Amiga MOD Packers Described - ProPacker 2.1 Described

Format name : ProPacker 2.1
Created by : C Estrup / Static Bytes (1991)

Sources :
* "Realtime Margherita" demo by Arise
* "Meetro" demo by Balance
* "Dementro" intro by BetaTeam
* "Prototype" demo by BetaTeam
* "Fire And Ice" music disk by BetaTeam
* 5 PP21 files sent by Gryzor (Thx !)

The following is repeated 31 times
with 8 bytes description for one sample

OFFSET	SIZE (bytes)	COMMENT
0 2 3 4 6	2 1 1 2 2	- Sample Size / 2 - Finetune (0->Fh) - Volume (0->40h) - Loop Size / 2 - Loop Start / 2

F8h
F9h
FAh
-
-
-
-
-
2FAh
-
-
2FAh+
128*NOP
2FAh+4
128*NOP
-
-
-
-
-
-
-
-
-

1
1
200h
-
-
-
-
-
128*NOP
-
-
4
-
SIZ
-
-
-
-
-
-
-
-
-
-

- (NOP) Number of pattern to play
- NoiseTracker byte (set to 7Fh)
- Tracks table. In fact, it's four (4) tables of 128 (80h) bytes each, where 128 is the number of pattern position. So, it's four tables for the four voices. These tables contain the numbers of tracks for each voice. (1st value is 0)
- Tracks "data". It's 64 values (2 bytes each) which refer to the following table. (1st value is 0)
- (SIZ) Size of the "reference table"
-
- "Reference table". Hard to find a name in fact :(. Well, this table contains the real tracks data. It's filled with the standard ptk four bytes description for one note. As an example, let's suppose the Track "data" value is 00-01, then, its real value will be the second block of four bytes in this table. A quick calculation shows that it can be very expensive because there's around 4,5 million possibilities ... (36*31*16*256)

each note is 4 bytes long

Note Packing (like PTK):

        -note value
       /           \
      |             |                 
 0000 0000  0000 0000  0000 0000  0000 0000  
 ||||                  |  | |  |  |       |
 ||| \                 | /   \/    \     /
 |||  \--Sample number--/  effect   effect
 \|/                               parameter
  \
   --unused

Follow Sample datas stored like Protracker. Nothing is packed..