Mirror of http://snesmusic.org/files/spc_file_format.txt.
SPC File Format v0.30
=====================
Offset Size Description
------ ----- ------------------------------------------------------------------
00000h 33 File header "SNES-SPC700 Sound File Data v0.30"
00021h 2 26,26
00023h 1 26 = header contains ID666 information
27 = header contains no ID666 tag
00024h 1 Version minor (i.e. 30)
SPC700 Registers:
00025h 2 PC
00027h 1 A
00028h 1 X
00029h 1 Y
0002Ah 1 PSW
0002Bh 1 SP (lower byte)
0002Ch 2 reserved
ID666 Tag (text format):
0002Eh 32 Song title
0004Eh 32 Game title
0006Eh 16 Name of dumper
0007Eh 32 Comments
0009Eh 11 Date SPC was dumped (MM/DD/YYYY)
000A9h 3 Number of seconds to play song before fading out
000ACh 5 Length of fade in milliseconds
000B1h 32 Artist of song
000D1h 1 Default channel disables (0 = enable, 1 = disable)
000D2h 1 Emulator used to dump SPC:
0 = unknown
1 = ZSNES
2 = Snes9x
000D3h 45 reserved (set to all 0's)
ID666 Tag (binary format):
0002Eh 32 Song title
0004Eh 32 Game title
0006Eh 16 Name of dumper
0007Eh 32 Comments
0009Eh 4 Date SPC was dumped (YYYYMMDD)
000A2h 7 unused
000A9h 3 Number of seconds to play song before fading out
000ACh 4 Length of fade in milliseconds
000B0h 32 Artist of song
000D0h 1 Default channel disables (0 = enable, 1 = disable)
000D1h 1 Emulator used to dump SPC:
0 = unknown
1 = ZSNES
2 = Snes9x
000D2h 46 reserved (set to all 0's)
00100h 65536 64KB RAM
10100h 128 DSP Registers
10180h 64 unused
101C0h 64 Extra RAM (Memory region used when the IPL ROM region is set
to read-only)
Extended ID666 Format
=====================
Extended information is stored at the end of the SPC file as an IFF chunk
with an ID of "xid6". Items that can be stored in the ID666 tag without any
loss of data should not be stored in the extended area.
Offset Size Description
------ ---- ------------------------------------------------------------------
0 4 Chunk type "xid6"
4 4 Chunk size, not including header
Sub-chunk Header
----------------
Inside the chunk are sub-chunks. Each sub-chunk consists of a 4-byte header,
and possibly data. All data is 32-bit aligned. If the data stored doesn't
reach a 32-bit boundary, it will be padded with 0's.
Offset Size Description
------ ---- ------------------------------------------------------------------
0 1 ID - song name, length, etc.
1 1 Type - 0 means data is stored in the header
non-zero means data is stored after header
2 2 Length - if 'type' is non-zero, this contains the length of the
following data
Extended ID666 Items
--------------------
ID: 00-0F - Items from original ID666 tag
10-1F - Extended items
30-3F - Items related to playback
Type: Length - 'Type' contains a 0, and the tag item is saved in the 'Length'
of the sub-chunk header.
String - 'Type' contains a 1, and the tag item is stored as a null
terminated string (max 256 characters including null).
Currently, strings saved in SNESAmp use ANSI characters.
However, support for UNICODE may be added.
Integer - 'Type' contains a 4, and the tag item is stored as an integer
following the header. Currently all integer items are four
bytes.
Size: The minimum and maximum sizes of an item
ID Type Size Description
--- ------- ----- ------------------------------------------------------------
01h String 4-256 Song name
02h String 4-256 Game name
03h String 4-256 Artist's name
04h String 4-256 Dumper's name
05h Integer 4 Date song was dumped (stored as yyyymmdd)
06h Length 1 Emulator used
07h String 4-256 Comments
10h String 4-256 Official Soundtrack Title
11h Length 1 OST disc
12h Length 2 OST track (upper byte is the number 0-99, lower byte is an
optional ASCII character)
13h String 4-256 Publisher's name
14h Length 2 Copyright year
30h Integer 4 Introduction length (Lengths are stored in ticks. A tick is
31h Integer 4 Loop length 1/64000th of a second. The maximum
32h Integer 4 End length length is 383999999 ticks. The End can
33h Integer 4 Fade length contain a negative value.)
34h Length 1 Muted channels (a bit is set for each channel that's muted)
35h Length 1 Number of times to loop the loop section of the song
36h Integer 4 Amplification value to apply to output (65536 = Normal SNES)
This may seem like a messy way to implement a format, but I wanted to assure
something that would be easily expandible.
The source code to SNESAmp (available at http://www.alpha-ii.com) contains a
C++ class for reading and writing ID666 and xid6 tags.
