Methods and apparatus for statistical multiplexing in a dual pass encoding scheme are provided. A first pass encoder encodes alternate slices of anchor frames as I-slices and P-slices respectively in order to generate statistics for both I and P frame encoding for the same anchor frame. A second pass encoder determines the encoding complexity estimates for a plurality of frames in a look-ahead pipeline and sums the encoding complexity estimates of selective frames in the look-ahead pipeline to determine the initial need parameter for a current frame to be encoded. The second pass encoder computes a need parameter for encoding the current frame based on the initial need parameter. The need parameter is used by a statmux processor to determine the encoding bit rate for second pass encoding of the current frame.