AOH :: UT.TXT|
Ultra Tracker File Format
<From the IBM "ultra150.zip" archive by Marc Schallehn, text file by
Muchael J. Sutter and update comments added by Marc Schallehn. -JH>
Mysterious's ULTRA TRACKER File Format
by FreeJack of The Elven Nation
(some additional infos on the new format (V1.4/5) by MAS -> * marked)
I've done my best to document the file format of Ultra Tracker (UT).
If you find any errors please contact me.
The file format has stayed consistent through the first four public releases.
At the time of this writting, Ultra Tracker is up to version 1.3
(* With version V1.4/5 there are some changes done in the format. *)
Thanks go to :
SoJa of YLYSY for help translating stuff.
Marc André Schallehn
Thanks for putting out this GREAT program.
Also thanks for the info on 16bit samples.
With all this crap out of the way lets get to the format.
Sample Structure :
Samplename : 32 bytes (Sample name)
DosName : 12 bytes (when you load a sample into UT,
it records the file name here)
LoopStart : dbl word (loop start point)
LoopEnd : dbl word (loop end point)
SizeStart : dbl word (see below)
SizeEnd : dbl word (see below)
volume : byte (UT uses a logarithmic volume setting, ranging from 0-255)
(* V1.4: uses linear Volume ranging from 0-255 *)
Bidi Loop : byte (see below)
FineTune : word (Fine tune setting, uses full word value)
8 Bit Samples :
The SizeStart is the starting offset of the sample.
This seems to tell UT how to load the sample into the Gus's onboard memory.
All the files I have worked with start with a value of 32 for the first sample,
and the previous SizeEnd value for all sample after that. (See Example below)
If the previous sample was 16bit, then SizeStart = (Last SizeEnd * 2)
Like the SizeStart, SizeEnd seems to tell UT where to load the sample into the
Gus's onboard memory. SizeEnd equal SizeStart + the length of the sample.
If a UT file had 3 samples, 1st 12000 bytes, 2nd 5600 bytes, 3rd 8000 byte.
The SizeStart and SizeEnd would look like this:
Sample SizeStart SizeEnd
1st 32 12032
2nd 12032 17632
3rd 17632 25632
Samples may NOT cross 256k boundaries. If a sample is too large to fit into the
remaining space, its Sizestart will equal the start of the next 256k boundary.
UT does keep track of the free space at the top of the 256k boundaries, and
will load a sample in there if it will fit.
Example : EndSize = 252144
If the next sample was 12000 bytes, its SizeStart would be 262144, not 252144.
Note that this leaves 10000 bytes unused. If any of the following sample could
fit between 252144 and 262144, its Sizestart would be 252144.
Say that 2 samples after the 12000 byte sample we had a sample that was only
5000 bytes long. Its SizeStart would be 252144 and its SizeEnd would be 257144.
This also applies to 16 Bit Samples.
16 Bit Samples :
16 bit samples are handled a little different then 8 bit samples.
The SizeStart variable is calculated by dividing offset (last SizeEnd)
by 2. The SizeEnd variable equals SizeStart + (SampleLength / 2).
If the first sample is 16bit, then SizeStart = 16.
sample1 = 8bit, 1000 bytes
sample2 = 16bit, 5000 bytes
sample1 SizeStart = 32
SizeEnd = 1032 (32 + 1000)
sample2 SizeStart = 516 (offset (1032) / 2)
SizeEnd = 3016 (516 + (5000/2))
If a 16bit sample is loaded into banks 2,3, or 4
the SizeStart variable will be
(offset / 2) + 262144 (bank 2)
(offset / 2) + 524288 (bank 3)
(offset / 2) + 786432 (bank 4)
The SizeEnd variable will be
SizeStart + (SampleLength / 2) + 262144 (bank 2)
SizeStart + (SampleLength / 2) + 524288 (bank 3)
SizeStart + (SampleLength / 2) + 786432 (bank 4)
BiDi Loop : (Bidirectional Loop)
UT takes advantage of the Gus's ability to loop a sample in several different
ways. By setting the Bidi Loop, the sample can be played forward or backwards,
looped or not looped. The Bidi variable also tracks the sample
resolution (8 or 16 bit).
The following table shows the possible values of the Bidi Loop.
Bidi = 0 : No looping, forward playback, 8bit sample
Bidi = 4 : No Looping, forward playback, 16bit sample
Bidi = 8 : Loop Sample, forward playback, 8bit sample
Bidi = 12 : Loop Sample, forward playback, 16bit sample
Bidi = 24 : Loop Sample, reverse playback 8bit sample
Bidi = 28 : Loop Sample, reverse playback, 16bit sample
Note : byte (See note table below)
SampleNumber : byte (Sample Number)
Effect1 : nib (Effect1)
Effect2 : nib (Effect2)
EffectVar : word (Effect variables)
The High order byte of EffectVar is the Effect variable for Effect1.
The Low order byte of EffectVar is the Effect variable for Effect2.
UT uses a form of compression on repetitive events. Say we read in the first
byte, if it = $FC then this signifies a repeat block. The next byte is the
repeat count. followed by the event structure to repeat.
If the first byte read does NOT = $FC then this is the note of the event.
So repeat blocks will be 7 bytes long : RepFlag : byte ($FC)
RepCount : byte
note : byte
samplenumber : byte
effect1 : nib
effect2 : nib
effectVar : word
Repeat blocks do NOT bridge patterns.
note value of 0 = pause
C-0 to B-0 1 to 12
C-1 to B-1 13 to 24
C-2 to B-2 26 to 36
C-3 to B-3 39 to 48
C-4 to B-4 52 to 60
Offset Bytes Type Description
0 15 byte ID block : should contain
(* V1.4: 'MAS_UTrack_V002')
(* V1.5: 'MAS_UTrack_V003')
15 32 AsciiZ Song Title
47 1 reserved This byte is reserved and
always contain 0;
(* V1.4: jump-value: reserved * 32;
space between is used for song
[reserved * 32] = RES ! )
48+RES 1 byte Number of Samples (NOS)
49+RES NOS * 64 SampleStruct Sample Struct (see Sample Structure)
Patt_Seq = 48 + (NOS * 64) + RES
Patt_Seq 256 byte Pattern Sequence
Patt_Seq+256 1 byte Number Of Channels (NOC) Base 0
Patt_Seq+257 1 byte Number Of patterns (NOP) Base 0
(* V1.5: PAN-Position Table
Length: NOC * 1byte
[0 left] - [0F right] )
NOC+Patt_Seq+258 varies EventStruct Pattern Data (See Event
The remainder of the file is the raw sample data. (signed)
That should about cover it. If you have any questions, feel free to e-mail
me at email@example.com
I can also be contacted on The UltraSound Connection (813) 787-8644
The UltraSound Connection is a BBS dedicated to the Gravis Ultrasound Card.
Also I'm the author of Ripper and Gvoc. If anyone has any questions or
problems, please contact me.
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