{"id":194,"date":"2006-01-25T19:56:55","date_gmt":"2006-01-26T03:56:55","guid":{"rendered":"http:\/\/multimedia.cx\/eggs\/?p=194"},"modified":"2006-10-04T21:33:11","modified_gmt":"2006-10-05T04:33:11","slug":"nes-compression","status":"publish","type":"post","link":"https:\/\/multimedia.cx\/eggs\/nes-compression\/","title":{"rendered":"NES Compression"},"content":{"rendered":"

For budding computer geeks like myself, volume 20\/January 1991 issue of Nintendo Power magazine<\/a> (Mega Man III<\/em><\/a> cover) was of particular interest. In this issue, the editors attempted to shed some light on the technical matters driving the 8-bit Nintendo Entertainment System and give insufferable know-it-alls further opportunity to truly know it all.<\/p>\n


\n\"8-bit
\n<\/center><\/p>\n

I still recall the puerile, simplistic explanation for compression using a metaphor every Nintendo nerd could relate to: Tetris! I still think about this article sometimes and wonder what compression method they used and for which games. In fact, I located the relevant article section and scanned it for your enjoyment\/edification:<\/p>\n


\n\"NES
\nClick for larger image<\/em><\/a>
\n<\/center><\/p>\n

I came across this document<\/a> describing a compression algorithm used for a Zelda<\/a><\/em> game on the Super NES, the direct successor to the NES, both market-wise and on a technical level. It seems that the scheme is largely a flexible RLE scheme<\/a> which allows for decoding single- or double-byte runs (output 5 instances of byte 0x56 vs. output 5 instances of 0x56 0x42); decoding runs of an incrementing byte (e.g., output a sequence of 4 incrementing bytes starting with 0xA2: 0xA2 0xA3 0xA4 0xA5); and even using into the encoded buffer as a dictionary and copying runs from a specified index.<\/p>\n","protected":false},"excerpt":{"rendered":"

How do you compress data on an 8-bit NES?<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30,4],"tags":[],"class_list":["post-194","post","type-post","status-publish","format-standard","hentry","category-nintendo","category-reverse-engineering"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t