随着信息技术的快速发展，压缩编码已成为多媒体存储和传输领域的研究热点。针对视频压缩的编码效率问题，ITU T与ISO/IEC两大标准组织于2003年联手推出了H.264/AVC视频编码标准。为了能够在目标带宽上有效地传输视频，就必须合理地控制码流的波动强度，以使其尽可能地接近目标带宽。其中码率控制虽然不是标准中的一部分，但由于其一直在视频编码标准的发展过程中占有举足轻重的地位，为此，针对H.264/AVC编码的视频序列码率控制问题，在JVT G012算法的基础上，提出了一种基于STGS图的自适应地选择基本单元大小的码率控制算法。该算法在编码时产生的码率波动总是与G012算法产生的最小码率波动相当。而且具有较小的运算复杂度，易于实时实现。

With the rapid development of information technology, compress coding has become a heated topic in the field of multimedia storage and transmission. Aiming at the coding efficiency of video compression, ITU T and ISO/IEC jointly developed a new video coding standard named H.264/AVC in 2003. In order to transmit video efficiently on certain bandwidth, the rate fluctuation should be controlled to make it as close to the target bandwidth as possible. Although rate control is not a part of the standard, it has been playing an important role in the standard all the time. For this purpose, on the basis of JVT G012 algorithm, a new rate control algorithm based on Spatial Temporal Gradient Scale (STGS) image is presented for H.264/AVC coding to select the size of basic unit adaptively. The rate fluctuation resulted from the proposed algorithm is always close to the best case of JVT G012 algorithm. Moreover, for the low computational complexity, the proposed algorithm is easy to implement in real time applications.