Complexity-based rate control using adaptive prefilter

摘要

In an image capture device, a filter in a processing stage prior to an MPEG encoder applies unsharp masking and spatial filtering. MPEG encoder hardware that is used to determine SAD values also determines a complexity value. The complexity value indicates a complexity of a macroblock or a frame. The processor uses the complexity value to determine an appropriate transfer function of the spatial filter. The spatial filter smoothes information supplied to the MPEG encoder such that the MPEG encoder can apply less severe quantization, thereby reducing apparent block noise when the resulting MPEG video is later decoded and viewed on a display device.