Gop structure adaptive to the video content for efficient H.264/AVC encoding

This paper presents a new method for high efficiency video coding using an adaptive GOP structure based on video content for the H.264/AVC standard. The available H.264/AVC encoders typically use static GOP sizes that define how the frames I (Intra), P (Predictive) and B (Bi-predictive) are positioned during de coding process. However, by analyzing the video content it is possible to identify the optimum position for each type of frame inside the GOP. The proposed method analyses the video content and finds the best position for inserting I frames in the video sequence. Thus the GOP structure can assume different sizes, depending on the video content. The results for test sequences and real videos show that the proposed method can significantly reduce the required bit rate, comparing to the static GOP sizes, with reduced PSNR losses. The proposed adaptive GOP presents a gain, in terms of bit rate reduction for real movies, of 8.6%, 15%, 24.7% and 40.8% in comparison with static GOP sizes 32, 16, 8 and 4, respectively.