is provided with an A/D converter 12, a title section data gate circuit 14, a field memory 15, delay circuits 16, 17 delaying data by a predetermined time, a quantity comparator 18, a switching signal processing circuit 20, and a 2-way selector 21. When a video software of a cinema size whose upper and lower video image is missing is reproduced while being extended fully on a screen, superimposed characters in excess of the screen is moved and synthesized to a video image in the screen. In this case, when a character is extracted from the character area, an extended character period adding a period for a predetermined width is generated before and after the period where the luminance level of the video signal exceeds the character discrimination level, the video signal of the character is selected for the extended character period and the video signal being the character moving destination is selected for the other period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video reproducing apparatus having a display screen having a wide aspect ratio (for example, an aspect ratio of 16: 9) which is wider than the aspect ratio of a conventional television screen, and more particularly, is reproduced. The present invention relates to a video playback device that can change the position of subtitles of video software.

[0002]

2. Description of the Related Art In high-definition broadcasting, which is expected as a next-generation television broadcasting, an experimental broadcasting from a broadcasting satellite (BS) is upgraded to a test broadcasting, and the broadcasting time is extended to 8 hours a day. This HD (High Definition TV:
HDTV is the abbreviation for Japanese system), which has about twice the horizontal and vertical resolution of the current TV, and has a wide aspect ratio of 16: 9, which is the aspect ratio of the screen (horizontal to vertical). Wave (VHF, UHF) The aspect ratio of TV broadcasting is 4: 3, which is horizontally long.

Wide-aspect television receivers currently on the market have a genuine high-definition television that reproduces this high-definition broadcast at the original resolution and the same number of scanning lines as the high-definition television, 1125, but a simplified MUSE decoder. Type HDTV and a horizontal screen television with 525 scanning lines, which is equipped with a MUSE-NTSC converter and has the same number of scanning lines.

Conventionally, in television broadcasting using a movie as a source or in video software of a movie, in order to display the entire original screen without trimming, the width of the screen having an aspect ratio of 4: 3 is used to display the image. Some have the same width. When such a television broadcast or video software is displayed on a display screen having a normal aspect ratio of 4: 3, a blank portion called a blank area called a blank area is displayed as a black band above and below the display screen.

When reproducing an image called such a cinema size on a television having a wide aspect ratio, the image portion on the display screen is expanded at the same aspect ratio,
By matching the vertical length of the video portion with the vertical length of the display screen, the video is played back to the full extent of the display screen, and a powerful video can be enjoyed. In some cinema-size video software that lacks video at the top and bottom, the subtitle super is placed in the blank area.In this case, when the video is expanded to fill the display screen, the subtitles will stick out of the display screen. Disappears.

Therefore, by delaying the video signal of the subtitle portion and synthesizing it with the video of the next image frame, the position of the subtitle superimposition is moved to the inside of the display screen, and the video is enlarged and displayed on the display screen. A function is provided to make the subtitles visible. As a conventional technique of such a subtitle moving means, there is a "video signal processing device" (Japanese Patent Laid-Open Publication No. 3-1.
No. 27565) is known.

A block diagram of this conventional example is shown in FIG. In the figure, 401 is a video input extracted as a luminance signal by a Y / C separation circuit, and 402 is an analog / digital converter (hereinafter A) for converting an analog video signal into a digital signal.
/ D converter), 403 is a sampling gate signal indicating a caption area, 404 is an AND gate for extracting only the caption area from the digitized video signal, and 405 is movement of the extracted caption area to the next frame. A field memory for delaying until the end, 406 is a comparison value input for determining a character portion in a subtitle, 407 is a comparator for comparing the comparison value with the read value of the field memory 405, 40
Reference numeral 8 is a selector for switching the video signal A / D converted by the output of the comparator 407 and the output of the field memory 405.

The operation of this prior art will be described below. Y
The luminance signal after the / C separation is processed by the A / D converter 402.
It is converted into parallel digital data of 8 bits and 256 gradations at a predetermined sampling period. The field memory 405 is a FIFO type memory capable of storing the output of the sampling gate in a maximum of one field, and its read timing takes a delay time into consideration so that the subtitles come to a desired position of the video data.

The comparator 407 has a field memory 405.
To generate a signal for switching the output from the A / D converter 402 and the output from the comparison data input terminal 406.
The comparison value for character determination given by the above is compared with the read value of the field memory 405. If the read value of the field memory 405 is larger than the comparison value as a result of this comparison, the output of the selector 408 is switched to the data from the field memory 405 in order to display the character. If the comparison result is the opposite, the output of the selector 408 is switched to the data from the analog / digital converter / D converter 402 in order to display the image. In this way, at the output of the selector 408, a signal in which the caption and the video are combined is obtained.

[0010]

However, in such a conventional caption movement of the digital signal processing system, the phase difference between the analog video signal and the sampling clock is
It may differ between frames. For example, in FIG. 5, if the video signal of the first frame is A and the video signal of the second frame is A'when the sampling clock is used as a reference, the sample values between frames are as shown in FIG. Differently, the video signals of the first and second frames are quantized as shown in FIGS. 5B and 5C, respectively.

The video signals quantized and digitized in this way are converted into the video signals of the moving destination shown in FIG. 5D and the subtitles of the moving target by using the comparison values for character level determination. When combined, the first frame becomes the same figure (e) and the second frame becomes the same figure (f). Since (e) and (f) in the same figure are displayed alternately on the display screen, (g) in the same figure.
The luminance within the range indicated by the shaded area will be seen as the character jitter.

However, in the case where the video to which the subtitles have been moved is a relatively dark scene, there is a problem in that the characters having high brightness on the image display screen have jitter, which is very annoying to the video viewer. In view of the above problems, an object of the present invention is to provide a video signal processing device that reduces the jitter of characters after movement even when the phase difference between the analog video signal and the sampling clock differs between frames. is there.

[0013]

In order to solve the above problems, the present invention has the following constitution. That is, the present invention is
Moves the subtitle position when playing a video with a wide aspect ratio that is wider than the aspect ratio of a conventional television screen and a video that has a subtitle in the blank area of the display screen when played with the conventional aspect ratio In a video reproducing apparatus including a caption moving unit that performs, a comparing unit that detects a caption period in which the brightness level of the video signal is higher than a predetermined level, and the detected caption period, with respect to the video signal, A subtitle period extending means for outputting the extended subtitle period by extending forward and backward by a predetermined period, and a synthesizing means for synthesizing the video signal of the subtitle moving destination and the video signal of the subtitle portion based on the extended subtitle period. Is a video signal processing device.

[0014]

According to the present invention, with the above-described configuration, when a cinema size video software having a vertically lacking video is expanded to the full screen and played back, the subtitle super that extends outside the screen is moved to move the video part within the screen. And synthesize. At this time, when extracting characters from the subtitle area, an extended subtitle period is created by adding a period of a predetermined width before and after the period when the luminance level of the video signal exceeds the character determination level. Video signal synthesis is performed by selecting a video signal of a part and selecting a video signal of a subtitle moving destination during other periods. With this, even a region having relatively low brightness around each character forming the subtitle can be moved together with the character, so that the jitter generated on the left and right of the character can be reduced.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram of one embodiment according to the video signal processing device of the present invention. In the figure, 101 is an analog video input signal, and 12 is 8-bit analog /
A digital converter (hereinafter, abbreviated as A / D converter) 102 is a caption part determination signal from a caption part determination circuit (not shown), 14 is a caption part data gate circuit,
15 is an 8-bit field memory, and 16 and 17
Is a delay circuit that delays 8-bit data for a predetermined time, 18 is an 8-bit magnitude comparator (magnitude comparator), 103 is an 8-bit character determination input terminal, and 20 is a switching signal processing circuit. And 2
Reference numeral 1 is an 8-bit 2-way selector, and 104 is a composite output signal.

Next, the operation of the embodiment shown in FIG. 1 will be described in detail. In the following description, positive logic is used, and the high level of the logic signal is abbreviated as H and the low level is abbreviated as L. The analog video input signal is quantized and coded in amplitude by an 8-bit A / D converter 12 having a resolution of 256 gradations at each clock cycle, which is a predetermined sampling cycle. It is converted into a digital video signal 151.

The digital video signal 151 is connected to the subtitle data gate circuit 14 and the delay circuit 16.
The subtitle data gate circuit 14 uses the subtitle portion determination signal that becomes H when it is determined that the blanking area includes subtitles.
The video signal 151 is gated. As a result, the field memory write data 152 becomes an 8-bit video signal in the subtitle portion and becomes 0 in the non-subtitle portion.

The write data 152 is sequentially written in the field memory 15, and is read out after the writing by a time corresponding to a screen scanning period from the original subtitle position to the subtitle moving position of the next field. In this way, the field memory 15 matches the timing of the moving image with the moving target subtitles. The field memory output 153 is connected to the delay circuit 17 and the comparator 18.

In the comparator 18, the field memory output 1
53 (A) is compared with 8-bit comparison data (B) given from the comparison data input terminal 19, and when the field memory output 153 is larger than or equal to the comparison data (A ≧ B), the comparator output Set 154 to H. When A <B, the comparator output 154 is set to L. The comparison data 19 serves as a reference for determining whether each pixel of the field memory output 153 is equal to or higher than a predetermined brightness level or lower than a predetermined brightness level. The period in which the level of the field memory output 153 is at the level of this comparison data 19 or higher is the subtitle period, and this subtitle period and the comparator output 154 are H level.
Matches the period.

The switching signal processing circuit 20 is a circuit for creating the switching signal 155 for the synthesizing circuit 21, and is backward from the comparator output 154 in the period in which the comparator output 154 is H (to the later side). A switching signal 155 extended by 4 clocks is created. The switching signal 155 serves as a switching signal between the moving image and caption in the synthesizing circuit 21. However, since the extension of the subtitle period is extended by 4 clocks backward as described above, it is necessary to distribute the extension period of 4 clocks by 2 clocks before and after. Therefore, the destination video, that is, the A / D converter output 151 and the subtitle, that is, the read output 153 of the field memory 15 are delayed by two clocks using the delay circuits 16 and 17, respectively.

As a result, it is possible to obtain an extended subtitle period of 4 clocks, which is two clocks before and after the subtitle period. The delay circuits 16 and 17 each include two stages of 8-bit registers, and sequentially transfer parallel 8-bit inputs to the registers to obtain delayed data after two clocks. Synthesis circuit 21
Represents the delayed video signal 156 and the delayed subtitle data 157,
By switching in accordance with the switching signal 155, the video and the caption are combined, and the combined output 158 is output to the D / A converter (not shown).

Next, the details of the delay circuits 16 and 17 and the switching signal processing circuit 20 are shown in FIG.
Shown together with the block. FIG. 3 is a time chart showing the operation of the circuit of FIG. In FIG. 2, the delay circuit 16 includes 8-bit registers 201 and 20 respectively.
Similarly, the delay circuit 17 is composed of 8-bit registers 203 and 204, respectively. The switching signal processing circuit 20 includes D-type flip-flops (hereinafter abbreviated as DFF) 205, 206, 207 and 208 connected in series and a 5-input OR circuit 209.

The comparator 18 is an 8-bit magnitude comparator (magnitude comparator), and the combining circuit 21 is an 8-bit 2-way selector (or 8-bit 2-input multiplexer). Since the function and the configuration method of the size comparator and the two-way selector are well known, the description thereof will be omitted. 8-bit registers 201, 20
2, 203 and 204, and DF. F205, 206, 2
Although a single clock is distributed to each of 07 and 208, they are omitted in FIG.

The output 154 of the comparator 18 is the D.F.F.
It is connected to the input Da of 205, and the output Qa of 205 is D-
FF Connected to the input Db of 206 and output Q of 206
b is D-F.F. 207 is connected to the input Dc,
Output Qc of D-F.F. It is connected to the input Dd of 208. The inputs of the 5-input OR circuit 209 are connected to the output 154 of the comparator 18 and the D.F.F. Outputs Qa, Qb, Qc, and Qd are connected. D-
FF The signal input to the 205 is the D.F.F. To each DF.
As shown in FIG. 3, a signal delayed by one clock from the preceding stage is obtained at the output of each.

The 5-input OR circuit 209 has an output 154 of the comparator 18 and a Q which is sequentially delayed by one clock.
Since a to Qd are input, the output 1 obtained by extending the period H by 4T as compared with 154 as shown in FIG.
55 is obtained, which serves as a switching signal for the synthesizing circuit 21.
On the other hand, the two data inputs of the synthesis circuit are the delay circuit 1
The data is delayed by 2T by 6 and 17 and then input to the data input of the combining circuit 18. In this way, the period determined by the comparator 18 to be the subtitle period is divided into two periods.
It is possible to select the caption signal from the field memory during the caption selection period in which each T is expanded and to select the destination video signal during the other period.

Although the preferred embodiment has been described above, this is not meant to limit the invention. For example, in the embodiment, D
Although the data and control signals are delayed by using the type FF, it is also possible to realize by using other delay means.

[0027]

As described above, according to the present invention,
When expanding cinema-size video software to the full screen and playing it back, the subtitles that extend outside the screen are moved and combined with the video part within the screen. At this time, the period determined to be a character beyond the predetermined brightness level is extended by a predetermined period before and after the character signal to be moved. This allows
Even if the phase difference between the analog video signal and the sampling clock may differ between frames, the low brightness part before and after the moved character (left and right of the character on the display screen) also moves with the character. There is an effect that the brightness of the edge of the is gently reduced, and the jitter of characters is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a video signal processing device according to the present invention.

FIG. 2 is a detailed circuit diagram of an essential part of an embodiment of the present invention.

FIG. 3 is a time chart of essential parts of an embodiment of the present invention.

FIG. 4 is a block diagram of a conventional example.

FIG. 5 is an explanatory diagram of jitter of moving characters.

[Explanation of symbols]

 12 analog / digital converter (A / D converter) 14 caption data output gate 15 field memory 16, 17 delay circuit 18 comparator 20 switching signal processing circuit 21 combining circuit 101 video input signal 102 caption part determination signal 103 comparison data 104 combining Output signal

Claims (1)

[Claims] 1. A wide-aspect display screen horizontally longer than the aspect ratio of a conventional television screen, and a video having subtitles in a blank area in the display screen when played back in the conventional aspect ratio, In a video reproducing apparatus including a subtitle moving unit that moves a subtitle position, a comparing unit that detects a subtitle period in which a luminance level of a video signal is higher than a predetermined level, and the detected subtitle period is A subtitle period extending unit that extends the subtitle period forward and backward by a predetermined period with respect to the signal, and a synthesizing unit that synthesizes the video signal of the subtitle moving destination and the video signal of the subtitle portion based on the extended subtitle period. A video signal processing device comprising: