Nintendo Entertainment System
The Nintendo Entertainment System (often abbreviated as the NES, also known as the Family Computer or the Famicom in Japan) was an 8-bit home console manufactured by Nintendo, launched in 1983 in Japan and 1985 in the US. Perhaps one of the most popular consoles of all time, it brought Japanese companies into the gaming industry alongside with the release of the MSX home computer and singlehandedly revived the American videogame market after its crash in 1983. Outside of these territories and Western Europe, many other countries experienced this era of gaming through Taiwanese and Russian "Famiclones" of the NES hardware such as the Dendy, Pegasus or the Micro Genius.
Tile viewers such as YY-CHR and Tile Molester can be used to rip from the ROM. Most NES games can be tile ripped without issue (apart from assembly due to tile reuse and possible unused poses) aside form games with compressed graphics (such as games converted to cartridges from Famicom Disk System disks). Color palettes must be manually defined or read through a save-state provided by a compatible emulator if tiles are ripped and extracted through this manner.
Nestopia is a common, easy to use emulator with save state and quick screenshot support. By default, the system has a rather faded color palette overall, matching the output of NES and Famicom titles on most modern displays. It can run nearly every NES and Famicom Disk System game with few, if any, real issues, and only lacks support for unlicensed multicarts. Lastly, It can record videos and audio and has net play for online multiplayer. Unlike FCEUX and Mesen, there are no map, sprite, or tile viewers built into the emulator, meaning it must rely on screenshots alone to rip sprites.
The emulator is also available on Mac OSX with many of the same features as its Windows counterpart. It has only one quick save slot for save states compared to the nine/ten of the Windows-based emulators and requires an external module to enable certain features (a trait common among Richard Bannister's other Mac-based emulators). The Mac build also has the Rewind functionality enabled by default, compared to the other emulators where it must be enabled (or in the case of FCEUX, added through a .lua script).
FCEUX is another easy to use emulator with most of the same features as Nestopia, but with the noteworthy addition of frame-advancing using the emulator's pause function and various .lua scripts to assist in playing games. Its default color palette is different than that of Nestopia's and MESEN's, having slightly increased color contrast and providing slightly different shades and hues to several of the colors. Two features in the emulator useful for sprite-ripping include the PPU viewer and the Name Table viewer which display the current tiles loaded into the system's memory for display on the screen and the background without any sprites respectfully. These must be captured using the computer's Printscreen function (and downsized by 50% in the case of the PPU Viewer) as they cannot be saved directly as image files. Like Nestopia, it has video and audio recording and net play for multiplayer.
Mesen is a modern emulator that focuses on accuracy, even options to emulate the faults or the variations of the NES. Even then, it remains an easily-accessible emulator with a large number of extra tools and features. It can emulate most of the library apart from one mapper that was used in six bootleg games including Hummer Team's Somari and Kart Fighter. For sprite ripping, it includes a tile viewer, sprite viewer, palette viewer and a background viewer, and unlike FCEUX's corresponding tools, it can directly copy the output maps/sprites/tiles to the computer's clipboard or save it to a PNG file. In addition, it can record videos and audio, has net play, and can run HD packs for improved visuals.
Mednafen is a universal, multi-console emulator similar to MESS, with the NES as one of the supported consoles. It contains similar tools to dedicated NES emulators including screen capture, sprite/background layer removal, and frame advance.