Frank Hartung

Watermarking of uncompressed and compressed video

Abstract In this paper, methods for embedding additive digital watermarks into uncompressed and compressed video sequences are presented. The basic principle borrows from spread spectrum communications. It consists of addition of an encrypted, pseudo-noise signal to the video that is invisible, statistically unobtrusive, and robust against manipulations. For practical applications, watermarking schemes operating on compressed video are desirable. A method for watermarking of MPEG-2 encoded video is presented. The scheme is a compatible extension of the scheme operating on uncompressed video. The watermark is generated exactly in the same manner as for uncompressed video, transformed using the discrete cosine transform (DCT) and embedded into the MPEG-2 bit-stream without increasing the bit-rate. The watermark can be retrieved from the decoded video and without knowledge of the original, unwatermarked video. Although an existing MPEG-2 bit-stream is partly altered, the scheme avoids visible artifacts by addition of a drift compensation signal. The proposed method is robust and of much lower complexity than a complete decoding process followed by watermarking in the pixel domain and re-encoding. Fast implementations exist which have a complexity comparable to a video decoder. Experimental results are given. The scheme is also applicable to other hybrid transform coding schemes like MPEG-1, MPEG-4, H.261, and H.263.

Spread spectrum watermarking: malicious attacks and counterattacks

Most watermarking methods for images and video have been proposed are based on ideas from spread spectrum radio communications, namely additive embedding of a (signal adaptive or non-adaptive) pseudo-noise watermark pattern, and watermark recovery by correlation. Even methods that are not presented as spread spectrum methods often build on these principles. Recently, some skepticism about the robustness of spread spectrum watermarks has arisen, specifically with the general availability of watermark attack software which claim to render most watermarks undetectable. In fact, spread spectrum watermarks and watermark detectors in their simplest form are vulnerable to a variety of attacks. However, with appropriate modifications to the embedding and extraction methods, spread spectrum methods can be made much more resistant against such attacks. In this paper, we review proposed attacks on spread spectrum watermarks are systematically. Further, modifications for watermark embedding and extraction are presented to avoid and counterattack these attacks. Important ingredients are, for example, to adapt the power spectrum of the watermark to the host signal power spectrum, and to employ an intelligent watermark detector with a block-wise multi-dimensional sliding correlator, which can recover the watermark even in the presence of geometric attacks.

Digital watermarking of MPEG-2 coded video in the bitstream domain

Embedding information into multimedia data, also called watermarking, is a topic that has gained increased attention. For video broadcast applications, watermarking schemes operating on compressed video are desirable. We present a scheme for robust watermarking of MPEG-2 encoded video. The watermark is embedded into the MPEG-2 bitstream without increasing the bit-rate, and can be retrieved even from the decoded video and without knowledge of the original, unwatermarked video. The scheme is robust and of much lower complexity than a complete decoding process followed by watermarking in the pixel domain and re-encoding. Although an existing MPEG-2 bitstream is partly altered, the scheme avoids visible artifacts by adding a drift compensation signal. The scheme has been implemented and the results confirm that a robust watermark can be embedded into MPEG encoded video which can be used to securely transmit arbitrary binary information at a data rate of several bytes/second. The scheme is also applicable to other hybrid coding schemes like MPEG-1, H.261, and H.263.

Fast public-key watermarking of compressed video

Most watermarking techniques for images and video techniques involve a private key, for example a pseudo-noise signal, which is required for retrieval of the watermark information. This key is typically not public, because publication of the key would give rise to attacks on the watermark. In practical systems, however, watermarking techniques are required that enable public decoding of the watermark. In this paper, an extension of spread-spectrum watermarking is presented which enables public decoding and verification of the watermark, without at the same time giving the possibility of removing the watermark. The underlying idea, is to make only parts of the pseudo-noise key public. The scheme can be combined with a fast compressed-domain embedding technique to facilitate on-the-fly compressed-domain public-key watermarking.

Digital watermarking of MPEG-4 facial animation parameters

Abstract The enforcement of intellectual property rights is difficult for digital data. One possibility of supporting enforcement is the embedding of digital watermarks containing information about copyright owner and/or receiver of the data. Watermarking methods have already been presented for audio, images, video, and polygonal 3D models. In this paper, we present a method for digital watermarking of MPEG-4 facial animation parameter data sets. The watermarks are additively embedded into the parameter values and can be retrieved either from the watermarked parameters or from video sequences rendered using the watermarked animation parameters for head animation. For retrieval from rendered sequences, the facial animation parameters have to be estimated first. We use a model-based approach for the estimation of the facial parameters that combines a motion model of an explicit 3D textured wireframe with the optical flow constraint from the video data. This leads to a linear algorithm that is robustly solved in a hierarchical framework with low computational complexity. Experimental results confirm the applicability of the presented watermarking technique.

Streaming technology in 3G mobile communication systems

Third-generation (3G) mobile communication systems combine standardized streaming with a range of unique services to provide high-quality Internet content that meets the specific needs of the rapidly growing mobile market.

Digital watermarking of text, image, and video documents

Abstract The ease of reproduction, distribution, and manipulation of digital documents creates problems for authorized parties that wish to prevent illegal use of such documents. To this end, digital watermarking has been proposed as a last line of defense. A digital watermark is an imperceptible, robust, secure message embedded directly into a document. The watermark is imperceptible both perceptually and statistically. Robustness means that the watermark cannot be removed or modified unless the document is altered to the point of no value. The watermark is secure if unauthorized parties cannot erase or modify it. Current watermarking schemes may be viewed as spread-spectrum communications systems, which transmit a message redundantly using a low-amplitude, pseudo-noise carrier signal. An example highlights the basic mechanisms and properties of spread spectrum and their relation to watermarking. Finally, specific issues in watermarking of text, images, and video are discussed, along with watermarking examples.

Copyright Protection in Video Delivery Networks by Watermarking of Precompressed Video

Digital video data can be copied repeatedly without loss of quality. Therefore, copyright protection of video data is a more important issue in digital video delivery networks than it was with analog TV broadcast. One method of copyright protection is the addition of a “watermark∝ to the video signal which carries information about sender and receiver of the delivered video. Therefore, watermarking enables identification and tracing of different copies of video data. Applications are video distribution over the World Wide Web (WWW), pay-per-view video broadcast, or labeling of video discs and video tapes. In the mentioned applications, the video data is usually stored in compressed format. Thus, the watermark must be embedded in the compressed domain. We present a scheme for robust watermarking of MPEG-2 encoded video. The scheme is of much lower complexity than a complete decoding process followed by watermarking in the pixel domain and re-encoding. Although an existing MPEG-2 bitstream is partly altered, the scheme avoids drift by adding a drift compensation signal. The scheme has been implemented and the results confirm that a robust watermark can be embedded into MPEG encoded video which can be used to securely transmit arbitrary binary information at a data rate of several bytes/second. The scheme is easily applicable to other video coding schemes like MPEG-1, H.261, and H.263.

Proxy-based TCP-friendly streaming over mobile networks

Mobile media streaming is envisioned to become an important service over packet-switched 2.5G and 3G wireless networks. At the same time, TCP-friendly rate-adaptation behavior for streaming will become an important IETF requirement. In this paper we investigate TCP-friendly on-demand streaming over wired and wireless links. We consider two approaches for achieving TCP-friendliness: first, by tunneling RTP packets over TCP and secondly by employing an RTP server rate control which does not exceed a variable rate constraint derived from the recently developed TFRC protocol. To allow a reasonable fair comparison between TCP and TFRC, we assume a simple retransmission mechanism on top of TFRC. We consider streaming from a server in the public Internet to both wired and wireless clients. For the wireless case we assumed a client which is connected to the public Internet via a dedicated 64 kbps WCDMA streaming bearer. Simulation results carried out in ns-2 show that TCP and TFRC can not fully utilize the WCDMA bearer at 5% packet loss rate over the shared public Internet link. Smooth playout of a typical 64 kbps video stream would require high initial buffering delays (>10 seconds) and large receiver buffer sizes (>60 KB). We finally investigate the gains from a proxy that splits the connection and uses TCP-friendly congestion control only over the shared part of the client-server connection. Simulation results show improvements in average throughput and wireless link utilization. By employing appropriate packet re-scheduling mechanisms, the initial buffering delay and the client buffer size for a typical 64 kbps video stream can be decreased by a factor of three to four.

Advances in network-supported media delivery in next-generation mobile systems

This article presents new concepts for network-supported media delivery in mobile networks. Automatic composition and merging of networks are central parts of these concepts. Media delivery is no longer an end-to-end service that only uses the network as an IP transport. Instead, these concepts create a service-aware network and provide customized delivery support through per-service overlay networks. They also integrate specialized processing nodes as part of the delivery topology, which include transcoders but also more complex processors, such as localized program insertions or personalized spam control. This article describes the underlying concepts and how these new network capabilities for media delivery services are requested, invoked, and managed