This document may be starting point to understand x264 and this documents good flaw will make you take nice deep in to x264 development. And come to x264 part, the x264 showed better quality than several commercial H.264/AVC encoders In this paper, performance of the JM encoder (ver. 10.2) with x264 (ver 0.47.534) is also compared and shown that x264 is about 50 times faster and provides bitrates within 5 of JM for the same PSNR.-This　document may be starting point to understand x264 and this documents good flaw will make you take nice deep in to x264 development. And come to x264 part, the x264 showed better quality than several commercial H.264/AVC encoders　In this paper,　performance of the JM encoder (ver. 10.2) with x264 (ver 0.47.534) is also　compared and shown that x264 is about 50 times faster and provides bitrates within 5　of JM for the same PSNR.