| > = 0072 + 2 * (filenameLength // 2) I'm having a hard time understanding what is meant by this. Particularly when 114 is the size of the patch after the 8 header bytes. The description also seems to get the word size wrong by treating the first 4 bytes as a NULL-terminated string. A 4-byte ID and a 4-byte big-endian length is almost universal for audio data. There's even a Python module[1] for it. And it's often nested, so within a chunk of data will be smaller chunks described the same way. The more complete and easier to analyze description of this patch would look like: "FORM" (114)
"PTCH"
"CAT " (4)
"REFS"
"DESC" (35)
[BC 01 03 00 00 FF] -- ?
(2) "17" -- File name
(19) "Scream 4 Distortion" -- Patch name
"PARM" (37)
[BC 01] -- Another BC01
(15) -- Number of params that follow
[01 01]
[02 3E]
[03 00]
[04 3E]
[05 1E]
[06 00]
[07 00]
[08 00]
[09 00]
[0A 00]
[0B 69]
[0C 28]
[0D 00]
[0E 00]
[0F 55]
[00]
"BODY" (0)
(In fact, "FORM" is the header used by AIFF files.)So a patch is a CAT, a DESC, a PARM, and a BODY (required even if not used). The number and meaning of parameters will depend on the type of effect, but from this we can guess they're all byte-sized, though a mix of signed and unsigned.
The 0 byte after the list is a bit of a mystery. The meanings of these parameters I assume was found by changing a value then seeing which byte changed in the file. The next step will be to compare a patch from a different effect. Even better to find one that makes use of the BODY section. Another fun way of reversing a format is to modify an unknown byte then see what happens when it is loaded. As for the way the website is presented, I think it would be helpful if the description activated by clicking on a byte instead of hovering. That would make it possible to then select and copy the description. (Truthfully, I'm increasingly convinced that hover effects in general are bad UX.) [1] https://docs.python.org/3/library/chunk.html |