JP2630282B2 - Digital video playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital moving picture reproducing apparatus for reproducing digital moving picture data in which a color moving picture signal is recorded in a digital system, and more particularly to a digital moving picture reproducing apparatus provided with a pallet on a display device such as a personal computer. About.

[0002]

2. Description of the Related Art Generally, in this type of apparatus, image data recorded in a digital system and stored in an external storage device such as a hard disk or a CD-ROM is stored in a main storage device (R).
AM), convert it to a format compatible with the display device,
The data is transferred to the storage device (VRAM) for the display device. The display controller displays data on the VRAM on a display device. The moving image data is composed of a series of image data for one screen (frame) recorded along the time axis, and the digital moving image reproducing apparatus continuously synchronizes these frames with the time axis to the display device. To play the moving image.

Each frame is composed of colored pixels arranged vertically and horizontally on a grid. To represent pixels digitally, the RGB format is widely adopted. R
In the GB format, each of R (red), G (green), and B (blue) components of a pixel is represented by quantizing its luminance to a specific number of bits. As an example,
By allocating 8 bits to each of R, G, and B, it is possible to express a color of 24 bits (about 16 million colors) per pixel.

On the other hand, in a display device such as a personal computer, a method of performing color display with a small storage capacity by using a pallet is widely used (Japanese Patent Laid-Open Publication No. Hei 0 (1999)).
4-350895, JP-A-61-184589). As an example, a palette table having 256 palettes that can specify 24-bit colors is provided.
The index to the palette table is stored, and the display controller causes the display device to generate a color specified in the palette corresponding to the index of the palette table for each pixel in the VRAM, thereby allowing each pixel to be displayed. There is a device that generates an arbitrary 256 colors from about 16 million colors with a storage capacity of 8 bits.

In such a display device, in order to reproduce digital moving image data recorded in full color (approximately 16 million colors), the colors of the digital moving image data are adjusted to the maximum number of display colors (256 colors) of the display device. Therefore, it is necessary to reduce the color of the image data. Therefore, an appropriate 256 colors are designated in advance in the palette table, and when the digital moving image data is transferred to the display device, each pixel is converted into the closest color in the palette table, Perform color reduction processing. In general, palletizing processing is performed to designate colors in the palette table in advance. As an example of the palletizing process, there is a method of examining the distribution of colors recorded in digital moving image data to be reproduced and assigning the most frequently occurring colors to pallets in descending order. By performing the palletizing process in this manner, an image can be reproduced in a color closer to the original color recorded in the digital moving image data.

[0006]

Generally, since a large amount of calculation is required for the palletizing process, it is inefficient to perform the palletizing process at the time of reproducing each frame. Therefore, this type of conventional digital video playback apparatus performs a palletizing process on an appropriate frame of the digital video data before playing the digital video data, and uses a fixed pallet table having the same content in a plurality of frames. Playing digital video. However, in general, the color distribution of digital moving image data has a bias for each frame, and when a fixed palette is used, there is a problem that sufficient colors cannot be reproduced for all frames to be reproduced. . In addition, it is necessary to select an appropriate frame for performing the palletizing process, which requires human operation and judgment.

SUMMARY OF THE INVENTION It is an object of the present invention to automatically obtain a palletizing timing at which a digital moving picture reproducing apparatus can efficiently obtain an appropriate palette while reproducing a moving picture.

[0008]

SUMMARY OF THE INVENTION The present invention provides a moving picture reproducing means for reproducing digital moving picture data in which a full-color moving picture signal is recorded in a digital system on a display device having a palette, and a digital moving picture data to be reproduced. , One
Palletizing means for generating an appropriate palette table from data for frames, and digital video data
Frame acquisition means for successively acquiring image data for each frame; and for each image of image data for one frame, a distance in the RGB color space between a palette color and a pixel color from a palette table is fixed. A pallet search unit for searching a pallet equal to or less than the threshold value, a mishit counting unit for counting the number of pixels for which search by the pallet search unit has failed for each pixel of image data for one frame, Pallet update notification means for notifying the palletizing means of a pallet update timing when the number of pixels counted by the mishit counting means becomes equal to or more than a certain value.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A digital moving picture reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a digital moving picture reproducing apparatus according to this embodiment.

This apparatus comprises a CPU 100, a main storage device (R
AM) 110, VRAM 120, pallet table 13
0, display controller 140, external storage device 1
50 are connected by a BUS 170. The display device 160 is connected to a display controller. The RAM 110 stores a program for controlling the apparatus and data. The CPU 100 controls the entire device according to a program stored in the RAM 110. The external storage device 150 stores full-color digital moving image data. The VRAM 120 stores image data to be displayed on the display device 160. The palette table 130 is a table for referring to color information (palette) of pixels, and stores 256 palettes. V
The image data stored in the RAM 120 is stored in the form of an index value for a palette in the palette table 130. The display controller is a VRAM 12
0, and an image is displayed on the display device 160 based on the contents stored in the pallet table 130.

FIG. 2 is a data flow diagram of the digital moving picture reproducing apparatus.

The frame acquisition means 200, the pallet search means 210, the miss hit counting means 220, the pallet update notifying means 230, the palletizing means 250, and the moving picture reproducing means 270 are provided by the present apparatus stored in the main storage device (RAM) 110. This is the module of the program to be controlled.
The digital moving image data 240 is 30 per second along the time axis.
Frames recorded on a frame-by-frame basis are stored consecutively in chronological order. In each frame, pixels are arranged on a grid by 160 dots vertically and 320 dots horizontally. Each pixel stores color information of the pixel in a 24-bit RGB format. The frame obtaining means 200 synchronizes with the video playback of the video playback means 260 and
Digital moving image data is acquired one by one from 0 to 1 frame and passed to the palette search means 210. The pallet search unit 210 searches for the closest color pallet from the pallets in the pallet table 130 for each pixel of the data of each acquired frame, and passes the pallet to the mishit counting unit 220. The closest color is a color with the shortest distance in the RGB color space. The RGB color space is R,
In a three-dimensional space with each axis of G and B, each coordinate is 0
This is a discrete space taking an integer value of ~ 255. In the RGB space, a color is represented as a combination of R, G, and B values, that is, a point. For example, the pixel color D (R1, G1, B
1) and palette color P (R2, G2, B2 distance on RGB space) | D-P | ^{is, (R1-R2) 2 +} (G1-G
^{2) 2 + (B1-B2} ) is calculated by the square root of ^2. The miss hit counting means 220 counts the number of pixels for which the distance between the color of the searched palette and the color of the actual pixel in the RGB color space is equal to or larger than a certain value for each pixel. Hand over to 230. That is, the pixels in which no color close to the original color of the pixel exists in the palette table are counted. The pallet update notifying means 230 notifies the palletizing means 250 of the pallet update timing when the number of mishit pixels exceeds a certain value. The palletizing means 250 includes a pallet update notifying means 230.
Receives the notification of the pallet update timing from the digital video data 2
40, the palletizing process is performed, and the pallet table 130 is updated. The moving image reproducing means 260 converts the full-color image data of the digital moving image data 240
After the color is reduced to 256 colors based on the contents of the palette in the palette table 130, the image is displayed on the display device 160.

[0014]

According to the present invention, the timing of palletizing can be automatically obtained while the digital moving picture reproducing apparatus is reproducing a moving picture. That is, an appropriate pallet can be efficiently obtained without requiring any operation or judgment by a person.

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital moving picture reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a data flow diagram of the digital moving picture reproducing apparatus shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 CPU 110 Main storage device (RAM) 120 VRAM 130 Palette table 140 Display controller 150 External storage device 160 Display device 200 Frame acquisition means 210 Pallet search means 220 Mishit counting means 230 Palette update notification means 240 Digital video data 250 Palletizing means 260 Video playback means

Claims (3)

(57) [Claims] 1. A digital moving picture reproducing apparatus having moving picture reproducing means for reproducing digital moving picture data in which a full-color moving picture signal is recorded in a digital system on a display device having a palette, wherein one of the digital moving picture data to be reproduced is Palletizing means for generating an appropriate pallet table from data for frames, frame obtaining means for sequentially obtaining image data for each frame from digital video data, and for each pixel of image data for one frame, Palette search means for searching a palette in which the distance between the color of the palette and the color of the pixel from the palette table in the RGB color space is equal to or less than a certain threshold value, and for each pixel of the image data for one frame, A mishit counting means for counting the number of pixels which failed to be searched by the pallet search means, Digital moving picture reproduction, comprising: a pallet update notifying means for notifying the palletizing means of a pallet update timing when the number of pixels counted by the mishit counting means becomes equal to or greater than a certain value. apparatus. 2. The digital moving picture reproducing apparatus according to claim 1, wherein the pallet table stores the pallets in 25.
A digital moving picture reproducing apparatus, wherein six digital moving pictures are stored. 3. The digital moving picture reproducing apparatus according to claim 1, wherein said moving picture reproducing means, said frame obtaining means, said pallet searching means, said mishit counting means, said pallet updating notifying means, and said palletizing means are main storages. A digital moving picture reproducing apparatus, which is a module of a control program stored in the apparatus.