The Gravis Ultrasound Patch File Format

The Gravis Ultrasound Patch File Format

Also known as: GF1 Patch, PAT

Original Documentation

The GF1 Patch files are multipart sound files for the Gravis Ultrasound
sound card to emulate MIDI sounds in high quality. Each Patch can consist
of many samples (for example, a string ensemble consists of Violin, Viola,
Cello, Bass) which are played depending on the note to play. A patch can also
contain a part to be played before the loop and a part to be played after
the tone has been released.
OFFSET              Count TYPE   Description
0000h                  12 char   ID='GF1PATCH110'
000Ch                  10 char   Manufacturer ID
0018h                  60 char   Description of the contained Instruments
								 or copyright of manufacturer.
0054h                   1 byte   Number of instruments in this patch
0055h                   1 byte   Number of voices for sample
0056h                   1 byte   Number of output channels
0057h                   1 word   Number of waveforms
0059h                   1 word   Master volume for all samples
005Bh                   1 dword  Size of the following data
0060h                  36 byte   reserved

Following this header, the instruments with their headers follow.
An instrument header contains the name and other data about one
instrument contained within the patch.
OFFSET              Count TYPE   Description
0000h                   1 word   Instrument number. ?Maybe the MIDI instrument
								 number?. In the Gravis patches, this is 0, in
								 other patches, I found random values.
0002h                  16 char   ASCII name of the instrument.
0012h                   1 dword  Size of the whole instrument in bytes.
0016h                   1 byte   Layers. Needed for whatever.
0017h                  40 byte   reserved

About the patch, I don't know anything. Maybe somebody could enlighten me.
Each patch record has the following format :
OFFSET              Count TYPE   Description
0000h                   7 char   Wave file name
0007h                   1 byte   Fractions
0008h                   1 dword  Wave size.
								 Size of the wave digital data
000Ch                   1 dword  Start of wave loop
0010h                   1 dword  End of wave loop
0012h                   1 word   Sample rate of the wave
0014h                   1 word   Minimum frequency to play the wave
0016h                   1 word   Maximum frequency to play the wave
0018h                   1 dword  Original sample rate of the wave data
001Ch                   1 int    Fine tune value for the wave
001Eh                   1 byte   Stereo balance, values unknown**
001Fh                   6 byte   Filter envelope rate
0025h                   6 byte   Filter envelope offse
002Bh                   1 byte   Tremolo sweep
002Ch                   1 byte   Tremolo rate
002Dh                   1 byte   Tremolo depth
002Fh                   1 byte   Vibrato sweep
0030h                   1 byte   Vibrato rate
0031h                   1 byte   Vibrato depth
0032h                   1 byte   Wave data, bitmapped
								   0 - 8/16 bit wave data
								   1 - signed/unsigned data
								   2 - de/enable looping
								   3 - no/has bidirectional looping
								   4 - loop forward/backward
								   5 - Turn envelope sustaining off/on
								   6 - Dis/Enable filter envelope
								   7 - reserved
0033h                   1 int    Frequency scale, whatever that means
0035h                   1 word   Frequency scale factor
0037h                  36 byte   Reserved

PROGRAMS:Patch Maker

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