Section 9: SiliconSFe and the AWE ROM emulator

9.1 SiliconSFe overview

While we are unaware of any shipping products using the SiliconSF system found in SFSPEC24.PDF (the AWE cards used an early predecessor of SiliconSF), you can use ROM samples formatted in the SiliconSF format with SFe. However, SiliconSFe support is explicitly optional. (Update 5)

9.2 Header format

9.2.1 About the header format

The SiliconSFe header format is almost identical to legacy SF2.04, however an explanation is provided here due to poor documentation of SiliconSF.

Here is the SiliconSFe header format:

typedef struct romHdrType{
    DWORD romRiffHdr;
    DWORD romByteSize;
    CHAR romInterleaveIndex;
    CHAR romRevision[3];
    CHAR romVer[4];
    SHORT bankChecksum;
    SHORT bankChecksum2sComplement;
    CHAR bankSFeVersion;
    CHAR bankProduct[16];
    BYTE bankSampleCompType;
    CHAR filler1[2];
    CHAR bankStyle[16];
    CHAR bankCopyright[80];
    DWORD romSFeBankStart;
    DWORD romSineWaveStart;
    DWORD filler2[124];
    SHORT sampleSineWave[SINEWAVESIZE];
} romHdr;

9.2.2 romRiffHeader

In SiliconSFe, it is defined as the FourCC used by the chunk header type used by the integrated SF bank, for example RIFF, RIFS, RIFD, etc. (Update 17)

In the legacy SF2.04 specification, this is named romRsrc and was declared by Creative as “unused”. The name in SiliconSFe more accurately describes its usage.

9.2.3 romByteSize

This is an UNSIGNED DWORD value with the size of the SiliconSFe ROM blob in bytes. It is limited to 4 GiB in SiliconSFe 1.0. Signed integers are prohibited.

9.2.4 romInterleaveIndex

This is used for interleaved ROMs. You can interleave up to 256 ROMs with one SiliconSFe blob.

In the legacy SF2.04 specification, this is named interleaveIndex.

9.2.5 romRevision

This is a revision identifier as an integer. It is 3 bytes long and is independent of the version number found in romVer.

In the legacy SF2.04 specification, this is named revision.

9.2.6 romVer

This corresponds to the iver value in the integrated SF bank.

In the legacy SF2.04 specification, this is named id and is erroneously listed as corresponding to the irom value. The name in SiliconSFe more accurately describes its usage.

9.2.7 bankChecksum

This stores the CRC-16(ARC) checksum of the integrated SF bank.

In the legacy SF2.04 specification, this is named checksum.

9.2.8 bankChecksum2sComplement

This stores the twos-complement of the value found in bankChecksum.

In the legacy SF2.04 specification, this is named checksum2sComplement.

9.2.9 bankSFeVersion

This value should be the same as the wSFeSpecMajorVersion value in the SFvx sub-chunk in SFe, and the same as the wMajor value in the ifil sub-chunk in non-SFe. For an unknown or other format, this value is 0.

In the legacy SF2.04 specification, this is named bankFormat and was declared by Creative as “unused”.

9.2.10 bankProduct

This is a UTF-8 string that stores the product name (conventionally SiliconSFe).

In the legacy SF2.04 specification, this is named product.

9.2.11 sampleCompType

For the purpose of SiliconSFe, this value is 1 if any kind of sample precompensation is used, and 0 otherwise.

In the legacy SF2.04 specification, Creative said that it indicates the type of sample precompensation that is used in the SiliconSF blob.

9.2.12 bankStyle

This is a UTF-8 string that describes the musical style of the contents of the integrated SF bank.

In the legacy SF2.04 specification, this is named style.

9.2.13 bankCopyright

This is a UTF-8 string that stores copyright information about the SiliconSFe blob.

In the legacy SF2.04 specification, this is named copyright.

9.2.14 romSFeBankStart

This stores the location in the SiliconSFe blob where the integrated SF bank starts.

In the legacy SF2.04 specification, this is named sampleStart. The name in SiliconSFe more accurately describes its usage.

9.2.15 romSineWaveStart

This stores the location in the SiliconSFe blob where the test sine wave sample starts.

In the legacy SF2.04 specification, this is named sineWaveStart.

9.2.16 sampleSineWave

This contains SHORT values that correspond to a sine wave sample.

In the legacy SF2.04 specification, this is named sineWave.

9.3 AWE ROM emulator

9.3.1 Introducing the AWE ROM emulator

Except for when size concerns prohibit its inclusion, SFe players should include an AWE ROM emulator.

• The AWE ROM emulator includes 152 samples.
• The file size should be 1MB, as all samples should be to the same standard as the original.
• Samples which the program developer has the right to use can be used as a replacement for the original ROM samples.
• Freely-usable reference implementation samples are available, but are not intended for production use.
• Sample names will remain the same, but there will be acceptable alias names.
• Emulators should also be able to open up SF files (either legacy SF or SFe) containing samples and metadata.
• There may or may not be instruments or presets.

9.3.2 ROM emulator sample specification

Sample specification is fixed at 44.1khz Mono with no links and tuning at 60 with no fine-tuning. You can either use discrete samples, or create your own SiliconSFe ROM containing the emulator samples.