System and process for broadcast and communication with very low bit-rate bi-level or sketch video

A computer-implemented process for generating a bi-level video, comprising using a computer to perform the following process actions:

• inputting digitized video comprising a sequence of video image frames;
• converting the input video image frames into bi-level image frames, wherein the digitized video is characterized by pixels defined in terms either a color level or a gray scale level, and wherein said conversion comprises,
• ascertaining whether the input video image frames comprises pixels defined in terms of a color level, and
• converting each input video image frame so as to define each pixel thereof in terms of one of a plurality of gray scale levels so as to produce a gray scale image frame whenever the pixels are defined in terms of color levels, wherein the particular gray scale level selected to define a pixel is based on the color level of that pixel, such that for each bi-level image frame, this converting comprises,
• computing a threshold gray scale level,
• assigning a first of two bi-level image frame colors to those pixels that exhibit a gray scale level exceeding said threshold by a prescribed upper-limit amount,
• assigning the second of said two colors to those pixel exhibiting a gray scale level that is less than said threshold by a prescribed lower-limit, and
• associating an indicator with those pixels that exhibit a gray scale level which does not exceed said threshold by the upper-limit amount and which are not less than said threshold by the lower-limit amount, wherein one of the two bi-level image frame colors is assigned to the pixels having said indicator associated therewith based on a predicted value established for the pixel as part of the performance of the process action for encoding the bi-level image frames;
• and
• encoding the bi-level image frames.