In print image, a watermark is an identifiable pattern which when viewed by reflected light seems to have different shades of lightness. In digital image, a watermark is a pattern, which is embedded in image to ensure the security and quality of an image. In this work, our main concern is design of energy efficient Watermark Generator (WMG) for video frame in order to gain extended life of the battery in the camera because the WMG is embedded into camera. We have assumed that target device is operating under five different frequencies and five different drive strength values. Low voltage Transistor-transistor logic (LVTTL) IO standard is used in this design to make it power optimized. This design is implemented on Kintex-7 FPGA, Device XC7K70T and -3 speed grades. When we are scaling the device operating frequency from 100GHz to 5GHz, there is 94.93% saving in total power of the watermark generator. It is also observed that when we scale down the drive strength from 24mA to 4mA, we achieve 3-4% saving in IO power of the target device.