207 research outputs found
Fast watermarking of MPEG-1/2 streams using compressed-domain perceptual embedding and a generalized correlator detector
A novel technique is proposed for watermarking of MPEG-1 and MPEG-2 compressed video streams. The proposed scheme is applied directly in the domain of MPEG-1 system streams and MPEG-2 program streams (multiplexed streams). Perceptual models are used during the embedding process in order to avoid degradation of the video quality. The watermark is detected without the use of the original video sequence. A modified correlation-based detector is introduced that applies nonlinear preprocessing before correlation. Experimental evaluation demonstrates that the proposed scheme is able to withstand several common attacks. The resulting watermarking system is very fast and therefore suitable for copyright protection of compressed video
DCT-based video downscaling transcoder using split and merge technique
2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Diversity and importance measures for video downscaling
2004-2005 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe
Dyadic spatial resolution reduction transcoding for H.264/AVC
In this paper, we examine spatial resolution downscaling transcoding for H.264/AVC video coding. A number of advanced coding tools limit the applicability of techniques, which were developed for previous video coding standards. We present a spatial resolution reduction transcoding architecture for H.264/AVC, which extends open-loop transcoding with a low-complexity compensation technique in the reduced-resolution domain. The proposed architecture tackles the problems in H.264/AVC and avoids visual artifacts in the transcoded sequence, while keeping complexity significantly lower than more traditional cascaded decoder-encoder architectures. The refinement step of the proposed architecture can be used to further improve rate-distortion performance, at the cost of additional complexity. In this way, a dynamic-complexity transcoder is rendered possible. We present a thorough investigation of the problems related to motion and residual data mapping, leading to a transcoding solution resulting in fully compliant reduced-size H.264/AVC bitstreams
On transcoding a B-frame to a P-frame in the compressed domain
2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
On the architecture of H.264 to H.264 homogeneous transcoding platform
2007-2008 > Academic research: refereed > Invited conference paperVersion of RecordPublishe
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