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+# Compress games
+
+
+## Compression function
+
+The function is called `/RetroDECK/functions/compression.sh`
+
+
+## Compression targets reference list
+
+The reference list is located under:
+
+`/RetroDECK/emu-configs/defaults/retrodeck/reference_lists/compression_targets.cfg`
+
+The config is populated with compression formats with within [] and what es-de folders that are targeted for the format compression.
+Each system can only have one format.
+
+Each new system has to be on a new line under it's compression format
+
+### Example
+
+[chd]
+3do
+amigacd32
+[rvz]
+gc
+[zip]
+atari2600
+
+- 3do and amigcd32 is converted to chd
+- gc is conrverted to rvz
+- atari2600 is converted to zip
+
+## How to add new system to compress
+
+1. Make sure the emulator supports the compression format and RetroDECK is using that version that supports it.
+2. Add the es-de folder name to `compression_targets.cfg` to the compression format it supports.