Research Reports

Permanent URI for this collectionhttp://dl.cerist.dz/handle/CERIST/34

Browse

Filters

2012 - 20132

Settings

Subject: search.filters.subject.Drift distortion

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    H.264/AVC Data Hiding Algorithm with a Limitation of the Drift Distortion
    (CERIST, 2012) Bouchama, Samira; Hamami, Latifa; Aliane, Hassina
    Many data hiding algorithms have been proposed for the latest video codec H.264/AVC, most of them are based on the 4x4 luma DCT coefficients. However, the drift distortion is the main reason which limits the embedding capacity in data hiding algorithms based on DCT coefficients. Few methods have been proposed to compensate or eliminate the error propagation. Though, they are either non-blind, only detectable or need prior knowledge of the encoded blocks and thus cannot be used for real time broadcasting. In this paper we show that it is possible to reduce considerably the error propagation for real time applications. The proposed algorithm exploits the method of watermarking paired-coefficients in each block in order to bring the error to the middle of the block matrix. We evaluate the distortion caused by each paired-coefficients in order to give a watermarking priority to the pairs which introduce the minimum error. The proposed scheme offers a very good compromise between the video distortion, the increase in bitrate and the embedding capacity.
  • Thumbnail Image
    Item
    Error Drift Compensation for Data Hiding of the H.264/AVC
    (CERIST, 2013) Bouchama, Samira; Hamami, Latifa; Aliane, Hassina
    The error propagation problem is one of the most attractive issues in the field of data hiding of compressed video because the achievement of several data hiding characteristics remains dependant on it. In this paper, a solution to compensate the error propagation is proposed for data hiding of the H.264/AVC. The error compensation is performed by a prior measurement of the introduced error in the watermarked block or in the neighbouring blocks. Two schemes are proposed: The first algorithm exploits the method of watermarking paired-coefficients in each block in order to bring the error to the middle of the block matrix. The distortion caused by each paired-coefficient is calculated in order to give a watermarking priority to the pairs which introduce the minimum error. In the second scheme, the error estimated in the neighbouring blocks is reduced from the residuals during the encoding process. In both schemes, results show that an important improvement of the video quality can be achieved and a good compromise is provided between the video distortion, the bitrate and the embedding.