required output dimensions.

**GS:** For the GS encoding, we took the sub-series of size $512$ and turned them into $K=64$ series of size $K=64$, using a stride of $s=7$. This leads to $505$ values per sub-series in total. The remaining 7 points are discarded (3 at the beginning, 4 at the end). In addition to the original formulation, we explored three further variants: 1) $P=255$, 2) $P=1$, and 3)the min-max scaling only, that is $P=1$ without rounding to the nearest integer. Since it turned out that the first and last variant were giving extremely similar results, for clarity purposes, only $P=1$ and the min-max variants are presented in the results. For all the three variants, we set the upper and lower bounds $\mathrm{UB}$ and $\mathrm{LB}$ to $1.2$ the maximum and the minimum observed over the training set, similarly to GAF.

**SP:** For the Spectrogram, we propose to perform the STFT on the entire time series, using a Hanning window of size 126 and a temporal stride to 8. The output is of size $64\times7\,680$ and is split into 120 slices of size $64\times64$. This approach is similar to that of splitting first the series before performing the STFT but limits 