Academic & Scientific Articles

Permanent URI for this communityhttp://dl.cerist.dz/handle/CERIST/3

Browse

Subject: search.filters.subject.H264/AVC standard

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Watermarking of compressed video based on DCT coefficients and watermark preprocessing
    (CERIST, 2010-12) Bouchama, Samira; Hamami, Latifa; Aliane, Hassina
    Considering the importance of watermarking of compressed video, several watermarking methods have been proposed for authentication, copyrights protection or simply for a secure data carrying through the Internet. Applied to the H.264/AVC video standard, in most of cases, these methods are based on the use of the quantized DCT coefficients often experimentally or randomly selected. In this paper, we introduce a watermarking method based on the DCT coefficients using two steps: the first one consists in a watermark pre-processing based on similarity measurement which can allow to adapt the best the watermark to the carrying coefficients of low frequencies. A second step takes advantage from the coefficients of high frequencies in order to maintain the video quality and reduce the bitrate. Results show that it is possible to achieve a very good compromise between video quality, embedding capacity and bitrate.
  • Thumbnail Image
    Item
    Watermarking of H.264 Coded Video Based on the Shifted-Histogram Technique
    (2010-12) Bouchama, Samira; Hamami, Latifa; Qadri, Muhammad Tahir; Ghanbari, Mohammed
    Reversible video watermarking through shifted histogram of the quantized coefficients of the H.264/AVC coded video is introduced. In CIF sequences, the embedded data of a capacity of more than 2500 bits in I frame is possible and can exceed 7000 bits if we also exploit about 10 P frames in the GOP for the embedding. While the degradation introduced by the watermarked can achieve around 13 dB, the subjective impacts are almost negligible. This data hiding is reversible and it increases the encoded bits by less than 1 % and less than the embedding capacity offering the opportunity to carry information at a lower bitrate rather than a second channel.