Enhanced presentation of sub-picture information

Abstract

A system is provided for processing video images for display. In one example, the system comprises a stream parser for retrieving a compressed main video data and a sub-picture identifier. A video decoder generates a main video image having a main video intensity value for each pixel in the main video. A sub-picture decoder determines a sub-picture image based on the sub-picture identifier. The sub-picture image includes a pixel data for each pixel in the sub-picture image indicative of a sub-picture pixel type including a background pixel type and a pattern pixel type. Each pixel includes a command code indicative of a background contrast level, a pattern contrast level, a background color level and a pattern color level. An intensity formatter generates a sub-picture pixel intensity for each pixel in the sub-picture image. A preprocessing function calculates, for each sub-picture pixel, a sub-picture pixel intensity by alpha-blending the sub-picture pixel with no main video pixel when the background color intensity is greater than the pattern color intensity. A filtering function performs anti-aliasing filtering on the sub-picture image. A sub-picture alpha-blending function combines the sub-picture image with the main video image using alpha-blending.