VOCFMT0.TXT

If anyone wishes to update this file, please do so.  Just increment
the file # before reposting to give a chance at minimizing confusion..


VOC FILE FORMAT VERSION 1.10
============================

Header Block

Offset in bytes (HEX)
0h-13h  File Description, "Creative Voice File", 1Ah

14h-15h Offset of Data Block from start of file (in case header size changes)
        for now 1Ah

16h-17h Version #, for now 010Ah (vs 1.10)

18h-19h Identification code (test to verify this is VOC file)
        Complement of version # plus 1234h, currently 1129h

1Ah-    Start of Data Block (may change...)


Data Block is composed of multiple sub-blocks.
1st byte of EACH sub-block is type (BLKTYPE)
Next 3 bytes of ALL sub-blocks except type 0,
is 24-bit sub-block length (BLKLEN) in bytes (excluding 
BLKTYPE and BLKLEN fields), i.e. how many bytes left in sub-block
If your program doesn't handle a BLKTYPE, just skip BLKLEN more
bytes to get to next block.

BLOCK TYPE (fields following BLKLEN shown as field:length)
0  Has no length field.  Marks end of Data Block (EOF).

1  SR:1 PACK:1 DATA:BLKLEN-2
   SR (sampling rate), SR=256-1000000/rate, for 10,000HZ SR = 156
   PACK (compression method of DATA) 0-8bit raw, 1-4bit, 2-2.6bit, 3-2bit
   The compression modes are called ADPCM but I don't know how to
   pack/unpack them, most files floating about are the 8bit raw..

2  MoreData:BLKLEN
   Continues data from previous block

3  PERIOD:2 SR:1
   PERIOD+1 is length of silence. (in # of samples I believe)
   SR (sample rate) see above..

4  MARKER:2
   When encountered, driver sets flag.  Program may check for value   
   to synchronize with driver.

5  ASCII data:BLKLEN
   This must be a null-terminated string.
   (Ignore it, print it out, whatever..)

6  COUNT:2
   Repeat count.  Data blocks between this and next EndRepeat block
   should be repeated COUNT+1 times.
   COUNT = 0xFFFF means endless loop.
   I don't believe nested repeat blocks are allowed although they
   would be easy to implement..

7  EndRepeat (BLKLEN is 0)


I took the liberty of making this terse...  GOOD LUCK.