H.264是近年來所新發展的影像壓縮技術,其壓縮效能以及影像畫質都超越了以往的技術,由於H.264的高壓縮效能,使得影像能夠在網路上輕易地傳播,因此影像版權的問題也將是H.264所要考量的一個重要議題。在這裡,我們提出的解決方式是在影片中加入浮水印。 由於H.264是利用差餘區塊來做編碼,因此大部份量化之後的區塊皆為全零區塊,而這些全零區塊也是讓H.264壓縮效率高的一大主因。所以本篇論文提出的方法主要是盡量保有現有的影像品質以及全零區塊,修改部份離散餘弦轉換並經由量化區塊的值,來達到數位浮水印的效果,而修改低頻部份的數值,對人眼視覺會造成比較大的影響,因此我們僅修改中高頻的部份。
In recent years, H.264 is a new video compression technology. Its compression and the video quality exceed in the previous technology. H.264 high compression efficiency makes video can easily spread on the Internet so that the copyright issue will be considered an important topic for H.264. Here, we propose a method to embed the watermark into H.264/AVC. Due to the use of residual block coding of H.264, most of the blocks after quantization are all-zero blocks, These all-zero blocks is a high compression efficiency of a major culprit for H.264. Therefore, the main idea of this paper is to keep the existing video quality and the all-zero blocks. We change part of quantized DCT (discrete cosine transformation) coefficients to embed digital watermark. It will cause large effect for human vision to modify the low frequency so that we only modify to the middle-frequency domain and high-frequency domain.