MASTER THESIS Video Watermarking - Computer Graphics Group ...

loud speakers.
The watermark plugin stands for an element in a suchlike pipeline. The
plugin can be divided into two parts: the GStreamer part and the main part, and
works in either embedding (see Section 4.2.2) or detection (see Section 4.2.3)
mode.
The GStreamer part implements the GStreamer interface which is
thoroughly documented on the project's website [12], thus the source code is only
briefly commented.
This part parses incoming data blocks of H.264 stream into NAL units
which are further decoded using the codec, mentioned in Section 4.1. As soon as a
slice is decoded, it is forwarded to the main part of the plugin. Then, in
embedding mode, the watermarked slice is encoded again and sent to the output,
or in detection mode, detection statistics are given.
The main part does watermark embedding or detection, depending on the
mode.
The plugin is written as a library in programming language C and the
source code counts about 3 500 lines. The usage of the plugin is described in
Appendix B and the documentation is provided in Appendix C.
4.2.2 Embedding
In the embedding mode, the plugin accepts a H.264 stream as the input,
invokes the embedding process and outputs the same but possibly watermarked
H.264 stream. The embedding pipeline is illustrated in Figure 9.
Figure 9: Watermark pipeline in embedding mode
Non-watermarked slices and other NAL units are passed through without
any changes.
In the current implementation of the plugin, only intra coded slices are
watermarked. This is because inter prediction is quite complicated and is not
necessary for objectiveness of the thesis results.
Inputs to the embedding process are:
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