The challenge material

For each watermarking technology, the challenge included three songs, encoded using the wav format. These songs were two minute long, and were sampled at the sampling rate of $Fs=44100Hz$.

• The first song was an original, never released song. We will denote it by $A$.
• The second song was the marked version of the first one. We will denote it by $AM$.
• The last song was a marked, never released song. We will denote it by $BM$.

The aim of the challenge was to produce a new song $C$, that should

1. be of a sufficient quality (i.e. better than or equivalent to an MP3 encoding at 64 kbit/s.)
2. fail the detection test (i.e. the detector corresponding to the marking algorithm should not be able to detect the mark.)

Obviously, recovering the original clean song corresponding to $BM$ solves the problem, but as we have seen previously, doing this is much more than is actually required to win the challenge.