NVIDIA Corporation
TRANSFER OF VIDEO SIGNALS USING VARIABLE SEGMENTED LOOKUP TABLES

Abstract:

The disclosure is directed to transforming signals from one signal format to another signal format. For example, the format of a digital signal can change from storing video information in 12 bits of data to storing the video information in 32 bits of data. Other storage values and combinations can also be used. Since the number of bits available to store a portion of the video information can change when changing formats, a process is needed to translate or transform the video information appropriately. A transfer function utilizing a lookup table is used for the transforming. The lookup table utilizes a variable step size segmentation scheme that decreases the amount of lookup table storage space required and also decreases the number of estimation errors, i.e., interpolation errors. Estimation errors can occur when looking up a value not stored in the lookup table, and using neighboring values that are stored to estimate the value requested. In some applications, the log.sub.2 step size or total size values can be stored in the lookup table to further reduce the amount of storage space required. A video parameter, such as the type of video content and the display room ambiance, can also be used to select the balance between further decreasing the size of the lookup table and further decreasing the estimation errors.