HES

From ArchaicPixels: HuC and PCEAS Documentation

The HES file format is used for storing the PC Engine program data responsible for playing music and sound effects, similar in concept to SID and NSF. The format does not allow for meta-data such as song lengths, titles, or even the number of valid songs contained in an HES. Presumably, the HES format was designed with the use of an external pregenerated playlist in mind.

To begin playing a song after the file is loaded, load the song number into the 'A' register of the HuC6280, load the 8 MPRs, and call the initialization address.

A HES file consists of one 16-byte header, followed by one or more data header and chunk combinations.

The 16-bit "words" and the 32-bit "dwords" are stored in little-endian format.

Offset:	Type:	Description:
$0000	4 bytes	Magic string 'HESM'
$0004	byte	Version
$0005	byte	Starting song number
$0006	word	Initialization Address
$0008	byte	Initial MPR0
$0009	byte	Initial MPR1
$000A	byte	Initial MPR2
$000B	byte	Initial MPR3
$000C	byte	Initial MPR4
$000D	byte	Initial MPR5
$000E	byte	Initial MPR6
$000F	byte	Initial MPR7

Offset:	Type:	Description:
$0000	4 bytes	ID string 'DATA'
$0004	dword	Data chunk size(not including this 16-byte sub-header)
$0008	dword	Load address for this data chunk
$000C	(Reserved for future use, should be 0)
$0010	'Data chunk size' bytes	Data to load into the emulated PCE's memory map.