NSFDRV

NSFDRV is to Include the information of sound driver to NSF.

Background

• NSF-Player can detect sound driver, and NSF-Player can fix the bug of old sound driver for chiptune such as mck.

In N163 audio, length of waveform is not set correctly.
Sample length register ($7C) upper 2bit is not correctly.
Reference: https://wiki.nesdev.org/w/index.php/Namco_163_audio#Sound_RAM_.247C_-_High_Frequency_and_Wave_Length

FDC audio is not enable.
$4023 is not set.
Reference: https://wiki.nesdev.org/w/index.php/FDS_audio#Master_I.2FO_enable_.28.244023.29

• User can assert that user's NSF is original easily. (NSF is not ripped data from rom.)
• If occur BUG in sound driver, Developer can get information of version number from NSF file for the debug.

File Format

There is 8 bytes information of sound driver after NSF header. This 8 bytes information is on actual rom image of 6502.

offset          Bytes   Function
-------------------------------------------------
$0000 - $007F   128     NSF Header
$0080 - $0085   6       Name of sound driver
$0086           1       Version integral number
$0087           1       Version integral number

List of sound driver

• OFGS (http://offgao.no-ip.org/ofgs/)

ASCII  :      "OFGS  "
Binary :      $4F $46 $47 $53 $20 $20

• FamiTracker NSF Driver (http://www.famitracker.com)

ASCII  :      "FTDRV "
Binary :      $46 $54 $44 $52 $56 $20

• NES Sound Driver & Library (https://github.com/Shaw02/nsdlib)

ASCII  :      "NSDL  "
Binary :      $4E $53 $44 $4C $20 $20

• Development code (for no-bug sound driver)

ASCII  :      "      "
Binary :      $20 $20 $20 $20 $20 $20

Old chiptune sound driver have some bugs. Some NSF Player adjust this bug of old chiptune sound driver. But, It adjuster affect the new sound driver without bug. Therefore, this information is need now.

NSF Player detect the sound driver name. If sound driver have not bug, then adjuster is disable. If sound driver is unknown (old sound driver), then adjuster is enable.

Players

The following implementations of NSFDRV exist:

• TNS-HFC4
• hoot