High speed, low complexity, and interoperability are just three of the main advantages turning the MPEG stream
watermarking into a hot research topic. Unfortunately, viable solutions (in terms of robustness, data payload and
transparency) are yet to be found. In their previous work, the authors computed general models for the watermarking
attack effects (StirMark, linear & nonlinear filtering, rotations) in the MPEG-4 AVC stream. These models (expressed as
noise matrices) are now the starting point for evaluating three classes of watermarking insertion techniques (substitutive,
additive, and multiplicative). For each class, a specific set of noise matrices is first computed by particularising the
general model. Secondly, the corresponding capacity values (i.e. the largest data payload which can be inserted for
prescribed transparency and robustness) are computed. The paper is concluded with a comparison among these method
performances. The experiments are run on a video corpus of 10 video sequences of about 25 minutes each.
Nowadays, robust watermarking clearly identified its functionality within the multimedia production chain, from the content creation to the end-user consumption: property right identification and copy-maker tracking. In the quest for the speed required by today's real-time applications, compressed-domain watermarking becomes a hot research topic. This study evaluates the watermarking capacity in the MPEG-4 AVC domain in order to establish whether and to what extent compressed domain watermarking is viable. In this respect, the additive watermarking techniques are modelled by discrete noisy channels with non-causal side information at the transmitter. The study considers several attacks (linear and non-linear filtering, geometric) and computes the capacity of the corresponding channels. The experimental results are obtained out of processing a natural video corpus of 10 video sequences belonging to different movies, each of them about 25 minutes long (35000 frames in each video sequence).
The ever-increasing Internet distribution of video content is echoed in ever-increasing efforts to devise systems balancing
copyright protection and user rights. Watermarking is such an example: by persistently and imperceptibly associating some
data with the host video, it offers at the same time a reliable and user-friendly solution for copyright infringement tracking.
This paper takes a closer look at the apparent contradiction between watermarking (using the visual redundancy of the video
to embed the data) and compression (eliminating the visual redundancy in order to speed up distribution and to alleviate
storage requirements). In this respect, the viability of compressed domain watermarking is evaluated by analysing the visual
effects of the MPEG-4 AVC stream alteration. The corpus consists of 10 video sequences of about 25 minutes each, coded at
256kbps and 64 kbps.
The explosion of VoD and HDTV services opened a new direction in watermarking applications: compressed domain
watermarking, promising at least tenfold speed increase. While sound technical approaches to this emerging field are
already available in the literature, at our best knowledge the present paper is the first related theoretical study. It
considers the ISO/IEC 14496-10:2005 standard (also known as MPEG-4 AVC) and objectively describes with
information theory concepts (noisy channel, noise matrices) the effects of the real-life watermarking attacks (like
rotations, linear and non-linear filtering, StirMark). All the results are obtained on a heterogeneous corpus of 7 video
sequences summing up to about 3 hours.
When considering the multimedia production chain from the content creation to the end-user consumption,
watermarking provides a well defined functionality: property right identification and copy-maker tracking. However, its
place within this chain is not yet clearly stated. The present paper describes an objective study aiming at establishing the
functional peculiarities in the cases when watermarking follows compression. First, some general limits concerning the
transparency, robustness and capacity in compressed (MPEG-4 AVC) domain watermarking are identified. Then, these
results are discussed and compared to the uncompressed domain watermarking case. The experiments were carried out
on a video corpus of 5 video sequences, each of them of 35000 frames (about 25 minutes each), coded at 256kbit/s.
Nowadays, a large variety of emerging applications (clickable, video, interactive high definition television, intelligent interfaces) do not only process the multimedia content (audio, video, 3D,...) but some additional data directly connected to it, as well. This enrichment information is usuall transmitted and stored as an additional independent stream (metadata). Such an approach can be restrictive sometimes, mainly for the networks/application with strict bandwidth and/or protocol constraints. An alternative solution is advanced and discussed in this paper. The principle consists in transmitting the metadata via in-band channels obtained by means of data hiding (watermarking) techniques. The challenge is to design data hiding techniques reaching the trade off among transparency (the enrichment process should not alter the perceptual quality of the host media), robustness (possibility to recover the metadata at the end user even when the high distortions occur through the channel) and data payload (the amount of metadata which can be inserted). The paper investigates the feasibility of such techniques by evaluating the maximal data payload (the watermarking capacity) under given robustness and transparency constraints. The results are compared to the resources needed by some existing enrichment applications. The experiments are carried out in collaboration with the French mobile service operator SFR (Vodafone Group) and consider video sequences watermarked in the DWT domain.
Audio watermarking aims at ensuring the property rights for digital audio (music, speech). In this respest, some extra information, referred to as mark or watermark, is embedded into original (unmarked) clip. By detecting this information, the true owner should be identified and the copy maker should be tracked down. This paper starts by identifying the audio peculiarities under the watermarking framework. Then, the first method hybridising spread spectrum and side information principles for audio watermarking is advanced. This method meets the nowadays challenging reqirements of transparency, robustness, and data payload. The experiments were performed in collaboration with the French SFR (Vodafone Group) mobile service provider.
Watermarking aims at enforcing property right for digital video: a mark is imperceptibly - transparently - embedded into original data. The true owner is identified by detecting this mark. The robust watermarking techniques allow the mark detection even when the protected video is attacked. Transparency and robustness constraints restrict the mark size: the better transparency and robustness, the smaller the data payload. The paper presents a method to evaluate the maximum quantity of information which can be theoretically inserted into the 2D-DCT coefficient hierarchy, for prescribed transparency and robustness. This approach relies on the noisy channel model for watermarking. Within this mathematical framework, the maximal data payload is expressed by the channel capacity. As any capacity evaluation procedure requires an intimate knowledge of the noise sources, the paper first describes the developed statistical approach enabling: (1) to properly handle the inner dependency existing among successive frames in a video sequence, and (2) to accurately check out the Gaussian behaviour for each noise source. The experiments were carried out in partnership with the SFR mobile service provider in France (Vodafone group).
With the advent of the Information Society, video, audio, speech, and 3D media represent the source of huge economic benefits. Consequently, there is a continuously increasing demand for protecting their related intellectual property rights. The solution can be provided by robust watermarking, a research field which exploded in the last 7 years. However, the largest part of the scientific effort was devoted to video and audio protection, the 3D objects being quite neglected. In the absence of any standardisation attempt, the paper starts by summarising the approaches developed in this respect and by further identifying the main challenges to be addressed in the next years. Then, it describes an original oblivious watermarking method devoted to the protection of the 3D objects represented by NURBS (Non uniform Rational B Spline) surfaces. Applied to both free form objects and CAD models, the method exhibited very good transparency (no visible differences between the marked and the unmarked model) and robustness (with respect to both traditional attacks and to NURBS processing).
The cell phone expansion provides an additional direction for digital video content distribution: music clips, news, sport events are more and more transmitted toward mobile users. Consequently, from the watermarking point of view, a new challenge should be taken: very low bitrate contents (e.g. as low as 64 kbit/s) are now to be protected. Within this framework, the paper approaches for the first time the mathematical models for two random processes, namely the original video to be protected and a very harmful attack any watermarking method should face the StirMark attack. By applying an advanced statistical investigation (combining the Chi square, Ro, Fisher and Student tests) in the discrete wavelet domain, it is established that the popular Gaussian assumption can be very restrictively used when describing the former process and has nothing to do with the latter. As these results can a priori determine the performances of several watermarking methods, both of spread spectrum and informed embedding types, they should be considered in the design stage.
Nowadays, alongside with the traditional voice signal, music, video, and 3D characters tend to become common data to be run, stored and/or processed on mobile phones. Hence, to protect their related intellectual property rights also becomes a crucial issue. The video sequences involved in such applications are generally coded at very low bit rates. The present paper starts by presenting an accurate statistical investigation on such a video as well as on a very dangerous attack (the StirMark attack). The obtained results are turned into practice when adapting a spread spectrum watermarking method to such applications. The informed watermarking approach was also considered: an outstanding method belonging to this paradigm has been adapted and re evaluated under the low rate video constraint. The experimental results were conducted in collaboration with the SFR mobile services provider in France. They also allow a comparison between the spread spectrum and informed embedding techniques.