To understand the conversion process, one must first understand the two file types involved. An .nds file is a raw ROM image containing the exact read-only memory data extracted from a physical Nintendo DS game cartridge. It contains the game’s code, graphics, audio, and file system. On the other hand, a .7z file is not a media or game format at all. It is a compressed archive created by the open-source program 7-Zip. It uses the LZMA and LZMA2 algorithms to drastically reduce the file size of whatever data is placed inside it. Therefore, converting 7z to NDS is not a file conversion in the traditional sense, such as changing a PNG image to a JPEG. Instead, it is an extraction process. The NDS file already exists inside the 7z container; the software simply needs to unpack it.
You have just performed the exact operation a mythical "converter" would do. 7z to nds converter
is the actual game ROM (the clothes inside the suitcase). To understand the conversion process, one must first