CAMSHIFT algorithm and Comaniciu/Meer algorithm are two fundamental frameworks of mean shift procedure for video target tracking. This paper generalizes the two well-known mean shift tracking algorithms, originally due to Bradski and Comaniciu/Meer. A new general similarity function which defines the distance between the target model and target candidate is employed to calculate the pixel weights and the target location. The target size is iteratively estimated and updated based on the zeroth order moment of the pixel weights. Then we prove that both the CAMSHIFT algorithm and the Comaniciu/Meer algorithm can be included in the generalized mean shift tracking framework. The tracking performances of three mean shift algorithms in the unified framework are shown and compared in the experimental results.