so... i tried downloading zelda, ocarina of time here in romU... the downloaded file was only about 50+ MB... but after extracting... it came about 2.5GB!!! my question is... how in the world did you do it??? i have 7z and winrar but when i tried compressing 113MB worth of files... it came up with only 110MB... i only saved 3MB anyone shed a light?
It depends on the files. Many files, like JPEG, MPEG, etc, are already very optimized for space. The encoding on the pictures and movies already removes much of the redundant data. But ROMs are loaded with redundant data and blank spaces, so these can be compressed much, much lower.
MP3 are already compressed. In the zelda archive, there are a number of almost identical roms (different dumps, hacks etc). This means a lot of repeated data, which improves the compression ratio significantly.
