本論文提出一個以數位影音視訊檔案為載體之高容量機密資訊隱藏機制。近年來由於網際網路的蓬勃發展以及許多影音社群平台的流行，在網路上觀看傳播高畫質數位串流影音媒體更加便利。高畫質檔案多以FLV 格式且以H.264/AVC編碼為大宗，其音訊則以MPEG AAC編碼為主流。本研究充分地利用了高畫質編碼技術之細節特徵資訊，將機密資訊藏入於高畫質數位視訊檔案之影像及音訊串流中，以達成機密通訊之目的。本論文大致分成兩部分，第一部分為對H.264/AVC之視訊資訊隱藏。本研究提供了多種嵌入方法以因應不同的應用及影片。論文的第二部分為對MPEG AAC之音訊資訊隱藏機制。結合視訊及音訊的嵌入機制，達成高容量資訊隱藏，且盡量保持音視訊品質之目的。此外，為了提升資訊嵌入的效率，我們亦提出了一個模式複製的程序，以增進資料嵌入之執行速度。實驗結果顯示本論文所提出的演算法能夠藏入大於10%視訊檔案大小之機密資訊容量，並且對於音視訊品質及影片的壓縮率皆列入考量。In this research, we consider to exploit the large volume of audio/vidio data streams in compressed video clips/files for effective steganography. By observing that most of the widely distributed video files employ H.264/AVC and MPEG AAC for video/audio compression, we examine the coding features in these data streams and determine good choices of data modifications for reliable and acceptable information hiding, in which the perceptual quality, compressed bit-stream length, payload of embedding, effectiveness of extraction and efficiency of execution are taken into account. Different settings can thus be used to cope with varying requirements of applications. Experimental results demonstrate that the payload of the selected features for achieving a good balance among several constraints can be over $10\%$ of the compressed video file size.
