Patent attributes
A video compression encoder which does not require a video frame buffer is disclosed. Without a frame buffer, incoming pixels can not be compared to pixels previously sent to the decoder. Instead, the disclosed encoder only stores check values for groups of pixels sent. If a group's check value has not changed, the encoder sends a command to the decoder not to change that pixel group. Also, without a frame buffer, an incoming video frame can not be captured and later sent to the decoder as network throughput permits. Instead, if throughput is insufficient to send an encoded group of pixels, the encoder leaves the check value for that group unchanged and sends a command instructing the decoder not to change those pixels. This defers updating that group until the next screen update is sent to the decoder. Grouping of pixels can be done in any fashion, for example; a group can be a single video line, a portion of a line, multiple lines or screen rectangles containing portions of multiple lines.
