MASTER THESIS Video Watermarking - Computer Graphics Group ...

5.3 Time Consumption
This section discusses time consumption of both the embedding and the
detection pipelines. The time has been measured by standard Unix utility called
time; the user-space time has been considered only. Average results of three
iterations in Table 3 show that all the methods are basically equivalent in
embedding but noise method is the worst in detection because of visual data
decoding.
The test has been executed on a machine with the following configuration:
Intel Pentium M (Centrino) processor, 1.60GHz, 3200 bogomips
512MB DDR PC2700 memory, 333MHz
openSUSE 10.1 operating system
Table 3: Time consumption test results
The test has proved that the plugin is applicable in practice.
5.4 Robustness
Robustness test scripts simulate real attacks applied either intentionally or
unintentionally to watermarked video sequences. In the simulations, they have
been executed on pre-filtered watermarked sequences – the sequences have been
remuxed in order to contain (besides parameter sets) intra coded slices only
because the watermark is embedded into intra coded slices only.
Most of the tests proceeds as follows.
A watermarked pre-filtered sequence is converted using MPlayer to the raw
video stream of single images, one image per frame. During the conversion, the
video signal processing filter is applied eventually.
Then, the raw stream is compressed by x264 encoder producing H.264 video
stream at the former bit-rate with intra coded slices only, and muxed to the
Matroska container format.
The recompression at the former bit-rate obviously impairs the embedded
watermark but the attacks are simulated more faithfully. The impairment rate of
recompression is measured in Section 5.4.1.
Finally, the detection process takes place in such an attacked sequence. The
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