As of late 2024 and into 2025, Mojang is moving toward the "Cubic Chunks" format (height up to 4064 blocks). This means the MCA format will eventually become obsolete. However, the principles of the (reading old chunk data, translating block IDs, and recompressing) will remain the same for legacy preservation.
During conversion, the tool will:
Depending on your technical comfort level, you can convert these files using simple renaming or dedicated software tools. 1. The Manual Renaming Method mcr to mcd converter
This is the standard raw memory card format. It is natively used by popular emulators like ePSXe , RetroArch (Beetle PSX/PCSX Rearmed cores), and FPse . As of late 2024 and into 2025, Mojang
# Payload payload = mcr_data[chunk_start+5 : chunk_start+5+length-1] # -1 accounts for the type byte in length count? # Actually, length includes the type byte. So payload length is length - 1. # But standard logic is usually just strict slicing. # Let's just grab exact bytes. payload = mcr_data[chunk_start+5 : chunk_start+length+4] # +4 because length is payload+type During conversion, the tool will: Depending on your
You can change these formats using specialized desktop utilities or simple manual file modification. 1. MemcardRex (Recommended)