SPC700 sound format

SPC ( SPC700 sound file also called ) is a file format for video game music. This includes copies of melodies and music data such as those used in the RAM of the SPC700 sound chip, which was used in the game console Super Nintendo Entertainment System ( SNES). Alternatively, the data may also be processed by a console emulator like ZSNES or Snes9x.

Technology

The SPC700 chip (or its emulator ) produces the sound by calling an embedded program, which processes the stored music data and converts it to an output to the chip sequence of DSP instructions. This in turn produces the sound output according to the DSP instructions. The possibilities of SPC700 - DSP ​​instructions allow the music synthesis by samples (similar to music playback by MOD or IT), and an extensive sound that was produced only from 64 KB of data - while saving as uncompressed WAVE file (when using PCM or similar ) large amounts of data, would in certain longer pieces, require up to hundreds of megabytes. The SPC700 chip generates a 16 -bit output signal with 32 kHz, but SPC700 emulators can be configured to output a different sampling rate (from eight to 48 kHz). The positions within a song are given by tics. This makes it possible to repeat certain areas and play in a loop.

Use

SPC plug-ins available for Winamp, foobar2000, Audacious, Rockbox ( for portable MP3 players ) and other well-known players, some of which have already native SPC support. Some SPC player can even get a higher output quality produce than the chip SPC700 yourself by the sound with a higher sampling rate is given ( up to 192 kHz), using more complex sound interpolation methods and a special " High Quality" optimization how she uses for example SNESAmp. There are also programs such as SPC or SPC2MIDI tool, which are able to produce from SPC files MIDI files.

Meanwhile soundtracks are compressed using the RAR algorithm, by means of a progressive compression, which is not available in the ZIP compression. This archive format saves a lot of space, as usually a large number of samples can be reused within the songs, and they must be stored only, instead they always back up again. The archived files get the extension RSN and be unpacked directly when playing from the player.

Disadvantages

A weakness of the SPC format can be observed at the games Tales of Phantasia and Star Ocean. These games use " streaming " sampling and runtime exchanged samples to circumvent the 64 -KB limit of the SPC700 and be able to use additional instruments and voices. Since the SPC dump only the 64K at the time of storage contains, instead of updating on the basis of changes in the game, many of the songs appear in these games " slanted " or sound " scratchy ". It is striking, for example, that the intro of Tales of Phantasia, Yume wa Owaranai, is played in SPC players consistently without voices. Instead, squeaky noises can be heard.

Plug-ins and players

  • Audacious, a media player for Windows / Linux, the SPC files supported.
  • Audio Overload, an executable under Windows / Mac / Linux player designed specifically for video game music, the support among many others, SPC files.
  • Chipamp, a company initiated by OverClocked ReMix Winamp plug- in for playback of over 40 chiptune and tracker formats.
  • VLC media player, a player for Windows / Mac / Linux, which reflects, among many other formats also SPC files.
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