Video fingerprinting using watermarks is described herein. A watermark encoder embeds a watermark into an input video to produce a watermarked video. The watermark encoder can choose particular regions of the video that are sufficiently complex for watermarking. Spatial and temporal complexity analyses can be performed on a per-pixel basis to locate suitable regions of the video. The watermarks can be embedded using a unique codeword associated with a given user. A watermark decoder can receive the watermarked video. In some instances, the watermarked video may have been attacked in some way after being output by the watermark encoder. In these instances, the watermark decoder can extract the watermark from the watermarked video. In turn, the watermark decoder can extract the codeword from the watermark, and compare the extracted codeword to a plurality of known codewords associated with respective users.