104 lines
4.3 KiB
Prolog
104 lines
4.3 KiB
Prolog
Amiga "StarTrekker" MOD format, by Bjorn Wessen (aka "Star Tracker" in english)
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"FLT4" sig version = same as "M.K." Amiga NoiseTracker files.
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"FLT8" sig ver = same as "M!K!" Amiga ProTracker files but with 8 channels.
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From "GUSTRACK.DOC" of gustr103.zip (IBM GusTrack v1.03by EJ Botterman jr):
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File Formats:
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GusTrack will read 4 track ProTracker files and also Star Tracker files.
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( ID's M.K. and FLT4 )
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And it will read 8 Track Mod files made with Tritons Fast Tracker the
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Star Tracker or the Octalyzer.
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( ID's 8CHN, FLT8 and OCTA)
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( Does anyone know if the FLT8 format really excists ?)
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[EJ's Fido Address: 2:285/306.4 (Multi-Byte BBS)]
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Version of StarTrekker as of 1991:
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StarTrekker v1.2
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From Stefan Danes <sdanes@marvels.hacktic.nl>:
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>StarTrekker 4 & 8 channel
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Synth Format: No info, only that it uses 'EXO4' and 'EXO8' as ID strings
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Mod Format:
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4 Channels. FileFormat is identical to the original 4 Channel, 31 Samples
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mod format by Mahony & Kaktus, but uses 'FLT4' as ID string instead of 'M.K.'
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8 Channel 'FLT8': Like in 'FLT4' but: Divide all patterns in the orderlist
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by 2, and each pattern has an additional 400h bytes:
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Normal 4 channel Pattern 400h bytes:
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Ch1,Ch2,Ch3,Ch4 [Row 00h]
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... [Row ...]
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Ch1,Ch2,Ch3,Ch4 [Row 3Fh]
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Additional 400h bytes for 'FLT8':
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Ch5,Ch6,Ch7,Ch8 [Row 00h]
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... [Row ...]
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Ch5,Ch6,Ch7,Ch8 [Row 3Fh]
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From Bjoern Wesen <f92bw@efd.lth.se>:
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(Text below written in Nov, 1993)
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Hi. You asked for the formats for >6 channel modules. since i wrote
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StarTrekker, I can describe its 8 channel format. its very simple. just take
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two 4 channel patterns together! So pattern 0 and 1 is one 8 channel pattern.
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...
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At the same place in the module as the M.K., there is a FLT8 instead if
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its a 8 channel startrekker module. Startrekker itself is kinda outdated,
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so I would advise you to skip supporting it.
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...
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First, since the amiga is not an 8 channel computer, I would
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not recommend ANY 8 channel format. At least on a 68000, the realtime
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mixing does not sound very good, and there's little time for doing effects.
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So, in answer to your question of ProTracker compatibility, I'd say nope.
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You see, StarTrekker came just after NoiseTracker (me being a good friend
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to Mahoney and Kaktus) that is BEFORE protracker.
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As for the mixing... Basically I use a buffer, which is so long and plays
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at the right speed to make the buffer sound for 1/50 second. So while
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the buffer plays I calculate the next buffer. That way the processor dont
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have to be timed. If you have a speedier processor you could calculate with
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quadruple or more accuracy, say you conneyct a 16bit D/A on the pararllell
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port or something, then you could play 8 16bit channels on 44khz.
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However all this boils down to composing only. For games and demos, where
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the music is REALLY used, you cant afford having the processor calculate
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the music half the time.
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For the mixing of the buffer, I have a separate buffer for each of the 4
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native channels. So I mix two channels into one, by simply sliding
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through the two samples, picking the right samples for the speed the
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sample should be played in, adding them, scaling the result and putting
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into the buffer. You COULD interpolate also to get even better result but
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then you need again a speedier processor.
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(Text below written in March, 1994)
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In regards of the Amiga StarTrekker format:
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Since I wrote StarTrekker (once upon a time...) I think I may know the format.
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The format you are looking for is FLT8, and the ONLY two differences are:
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It says FLT8 instead of FLT4 or M.K., AND, the patterns are PAIRED. I thought
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this was the easiest 8 track format possible, since it can be loaded in a
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normal 4 channel tracker if you should want to rip sounds or patterns. So,
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in a 8 track FLT8 module, patterns 00 and 01 is "really" pattern 00. Patterns
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02 and 03 together is "really" pattern 01. Thats it. Oh well, I didnt have the
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time to implement all effect commands either, so some FLT8 modules would play
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back badly (I think especially the portamento command uses a different "scale"
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than the normal portamento command, that would be hard to patch).
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See ya...
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/Bjorn Wesen (Exolon of FairLight)
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