Abstract: A method for modulating one or more fields of video signal (18) with auxiliary signal (20) by use of an encoding improvement, the one or more fields having one or more sub-fields, the one or more sub-fields having a plurality of odd and even scan lines, the plurality of odd and even scan lines having a plurality of pixels, the plurality of pixels each having an intensity comprising obtaining on encoder (12) the video signal from signal source (10), selectively designating on encoder the plurality of odd and even scan lines as up lines or down lines for at least one of the one or more sub-fields for at least one of the one or more fields, calculating an amount of intensity adjustment for the pixels of the plurality of odd and even scan lines on encoder, and adding intensity to the up lines and subtracting intensity from the down lines according to the amount of intensity adjustment for the pixels of the scan lines of video signal on encoder.

Abstract: A method for encoding a carrier signal in a video signal, the video signal having one or more frames, the frames each having a first field and a second field, the first field and the second field of each frame having a plurality of scan lines, each having a plurality of pixels with an intensity value indicating brightness, the method comprising selectively designating the plurality of scan lines of the first field of the one or more frames as up lines or down lines, calculating an optimum amount of adjustment to the pixels of the up lines and the down lines, and selectively increasing the intensity value of pixels of the up lines and decreasing the intensity value of pixels of the down lines by the optimum amount of adjustment thereby modulating the video signal with a carrier signal and creating a modulated video signal.