SFe 4.0 Release Candidate 3

[sylvia-leaf]

SFe 4.0 Release Candidate 3 (4.0-rc3)

This time I know it's for real

This isn't Donna Summer, but it's been decided that Release Candidate 3 will be the final version. There will no longer be changes. We've checked through the specification and everything is all good.

Adding the diagrams

We've added 12 figures (named figures 1 through 12) throughout the specification. These visually describe a wide variety of concepts from versioning to file structure. Like SFSPEC24.PDF, they are also accessible from the table of contents, which has recently been reintroduced (thanks to spessasus!).

Rewriting some parts of the specification to make it easier to read

Now, it is very easy to understand how the bank select logic required by SFe works. It starts with a structure that is split into subsections about how to use bank select MSB, the split of wBank into two, and using multiple percussion banks. Then, we added diagrams showing the structure of SFe banks in the file format. Finally, we added flowcharts to describe the process of selecting banks in SFe compared to that of legacy SF2.04.

Additionally, we consolidated a few more references to UTF-8 fields being used into one section.

The copyright and trademark disclaimers have also been moved to the beginning of the document, to make it more prominent. We want to make sure that users understand more clearly about these topics.

Because of these rewrites, section numbers have changed since RC2, so please ensure that the section numbers match.

SFSpecTest and feature flags

By using the open source SF spec test program by mrbumpy409, an SF author with more than 20 years of experience, and also the author of GeneralUser GS, one of the most legendary banks ever, you can determine whether your program is compliant with not only legacy SF2.04, but also basic elements of SFe.

We've added descriptions of all the tests that SFSpecTest does and the feature flags that correspond to each of the tests. The feature flags have also been modified to correspond more closely to the SFSpecTest tests. We also clarified that feature flag branches F0 to FF are private-use and may be used however you want, but reserved branches/leaves are not to be used as they are planned to be used in a future version.

ISO-8601 and ICRD sub-chunk

As you might know, the ICRD sub-chunk stores the creation date of an SFe or legacy SF2.04 bank. The problem is that it was initially intended for library management systems to allow sorting of banks according to creation date, but with internationalisation being more and more of a concern, program logic to handle ICRD values in different languages becomes more and more complicated.

To solve this issue, SFe now enforces a requirement for all ICRD values to be a valid ISO-8601 date, or a date and time. Library management systems in SFe programs can now check for such a date format, and then sort banks like that, without having to worry about different date and time formats that may have appeared in legacy SF2.04 banks.

64-bit chunk headers and versioning

The wMajor value is also once again equal to 4 when a 64-bit chunk header is detected. This means that programs can no longer rely on the wMajor value being greater than 2 to detect SFe Compression. Instead, programs must look for the compression bit in sfSampleType to detect the presence of SFe Compression.

Introducing SiliconSFe

The RC3 specification also includes SiliconSFe, the implementation of the SiliconSF format described in section 11 of SFSPEC24.PDF. The SiliconSF format was never adopted by other hardware vendors, and the documentation provided by Creative/E-mu was very ambiguous.

By analysing Creative's implementation of SiliconSF, we've written up a more detailed specification that attempts to describe how Creative intended the SiliconSF format to be used. Note that the implementation is different from the pure sample blobs that seem to have been used in the AWE ROMs.

About future plans

In two weeks, we will be doing a lot to prepare SFe for release.

• Firstly, we will create a test bank based on GeneralUser GS, which you can use to test SFe features early while developing software. It will showcase many, but not all of the features that SFe 4.0 has to offer.
• The next thing that we will do is to make a few changes to the specification to remove references to it being a release candidate. This is for obvious reasons.
• After that, we'll make a write-up about the upcoming SiliconSFe 1.0 format, based on SiliconSF and corresponding to SFe 4.0.

We will not release SFe 4.1 until there is at least one program supporting SFe 4.0 (level 1), because we want to make sure that the SFe specification remains still for enough time for software developers to target a specific version. However, development will be starting on not only SFe 4.1, but also SFe 5, the first version not to be 100% compatible with SFe 4 and legacy SF2.04.

We will have the first SFe 4.1 draft milestone (4.1.1) available in February, because work on the major features is already completed and the feature freeze has been done. The feature freeze for SFe 4.2 will be happening shortly after 4.1 starts development, so if you have any ideas for features that we could add in SFe 4.2, please submit them soon!

A recap of future versions:

• 4.1 includes DMOD and PNMM.
• 4.2 includes first new generator enums, SFCF, MIDI lyrics, RMIDI and SFLIST.
• 4.3 includes prsw, extended MIDI resets, filter upgrades, ISMI and IPRI.
• 4.4 includes the first DLS features beyond SFCF, SiliconSFe 1.1 featuring AL2, and IBAG/PBAG override.
• 4.5 includes dynamic RIFF by spessasus and full chunk override.
• 4.6 includes SFZ-based abstraction levels AL3-AL5.
• 4.7 includes conditional start/key switching.

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What's Changed

• Create code-of-conduct.md by @sylvia-leaf in Create code-of-conduct.md #75
• Update to RC2a by @sylvia-leaf in Update to RC2a #76
• Updating to Pre-RC3. by @sylvia-leaf in Updating to Pre-RC3. #85
• Generate TOC by @spessasus in Generate TOC #87
• Update dev branch for probably the final time. by @sylvia-leaf in Update dev branch for probably the final time. #93
• Incorrect branch fix by @sylvia-leaf in Incorrect branch fix #95
• The actual RC3 by @sylvia-leaf in The actual RC3 #96
• Update contributing.md by @sylvia-leaf in Update contributing.md #97
• Move RC3 to main by @sylvia-leaf in Move RC3 to main #98

Full Changelog: 4.0-rc2...4.0-rc3

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This discussion was created from the release SFe 4.0 Release Candidate 3.