50 lines
1.3 KiB
Markdown
50 lines
1.3 KiB
Markdown
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# possible new Furnace instrument format
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the main issue with Furnace instrument files is that they are too big, even if the instrument is nothing more than the FM setup...
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the aim of this new format is to greatly reduce the size of a resulting instrument.
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```
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size | description
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-----|------------------------------------
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6 | "FURINS" format magic
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2 | format version
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1 | instrument type
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??? | feature bits
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4 | instrument length (if wave/sample bits are on)
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```
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the "feature bits" field is a variable length bitfield. bit 7 in a byte indicates "read one more byte".
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the feature bits are:
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- 0: has wavetables
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- 1: has samples
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- 2: has name
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- 3: FM data
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- 4: FM data size (1: 2-op, 0: 4-op)
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- 5: FM data includes OPL/OPZ data
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- if off, only read an op until ssgEnv.
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- if on, read everything else.
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- 6: Game Boy data
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- 7: (continue in next byte)
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- 8: C64 data
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- 9: Amiga data
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- 10: standard data (macros)
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- 11: operator macros
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- 12: release points
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- 13: op release points
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- 14: extended op macros
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- 15: (continue in next byte)
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- 16: OPL drums mode data
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- 17: Amiga sample map data
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- 18: Namco 163 data
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- 19: extra macros
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- 20: FDS data
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- 21: OPZ data
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- 22: wavetable synth data
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- 23: (continue in next byte)
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- 24: additional macro modes
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- 25: extra C64 data
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- 26: MultiPCM data
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