JPS63196933A - Video window control system - Google Patents

Abstract

PURPOSE:To enable multiwindow display of video pictures by adding only partial software and an external device to general purpose work station and personal computer. CONSTITUTION:The timing of counting-up of the read address is adjusted in accordance with the reduction rate to generate video pictures corresponding to many kinds of reduction rate. For the purpose of displaying a reduced video picture in the position of a prescribed video window, coordinates (a, b) of the upper left corner of the video window and window information (w) and (h) are received by a read address generator 312. Window position information and window size information are compared with an output (y) of a raster counter 308 and an output (x) of a dot counter 310. The read address is generated to read out contents of a frame memory 307 only when both of formulas I and II are satisfied. The read-out video picture signal is sent to a picture switching device and is switched from/superposed on the output picture of the work station.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to display displays for personal computers and workstations, and in particular, displays in addition to characters and graphics.
The present invention relates to a video window display method suitable for displaying video images in multiple windows on the same screen.

[Conventional technology]

Generally, the display frequency of video images is in accordance with the NTSC standard, with a horizontal frequency of approximately 15.75 KHz and a vertical frequency of approximately 6 kHz.
On the other hand, many computers and workstations have horizontal frequencies set higher than the NTSC standard in order to improve the display quality of single characters and graphics.Video signals with different display frequencies In order to display the images on the same display device, it is necessary to share the display frequency of the plurality of video signals. As a frequency conversion device for this purpose, a digital scan converter (Sony DSC-10
) etc. This is the horizontal frequency 15 of the NTSC standard.
．． This converts a 75 KHz interlaced signal into a non-interlaced signal with twice the horizontal frequency (31.5 KHz). In such a device, 1
) The frequency to be converted is fixed, 2) There is no video size conversion mechanism, 3) The display does not have a partial display function, etc. For reasons such as
, 75 KHz, or double that 31.5K
It is not possible to display video images for non-Hz displays.

[Problem that the invention seeks to solve]

As mentioned above, with the conventional technology, 1) it is impossible to arbitrarily convert the display frequency, fl) it is impossible to convert the video display size, and
The first problem is that there is no partial display function that displays only a portion of the display. Therefore, it is difficult to display video images in multiple windows on the display of a personal computer or workstation.

The purpose of the present invention is to improve the above three points so that it can be displayed on the display in the same way as characters and graphics.

The purpose is to enable multi-window display of video images as well.

[Means for solving problems]

The first point of the above purpose, that is, arbitrary conversion of the display frequency, is
Digitize the video footage and write it into memory,
By reading it with a dot clock synchronized with the display frequency, frequency conversion can be realized.

The second objective, image display size conversion, is to thin out the read pixels according to the conversion ratio when reading the memory.
Alternatively, this can be achieved by double reading.

The third objective, partial display, can be achieved by reading out the memory in synchronization with the corresponding pixel clock of the partial display area of the display.

Multi-window display of video images is achieved by combining the above eight points.

〔Example〕

Embodiments of the present invention will be described below with reference to FIG.

Figure 1 is a diagram of a device constituting the present invention.
A workstation or personal computer with a multi-window display function,
Multimedia data such as characters, figures, images, etc. can be displayed in each window. Among these windows, the window that displays video images is called a video window (see Figure 2, 7), and window position information indicating its display position and window size information indicating its size are output to the outside of the workstation. Can be done. The window size information expresses the vertical and horizontal lengths of the window in terms of the number of pixels on the display.

An example of window position information is shown in Figure 92. 6 in the figure indicates a display, and the shaded area 7 is a video window.The video window has another window overlapping it from above, so its shape is Window position information, which is not necessarily rectangular, is expressed in a coordinate system in which the upper left corner of the video window is set at the upper left corner of the display and the number of pixels on the display is the unit (a, b in the figure).
) At the same time, as shown in the lower half of FIG. 2, a signal indicating whether a visible portion of the video window 7 exists is output for each raster of the display. This signal produces, for each raster, on outputs in synchronization with the pixel clock corresponding to pixels in the visible portion of the video window, and off outputs in synchronization with the pixel clocks corresponding to other pixels.

Reference numeral 2 in FIG. 1 indicates a device that generates a video image signal, such as a video disc player, a video tape device, or a TV tuner, that is, a video source.

3 in the figure is a device that converts the display frequency of the video image, and receives the above-mentioned window position information and window size information from the workstation 1, and a video image signal from the video source 2, and converts the display frequency of the video image. The display frequency of the signal is matched to the display frequency of the output video signal of the workstation, the video is reduced to match the size of the video window to be displayed, and the converted video is adjusted to fit the display position of the video window. It has the function of outputting video signals.

A detailed block diagram of this frequency conversion device is shown in FIG.
Reference numeral 301 in FIG. 3 inputs a video image signal (composite image signal) received from the video source 2 into a vertical synchronization signal vD1 and a horizontal synchronization signal HD.

Each subcarrier signal and luminance signal are separated into nine color information, and V
D s to the raster counter 302 , HD t to the raster counter 302 . The dot counter 304 is sent to the dot clock generator 303, and the luminance signal and color information are sent to the A/
Each is transmitted to the D converter 305.

Note that if the video image signal transmitted from the video source 2 is not a composite video signal but a synchronization signal separated from the luminance signal and color information, the function of the synchronization separator 301 is to For example, in the case of a composite sync signal system in which the synchronization signal is separated from the luminance signal, nine color information, but the vertical and horizontal synchronization signals are combined, the composite synchronization signal may also be used. In addition, the vertical synchronization signal V D
The function of the synchronization separation 11301 is to separate and output the horizontal synchronization signal HD 1 and the horizontal synchronization signal HD 1 .

If the input video image signal is in RGB format and the synchronization signal is superimposed on the G signal, from the G signal to VDi, HD
The function of the synchronous separator 301 is to separate and output i. Further, if the input video image signal is provided in a format in which the luminance signal, nine color information, each synchronization signal, etc. are all separated, the synchronization separator 301 is not necessary.

The luminance signal and color information separated by one as described above are digitized by the A/D converter 305 and written into the frame memory 307. The method for determining this write address will be explained next.

The raster counter 302 counts the vertical component of the write address, counts the horizontal synchronizing signal HD t, and is reset by the vertical synchronizing signal V D t. Note that if the input video image signal is of an interlaced format, the raster counter 302 counts one H.
It is assumed that the initialization by resetting V D t is performed by counting up by 2 every time D , and repeating 0 and 1 alternately so that it becomes 0 in the case of an odd field and 1 in the case of an even field. When the input video image signal is of a non-interlaced type, the count up by HD t is 1 at a time, and the initialization by V D i is also always O.

The dot counter counts the horizontal component of the write address to the frame memory 307, counts dot clocks generated by a dot clock generator 303, which will be described later, and is reset by the horizontal synchronizing signal HDs.

In dot clock generation @303, horizontal synchronization signal HD
A is input and a dot clock signal with a frequency four times that of the subcarrier signal is generated.The generated dot clock signal is sent to the above-mentioned dot counter 304, which generates the horizontal component of the write address. A/D converter 3
05 and provides the conversion frequency.

Write address generation @ 308 is generated by raster counter 302
A write address to the frame memory 307 is generated based on the vertical component of the write address counted by the dot counter 304 and the horizontal component of the write address counted by the dot counter 304, and sent to the frame memory 307.

As described above, the video image signal output from the video source 2 can be written into the frame memory 307.

This frame memory writing was executed based on the frequency of the video image signal from the video source 2.

In this way, the frequency of the video image signal is converted by reading out the contents written in the frame memory 307 based on the display frequency of the display to be output.

The read address is generated using the same method as when writing. That is, display synchronization signals (vertical synchronization signal VDo,
Based on the horizontal synchronization signal HDO), the raster counter 308
is the vertical component of the read address, and the dot counter 310
counts each horizontal component of the read address, and based on the count, the read address generator 312 generates an address. read from frame memory 307,
The video image signal after frequency conversion is sent to a D/A converter 311.
The signal is converted into an analog signal and displayed on the CRT 5 via the video switching device 4.

The timing of D/A conversion is determined by the dot clock generator 30.
given by 9.

The video image read from the frame memory 307 is
In order to display multi-windows on a TS, it is necessary to reduce the size of the video image. To achieve this, a method is adopted in which the pixel data on the frame memory 307 is thinned out and read out at a predetermined ratio depending on the reduction rate. That is, pixel data is thinned out by counting up the address of the frame memory 307 in synchronization earlier than the dot clock required for display. For example, video footage at 172
When reducing the number of pixels, the count-up of the read address is performed at twice the speed of the dot clock, and by reading out only the pixels that are synchronized with the dot clock, the number of pixels is thinned out by one pixel every two pixels. realizable. Similarly, two-thirds
When scaling down to 9 or more, the read address count up is 1.5 times the dot clock.
By adjusting the read address count-up timing according to the reduction ratio, video images compatible with various reduction ratios can be created.

In order to display the video image reduced as described above in a predetermined video window position, window position information,
That is, the read address generator 312 receives the coordinates (a, b) of the upper left corner of the video window and the window information (ω, h).

The read address generator 312 generates window position information,
Compare the window size information, the raster counter output y, and the dot counter output X, and find that a < x < a
Only when both formulas +ω a<y<b+h hold, a read address is generated and the contents of the frame memory 307 are read.

The read video image signal is sent to the image switching device 4, and a zero-order switching method in which switching/superimposition with the output image of the workstation 1 is performed will be described here.

The video switching device is composed of an analog switch. One of the inputs to the analog switch is.

One is the video signal from workstation 1, and the other one is the frequency converter l! This is the video image signal that is the output of No. 3. The control signal for switching between these two signals is the raster unit on/off signal in the window position information shown in the lower half of FIG. For each raster, the analog switch displays the video signal output from the workstation 1 on the CRT 5 when the on/off signal is off, and displays the video image signal on the CRT 5 when the on/off signal is on. .

The above method uses an analog switch, but there is also a method using an analog addition amount. In this method, in the workstation 1, the signal level inside the video window is set in advance to a pedestal level, and the display of the video window is switched without inputting window position information.

(Effects of the Invention) According to the present invention, it is possible to display a video image together with an output image from a workstation or a personal computer as one of multiple windows in any position and size. The required device is an external device for the workstation, and the workstation itself can be modified by simply making it possible to output window position information and window size information to the outside.This change also requires the above-mentioned steps. It is sufficient to output the information using an appropriate general-purpose interface, and to realize this, only a portion of software is added, and no hardware changes are required.

As described above, multi-window display of video images can be realized by simply adding some software and external devices to a general-purpose workstation or personal computer.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of window position information output by a workstation, and FIG. 3 is a block diagram of a frequency conversion device. 1...Workstation, 2...Video source,
3... Frequency conversion device, 4... Video switching device, 5.
・・CRT display bracelet.

Claims (1)

[Claims] 1. In a computer system that realizes multi-window display, a video source that generates a video image signal, a device that converts the frequency of the video image signal, a device that reduces the video image signal, and a display of the video image signal. 1. A video window control method comprising: a device for changing the position; and a device for switching and combining the video image signal and a computer output signal.