To use this decoder, you need to use FengYun-2 satellite transport frames. This is very easy to get with the GNU-Radio schema from this repository. After receiving the transport frames, they need to be synchronized and de-randomized.

Use:

Deframer.exe(.py) data_from_GR.bin fengyun_svissr.svissr 

To use the decoder, use the command:

python3 decoder.py -i fengyun_svissr.svissr

...or if you're using Windows:

FengYun-2_S-VISSR_Decoder.exe -i fengyun_svissr.svissr

You will get decoded images in decoder folder.