In this letter, we first propose a novel coding method to design content-adaptive H.264 steganography with quantized discrete cosine transform (QDCT) coefficients. Currently, the state-of-the-art steganographic methods minimize a heuristically defined distortion function using STCs and embed messages in a pixel-wise manner. When this concept is directly applied to H.264 steganographic designing, there are two factors that hinder the improvement of empirical security: interaction of embedding changes, and the block-wise characteristics of video compression. Our proposed CEC scheme performs both message embedding and video compression in the block-wise manner where a cluster of elements in a cover block are modified simultaneously, and defines a joint distortion function on the cover block to reflect the features of rate-distortion optimization. Experimental results demonstrate the effectiveness of our proposed coding method.

中文翻译：

---

CEC：H.264 隐写术的簇嵌入编码

在这封信中，我们首先提出了一种新的编码方法来设计具有量化离散余弦变换 (QDCT) 系数的内容自适应 H.264 隐写术。目前，最先进的隐写方法使用 STC 最小化启发式定义的失真函数，并以像素方式嵌入消息。当这个概念直接应用于 H.264 隐写设计时，有两个因素阻碍了经验安全性的提高：嵌入变化的交互，以及视频压缩的分块特性。我们提出的 CEC 方案以块方式执行消息嵌入和视频压缩，其中覆盖块中的一组元素同时被修改，并在覆盖块上定义联合失真函数以反映率失真优化的特征。