JP3183231B2 - Bus transfer method for video data - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video display system for displaying an interlaced video signal, for example, a video signal of a TV (television), LD (laser disk) or the like on a non-interlaced display device of an information processing apparatus. In particular, the present invention relates to a method for displaying video data on a display device of a system via a system bus.

[0002]

2. Description of the Related Art An image such as a TV or an LD has an interlaced display format in which even-numbered scanning lines and odd-numbered scanning lines are alternately displayed every 1/60 second. The even-numbered scanning lines are referred to as “odd (Odd) fields”. The two of the even and odd fields are collectively called a "frame".

In an information processing apparatus such as a personal computer, an interlaced video signal (TV, LD
Etc.) and display them on a non-interlaced display device.

In such a case, a technique called overlay is required, and several methods are used to perform the overlay.

In the first system, as shown in FIG. 5, a video signal including a video input 54, a video display device 55, and a buffer 56 is provided separately from a system display path including a system bus 51, a system display device 52, and a buffer 53. Are prepared, and an overlay is performed by switching the display changeover switch 57 at the final stage of the display.

In the second method, as shown in FIG. 6, data from a video input 64 is supplied to a buffer 63 of a system display device 62 via a system bus 61, and an overlay is provided only by a system display path. Is a method for realizing.

[0007]

In the first method, the video display path and the system display path are independent from each other even if the overlay is performed, so that the performance of the entire system is not affected. There is a problem that it is difficult to control the timing of the switch 57 in the last stage.

On the other hand, the second system does not require switch control at the final stage of display, and requires a simpler circuit configuration than the first system. However, video data is transmitted via a system bus. Because it is displayed, it greatly affects the performance of the entire system.

[0009] In the system of the second system, video data must be periodically transferred to the system bus. Further, it is necessary to always transfer a certain amount of data. If the use of the system bus cannot be secured on a regular basis, there is a problem that frames are dropped from the video screen, and the motion becomes less smooth.

[0010] Further, the system bus of the present personal computer is configured such that while one of the devices connected to the system bus uses the bus, other devices cannot be used. Therefore, if the system bus is occupied regularly for video display, the performance of the system will necessarily decrease.

In displaying video data, the field data must be updated every 1/60 second on average.
Here, the average is 1/60 second because the screen update frequency on the system display side may be different from the screen update frequency of a signal such as a video. Therefore, 1
It is necessary to secure the system bus periodically every / 60 seconds.

For video data, for example, 20
MByte (megabyte) / sec data transfer must always be performed.

As a general system bus of a present personal computer, for example, a PCI (Peripheral Com
ponent Interconnect) bus is used, but the data transfer capacity of this bus is 132 Mbytes / sec at the maximum.

However, in a normal operation state, depending on the load connected to the system bus, the data transfer capability is at most about 50% to 60% of the maximum value at present.

In addition, this type of LSI which is currently being announced
Cannot perform buffer control performed by a dedicated LSI or the like for processing a video signal, and therefore must be written in a buffer on the system display side in synchronization with input timing of video data.

For example, a publication (Philips Semiconductors)
DATA HANDBOOK IC22, July 1995
Mon, P653-654, “Multimedia bridge scaler a
nd PCI circuit ").

In general, the system display side does not have a function of performing field display on such a video input signal, and therefore performs a frame display.
"Motion Artifac
t), a phenomenon occurs in which the contour line due to the movement of the interlace inter-field time difference looks jagged.

Further, in the conventional system, no means for reducing the data transfer amount is considered.

Therefore, the present invention has been made in view of the above problems, and reduces the occupation rate of a system bus during video data transfer and generates motion artifacts in frame display. It is an object of the present invention to provide a video display system that avoids the above.

[0020]

In order to achieve the above object, the present invention stores interlaced video data in a buffer of a non-interlaced image display device via a system bus and displays a video image. in the system, a frame buffer, it is only a difference between the previous screen and transfers the system bus, the input i
From the interlaced video signal, the current field information and the previous file
Difference detection means for detecting difference information between the field information
A difference between the fields is a predetermined threshold
For the area exceeding the maximum value, the current field information is
Interpolation means for generating current display frame information by interpolating based on
And further comprising:
Between the display frame information and the previous display frame information
Differences are detected and only the differences between the frames are
To the non-interlaced display means.
A video data transfer method for performing video display, wherein
In which the difference between the thresholds is less than a predetermined threshold.
As for the area, the interpolation means outputs the current field information.
From the previous display frame information and the current display frame.
Generating frame information .

The outline of the present invention will be described below. The present invention creates an input interlaced video, a difference between fields, and new frame information obtained by interpolating from a previous display frame information, and generates only a difference from the previous display frame information on a system bus. To perform frame display.

According to the present invention configured as described above, the motion artifact (Motion Artifac)
t) is not displayed, and the system bus occupancy can be reduced.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. In a preferred embodiment of the present invention, the video data transfer system comprises: difference detecting means for detecting difference information between current field information and previous field information from an input interlaced video signal; For an area in which the difference value exceeds a predetermined threshold, interpolation means for generating current display frame information by interpolating based on the current field information is further provided. The difference between the frames of the current display frame information and the previous display frame information is detected, and only the difference between the frames is transferred to the system bus to display the frame on the non-interlaced display means.

Then, for an area in which the difference value between the fields is equal to or less than a predetermined threshold value, the interpolation means calculates the current field information, the previous display frame information,
To generate current display frame information.

In a preferred embodiment of the present invention, there is provided a frame buffer for storing previous field information and current field information, and previous display frame information and current display frame information as current display frame information. The field information and the current field information, and the previous display frame information and the current display frame information are respectively subjected to double buffering control.

A personal computer suitable for the present invention generally includes an input unit for inputting interlaced video data, a display device for displaying non-interlaced video data, and a system for transferring video data. And a transfer system having the above function can be used as the transfer system. Next, embodiments of the present invention will be described with reference to the drawings.

An embodiment of the present invention will be described below with reference to the drawings in order to describe the above-described embodiment of the present invention in further detail. FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention. FIG. 2 is a diagram showing a detailed configuration of a portion surrounded by a broken line in FIG.

Referring to FIG. 1, video data from a video input 110 is converted from an analog signal to a digital signal by a video decoder 101 and separated into a luminance component and a chrominance component. The video data converted to a digital signal is
The video information input unit 102 allows the frame buffer 105
Is written to the update field buffer 121 (see FIG. 2) and at the same time is sent to the difference detection unit 103.

The difference detection unit 103 includes a video input unit 102
Reads the display field buffer for which writing has been completed in the frame buffer 105 and calculates the difference between the display field buffer and the field information sent from the video information input unit 102. That is, the difference from the next field is calculated.

The moving body in the screen is detected by the difference calculation. The difference information is sent from the difference detection unit 103 to the interpolation unit 104.
Is sent with the field data.

From the result of the detection, the interpolating unit 4 interpolates the moving object from the display field information, as shown in FIG. Interpolation is performed using both display frame information and field information.

In the interpolation unit 104, interpolation is performed to create display frame information, which is sent back to the difference detection unit 103 and, at the same time, written into the current display frame buffer 124.

The difference detection unit 103 calculates the difference between the display frame information sent back from the interpolation unit 104 and the data read from the previous display frame buffer 123, and only that part is converted to the color space conversion unit 106 or the image. The information is sent to the information transfer unit 107.

FIG. 3 schematically shows data processing from input of video data to display. In FIG. 3, the numbers added after the notation “Oddn” / “Even” indicate the temporal order.

In FIG. 3, the input video data is
"Odd0" is followed by "Even0".

Also, in the current display frame and the previous display frame, “break” added after “Odd” or “Even” is shown in FIG. As described above, since interpolation is performed using both the previous frame information and the current field information,
Since the meaning is different from the original field information, the description is given after distinction. FIG. 3 shows the contents stored in each buffer for each 1/60 sec clock.
The update field buffer 121, the display field buffer 122, the current display frame buffer 1
24, the previous display frame buffer 123 is shown in order. now,
Assuming that the first input data of the first-stage update field buffer 121 is Odd0, the first stage has Odd0 = Even0 =
Odd1 = Even1 = Odd2. By double buffer control, the storage data of the first stage is
At the next timing (2/60 sec), it is moved to the second-stage display field buffer 122. First time (1
/ 60 sec), the stored contents in the second row are arranged as E
ven-1 = Odd0 = Even0 = Odd1 = Even1. At the first time, a difference between the input data (Odd0) and the data (Even-1) in the display field buffer 122 is detected by the difference detection unit 103, and the interpolation data (Even-1 modified, Odd0) is detected.
) Is created and stored in the current display frame buffer 124. (On the other hand, at the same time, the difference between the interpolated data and the data in the front table frame buffer is detected.) At the next clock timing (2/60 sec), the interpolated data (even-1 revised, Odd0 revised) is replaced with the previous display frame buffer. Moved to 123. At this point (2/60 sec), the next interpolation data (Even
0 break, Odd 0 break = data of current display frame buffer 124) and data of previous display frame buffer 123 (Eve
n-1 and Odd0), and the detected frame difference is transferred. Hereinafter, the same process is repeated.

Next, the color space conversion unit 106 is configured to pass if the system display device such as the graphic accelerator sent from the video information transfer unit 107 has a color space conversion function. I have.

Note that the four buffer areas in the frame buffer 105 are
1 and the display field buffer 122, and the previous display frame buffer 123 and the current display frame buffer 124 are switched and updated by double buffer control.

[0039]

As described above, according to the video display device of the present invention, even when video data is transferred via the system bus, the occupancy of the system bus can be reduced.

Further, according to the present invention, even if an interlaced video is displayed in a frame, a shift in the motion of the time difference between the fields is seen as a video (Motion A).
rtifact) can be made less visible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram illustrating details of a configuration of a frame buffer according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of one embodiment of the present invention, schematically showing a change in the contents of each buffer and an order in which the contents are used to reach display.

FIG. 4 is a diagram schematically showing an interpolation method of an interpolation unit 4 according to one embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a first conventional method for realizing an overlay technique.

FIG. 6 is a diagram showing a configuration of a second conventional method for realizing an overlay technique.

FIG. 7 is a diagram showing an example of a unit configuration of a computer device incorporating the present invention.

FIG. 8 is a block conceptual diagram of an example of a computer device incorporating the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 101 video decoder 102 video information input unit 103 difference detection unit 104 interpolation unit 105 frame buffer 106 color space conversion unit 107 video information transfer unit 109 system bus 110 video input 111 graphic accelerator 112 graphic memory 113 display device 121 update field buffer 122 Display field buffer 123 Previous display frame buffer 124 Current display frame buffer

Claims (6)

(57) [Claims] 1. A difference detecting means for detecting difference information between current field information and previous field information from an input interlaced video signal, and a predetermined threshold for determining a difference value between the fields. Interpolating means for generating a current display frame information by interpolating based on the current field information for an area exceeding the value, further comprising: detecting a difference between frames of the, film performs frame displayed on the display means of the non-interlaced and transfers only the difference between the frame to the system bus
An image data transfer method, wherein a difference value between the fields is a predetermined threshold value.
For the following areas, the interpolation means
Interpolation from the field information and the previous display frame information.
A video data transfer method for generating current display frame information . 2. A pre-field information and the current field information, previous display frame information and forwarding system of the video data according to claim 1, further comprising a frame buffer for storing the current display frame information. 3. The frame buffer according to claim 2, wherein the previous field information and the current field information, and the previous display frame information and the current display frame information are respectively subjected to double buffering control. The described video data transfer method. 4. An input unit for inputting interlaced video data, display means for displaying non-interlaced video data, and a system for transferring video data, wherein the transfer system comprises: Difference detecting means for detecting difference information between the current field information and the previous field information from the interlaced video signal, and for a region where the difference value between the fields exceeds a predetermined threshold value, wherein generating the current display frame information by interpolation based on the current field information, the field
Region where the difference value between them is equal to or less than a predetermined threshold value.
The current field information and the previous display frame
And interpolating means for generating current display frame information by interpolating from the information , further comprising: a difference detecting means for detecting a difference between frames of the current display frame information and the previous display frame information, Transferring only the difference between the frames to the system bus and performing frame display on non-interlaced display means,
A personal computer, characterized in that: 5. The personal computer according to claim 4, further comprising a frame buffer for storing previous field information and current field information, and previous display frame information and current display frame information. 6. The said frame buffer, the previous field information and the current field information, and the previous display frame information and the current display frame information, according to claim 5, each double buffering control, it is characterized by
The personal computer as described.