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H-Sound Engine: Difference between revisions

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The instrument format is N-SPC/Kankichi-kun compatible minus noise support for SRCN values above 127.
The instrument format is N-SPC/Kankichi-kun compatible minus noise support for SRCN values above 127.


The instrument format is defined as direct writes to DSP registers for the first four bytes, followed by two pitch-related bytes. They are defined in this order, from top to bottom...
The instrument format is defined as the following bytes...
* SRCN
<pre>xx yy zz aa bb cc dd</pre>
* ADSR1
* <tt>xx</tt> is a direct write to the VxSRCN DSP register.
* ADSR2
* <tt>yy</tt> is a direct write to the VxADSR1 DSP register.
* GAIN
* <tt>zz</tt> is a direct write to the VxADSR2 DSP register.
* Pitch Base Multiplier
* <tt>aa</tt> is a direct write to the VxGAIN DSP register.
* Pitch Base Fractional Multiplier (in 256ths)
* <tt>bb</tt> is a pitch base multiplier.
* <tt>cc</tt> is a fractional pitch base multiplier, defined in 256ths.


==Header Format==
==Header Format==

Revision as of 22:21, 14 March 2021

H-Sound is a sound engine created by Tsutomu Hagiwara of Sol for the SPC700 [1] [2]. The sound driver was used in five games.

Only one version, 0.5, was ever used. However, there are technically three different builds, each with very minor differences:

  • Yuujin no Furi Furi Girls, compared to Kamen Rider SD, has extra valid percussion note slots and a single extra opcode that overwrites the timer value to use at the start, thus almost not even qualifying as a build variant.
  • The other three games, compared to Kamen Rider SD, are missing an optional inversion operation for the echo volume. This is not controlled by a VCMD within the song.
Game Name Build ID VCMD Table Location ($E0 and up) ROM Offset
Kamen Rider SD 1 0x0C3D 0x0C9B91
Yuujin no Furi Furi Girls 2 0x0C45 0x888000
Hisshou Pachi-Slot Fun 3 0x0C69 0x088000
Honkakuha Igo - Gosei 3 0x0C69 0x0C8000
Janyuuki Gokuu Randa 3 0x0C69 0x1D8000

The raw build sorting notes can be found here.

Communication with the SNES

TODO document this

Instrument Format

The instrument format is N-SPC/Kankichi-kun compatible minus noise support for SRCN values above 127.

The instrument format is defined as the following bytes...

xx yy zz aa bb cc dd
  • xx is a direct write to the VxSRCN DSP register.
  • yy is a direct write to the VxADSR1 DSP register.
  • zz is a direct write to the VxADSR2 DSP register.
  • aa is a direct write to the VxGAIN DSP register.
  • bb is a pitch base multiplier.
  • cc is a fractional pitch base multiplier, defined in 256ths.

Header Format

Each song's header is a series of eight four byte entries, one per channel. Each entry contains the following bytes in order...

  • Two-byte little endian track pointer
  • Master track ID (Zero for music, non-zero for SFX)
  • Unused byte

Voice Command Format

VCMD ID Description Arguments
$00-$60 Note Length
$61-$71 Invalid Velocity
$72-$79 Velocity
$7A-$7F Quantization
$80-$C7 Note
$C8 Instant Slide To Note
$C9 Tie
$CA-$DF Percussion
$E0 Instrument xx
$E1 Panning xx
$E2 Note Volume xx
$E3 NOP xx
$E4 Pitch Offset xx
$E5 Absolute Transposition xx
$E6 Global Absolute Transposition xx
$E7 Loop Section Start
$E8 Loop Section End xx
$E9 Tempo xx
$EA NOP
$EB Activate Percussion Mode
$EC Echo On
$ED Echo Off
$EE ADSR xx yy
$EF GAIN xx
$F0-$F1 NOP
$F2 Jump xx xx
$F3 Noise Clock %???xxxxx
$F4 Noise On
$F5 Noise Off
$F6 Key Off On Quantization Elapse Enable
$F7 Key Off On Quantization Elapse Disable
$F8 FIR Coefficient Table ID xx
$F9 Echo Volume xx
$FA Echo Feedback xx
$FB-$FD NOP
$FE End of Track
$FF NOP

NOP (VCMD $E3, $EA, $F0-$F1, $FB-$FD, $FF)

Does absolutely nothing.

Note Length (VCMD $00-$60)

Defines a note length in tempo ticks plus one.

Invalid Velocity (VCMD $61-$71)

These are invalid VCMD IDs. They technically work, just that they read invalid velocity parameters as a side effect.

Velocity (VCMD $72-$79)

Refers to an array that contains a value to multiply by when combined with other volume parameters.

Quantization (VCMD $7A-$7F)

Refers to an array that contains a percentage in 256ths for how far along the note to play before keying it off in tempo ticks.

NOTE: This affects all channels due to a bug in its implementation (specifically, there's no indexed loading when calculating the number of ticks before keying off), and it only works when the first channel defines the quantization.

Note (VCMD $80-$C7)

Plays a note and delays the channel for one note length before reading another VCMD.

Instant Slide To Note (VCMD $C8)

Sets up the next note to not be keyed on and instead merely changes the pitch to the next note indicated. Other VCMDs can be processed first prior to the note being defined.

Tie (VCMD $C9)

Continues playing the previous note and delays the channel for one note length before reading another VCMD.

Percussion (VCMD $CA-$DF)

Plays a percussion note. Each percussion note takes up an instrument slot starting at a hardcoded fixed offset, and has a dedicated fixed pitch to play at referred to via a separate table.

Instrument (VCMD $E0)

$E0 xx
  • xx is an instrument ID to an array of instruments. See Instrument Format above for the format.

Panning (VCMD $E1)

$E1 xx
  • xx is the panning value. $00 is left, and $FF is right.

Note Volume (VCMD $E2)

$E2 xx
  • xx is the volume of the note.

Pitch Offset (VCMD $E4)

$E4 xx
  • xx defines the offset in units used for the VxPITCHH DSP registers. This is applied after multiplying out all of the other pitches.

Absolute Transposition (VCMD $E5)

$E5 xx
  • xx is a signed value defining the number of semitones to transpose subsequent notes.

Global Absolute Transposition (VCMD $E6)

$E6 xx
  • xx is a signed value defining the number of semitones to transpose subsequent notes. Note that this affects all channels, not just one channel.

Loop Section Start (VCMD $E7)

Defines a starting point for a loop section. No nesting is allowed.

Loop Section End (VCMD $E8)

$E8 xx
  • xx defines the number of times to go back to the loop section start marker.

Tempo (VCMD $E9)

$E9 xx
  • xx defines the tempo. One tempo is equal to one timer 0 tick multiplied by .

Activate Percussion Mode (VCMD $EB)

Causes standard notes to be invalid and percussion notes to be valid. Without using this VCMD, percussion notes are a NOP instead.

Echo On (VCMD $EC)

Activates echo for the channel.

Echo Off (VCMD $ED)

Disables echo for the channel.

ADSR (VCMD $EE)

$EE xx yy
  • xx is a direct write to the VxADSR1 register. The highest bit is automatically set to force ADSR mode.
  • yy is a direct write to the VxADSR2 register.

GAIN (VCMD $EF)

$EF xx

The highest bit in the VxADSR1 register is automatically cleared to force GAIN mode.

  • xx is a direct write to the VxGAIN register.

Jump (VCMD $F2)

$F2 xx xx

Noise Clock (VCMD $F3)

$F3 %???xxxxx
  • xxxxx defines the speed of the noise clock in five bits.

Noise On (VCMD $F4)

Activates noise for the channel.

Noise Off (VCMD $F5)

Disables noise for the channel.

Key Off On Quantization Elapse Enable (VCMD $F6)

This enables an automatic key off when a percentage of the note length defined by the quantization value has elapsed.

Key Off On Quantization Elapse Disable (VCMD $F7)

This disables an automatic key off when a percentage of the note length defined by the quantization value has elapsed.

FIR Coefficient Table ID (VCMD $F8)

$F8 xx
  • xx is an ID for a table of FIR coefficient IDs.

Echo Volume (VCMD $F9)

$F9 xx
  • xx defines the volume used for the EVOLL and EVOLR DSP registers.

Echo Feedback (VCMD $FA)

$FA xx
  • xx defines the value used for the EFB DSP register.

End of Track (VCMD $FE)

Stops the track from playing.