| 摘要 |
Color video data is compressed by storing only the most frequently occurring colors in a block of pixel data. A minimum number of colors for the block is determined determining when colors in a block are the same or comparatively close to colors in the corresponding block of the previous video frame or are comparatively close to colors in the next previous adjacent block such that no additional color data needs to be stored, and by consolidating comparatively close colors withing the block. Two comparatively close colors are consolidated by substituting the more frequently occurring color for the less frequently occurring color in the block. Colors are comparatively close when the difference in their color values is less than a color threshold value. The color threshold value can be set by the user. If the minimum number of colors determined for the block is greater than four, then the color thresholds are adjusted and a new minimum number of colors is then determined. The pixel data of the block are stored in accordance with the minimum number of colors determined for that block. Greater compression is achieved when a lower minimum number of colors is determined for the block. Further compression can be achieved by incorporating a reference to a buffer containing common colors, and using a flag stored in the video stream to indicate when the data included in a byte of color data is an index value pointing to a color stored in the buffer rather than actual color data. |
