NSF (file format)
| Filename extension | .nsf |
|---|---|
| Developed by | Kevin Horton |
| Type of format | Music file |
The NES Sound Format (NSF) is the filename extension of the audio file format originally designated as NESM (Nintendo Entertainment System Music) by the author Kevin Horton. This format was originally designed for playback in a custom hardware device named HardNES by Horton. Over the years, the NSF format has been implemented for playback on many platforms via plugins, stand-alone players, emulators and also the NES PowerPak.
The particulars of the NSF format resemble the SID format loosely, where a header is prepended and then the original audio data follows. The original audio data commonly has been extracted from a ROM image or disk image and then modified for stand-alone playback by various players. The original audio data is also commonly referred to as an audio driver or music engine. The audio driver is then completely isolated from the rest of the code, data and graphics that have nothing to do with the audio driver. A complete NSF is considered a multiple song and sound effect container for one particular game or composition.
Platforms and chips[edit]
The following 6502 platforms with a RP2A03/RP2A07 microprocessor including some clone units are compatible with the NSF format and current NSF players. These platforms can be PAL or NTSC or dual PAL/NTSC from any region. There are exceptions to the rule where if any part of a platform that has another microprocessor such as the Zilog Z80 will not be supported.
- Nintendo Entertainment System
- Famicom
- Family Computer Disk System
- Nintendo Vs. (Dual) System
- PlayChoice-10
- Dendy (console)
- Various NES and Famicom clone units.
The following chips and components are supported in the NSF specification.
- RP2A03 APU NTSC
- RP2A07 APU PAL
- RP2C33 Audio Channel (FDS)
- Konami VRC6 Audio
- Konami VRC7 Audio
- Namco N163 Audio
- Nintendo MMC5 Audio
- Sunsoft 5B Audio (variant of YM2149F/AY-3-8910)
NSF format supports all five normal audio channels of the APU as well as the other audio expansion chips previously listed.
- Square 1
- Square 2
- Triangle
- Noise
- DMC - Including 1-bit delta encoded samples or using the 7-bit counter for PCM playback.
Header[edit]
The NSF header is prepended to the original audio data and code.[citation needed] The header was designed to be as flexible as possible and to allow for hardware and emulation playback. The header supports three specific addresses; the first one is the beginning address of the audio data, the next two are entry points to the play and initialization code respectively.[citation needed]
The header supports PAL, NTSC, dual PAL/NTSC and also allows to adjust the playback speed.[citation needed] This playback speed is not meant to be used to adjust the speed of songs in a rip, but to account for various units with a microprocessor speed that is not considered standard, such as many clone NES units from China.[citation needed]
The header also has an extra sound chip support setting for six expansion chips. No commercial game ever used more than one expansion sound chip.[citation needed] However, many fan compositions do use up to all expansion sounds chips in the NSF format. There are also three slots for name of song, artist and copyright holder. Each one of these has a limit of 32 ASCII characters.[citation needed]
NSF hardware players[edit]
HardNES is the first NSF hardware player invented by Kevin Horton that is run by a NES CPU and a FPGA. It features a LED, stereo sound and 128 KB RAM chip which contains all the RAM used by the control system and the emulated ROM space that is bank-switched.[citation needed]
CopyNES NSF Cart is another creation by Horton. The NSF Cart is used in combination with a CopyNES. The NSF file is transferred to the CopyNES and then to the NSF Cart for NSF playback. The maximum sized NSF for the original cart is 128 KB.[citation needed]
NES PowerPak is an NES cartridge that has a CompactFlash card port that enables the transfer of ROM images to this cart. The 512 KB RAM chip and the FPGA circuits allow this cartridge to be flexible enough to support many iNES mappers including the NSF specification.[citation needed]
References[edit]
This article "NSF (file format)" is from Wikipedia. The list of its authors can be seen in its historical. Articles copied from Draft Namespace on Wikipedia could be seen on the Draft Namespace of Wikipedia and not main one.
