Patent ID: 7675970

Claim:
A method of processing a bitstream in a digital video transcoder, comprising: (a) determining an adjustment factor that is a ratio of a number of bits representing a selected frame defined by said bitstream to a target number of bits for said selected frame; (b) determining an average spatial activity value among sets of video data associated with said selected frame; (c) determining a spatial activity value for a selected set of said sets of video data; and (d) computing a normalized spatial activity value for said selected set of video data in response to said average spatial activity value, said spatial activity value, and a function of said adjustment factor; wherein said normalized spatial activity value is computed using a second function, defined by: N_act j = f ⁡ ( rcFactor ) × act j + avg_act act j + f ⁡ ( rcFactor ) × avg_act , where j represents said selected set of video data, N_act j is said normalized spatial activity, rcFactor is said adjustment factor, f is said function of said adjustment factor wherein f is not a constant function, act j is said spatial activity value, and avg_act is said average spatial activity value.