a traffic density analysis method includes decoding encoded video data corresponding to an analysis region to obtain a decoded video signal and code information , determining a moving object in units of a macroblock on the basis of the decoded video signal , the code information and a previously decoded video signal , analyzing a macroblock determined as the moving object , setting a specific region in a screen using an analysis result of the macroblock , and estimating a traffic density in the analysis region from information related to the moving object passing through the specific region .