Reverse engineering: Use of ImHex and Pattern Files

[LuisMorenoSerrano]

Hi! My name is Luis, from Spain.

First of all, congratulations on your impressive work with the YSFC format!

Last Christmas I bought a Yamaha MODX M6 and I'm delighted with it. I recently started exploring its internal format as a hobby, with the idea of building a small tool for library performance manipulation (splitting, merging, etc.)—just something simple for organizing library content. Deep performance editing is not my goal, especially since Yamaha provides the Expanded Softsynth Plugin (ESP) for MODX M v3.0 for free.

A few days ago, I came across your project and found it incredibly interesting. I had already uncovered some information about the YSFC format, but reverse engineering is tough and time-consuming. Because of that, I've been working on a less painful way to analyze the files using ImHex and Pattern Files.

• ImHex web
• ImHex GitHub
• ImHex Pattern Language

I have read through your discoveries and tried to integrate them into my ImHex Pattern File. I would love to share it with you in case you find it useful. To try it out, you just need to open an Y2 file in ImHex from File -> Open File, then go to File -> Import -> Pattern File, click Browse..., and select the file I've attached.

Unfortunately, the pattern doesn't cover the entire format (yet), but I think it's a good starting point. I hope this small contribution will be useful to you, and I look forward to sharing any other discoveries I might make in the future.

Regards,

Luis Moreno

ysfc_y2.zip

[YSFCforge]

Hi Luis,

Thank you very much for reaching out, and for the kind words about the YSFC work.

Your ImHex Pattern File is a very interesting contribution. It complements my project quite well: YSFC Forge is mainly focused on parsing, manipulating, merging and eventually writing valid library files, while your pattern file gives a much more direct way to inspect the binary structure interactively in ImHex.

I especially like that you have mapped the YSFC header, catalogue/chunk directory, EPFM/DPFM structures, performance entries, waveform-related blocks and some of the Y2-specific structures. This could be very helpful when validating offsets, comparing files, checking unknown fields and documenting version differences.

My current focus has been on making the tools robust enough for real-world library manipulation, including dependencies and valid export. Your Pattern File looks like it could become a very useful companion tool for analysis and documentation, especially for fields that are still not fully understood.

Thanks again for sharing this. It is exactly the kind of contribution that can make this reverse-engineering work less painful and more useful for others.

Regards,
Johan