bench: official param bridge (setparam/dump_params.lua) + rpp_setparam format tool; 22c — XML params decorative, depth=+-18dB, trim=+-24dB, reduction curves measured

scripts/rpp_setparam.py

@@ -0,0 +1,63 @@
+#!/usr/bin/env python3
+"""rpp_setparam.py — rewrite PARAM values inside a REAPER .rpp soothe2 state chunk.
+
+!!! CAVEAT (NOTES_LEVEL 22c): the XML <PARAM> list is a decorative UI-restore copy,
+NOT the VST3 state source. Editing values here does NOT change plugin audio behaviour
+(plugin falls back to defaults on any length mismatch). For real param changes use
+setparam.lua (TrackFX_SetParam bridge). This tool is kept for format surgery only.
+
+Block layout (joined from N consecutive base64 lines):
+  [u32 A=len(rest)][u32 ver=1]['VC2!'][u32 B=len(xml)][xml][tail: JUCEPrivateData...]
+Both length fields MUST be updated when xml size changes, otherwise the plugin
+silently rejects the state and falls back to defaults.
+
+Usage:
+  python3 scripts/rpp_setparam.py in.rpp out.rpp depth=1.0 release=0.5
+"""
+import re, base64, struct, sys
+
+
+def find_block(lines):
+    idx = [i for i, ln in enumerate(lines) if re.fullmatch(r"[A-Za-z0-9+/=]{40,}", ln.strip())]
+    start = None
+    for i in idx:
+        if base64.b64decode(lines[i].strip())[:1] == b"\x95":
+            start = i; break
+    if start is None:
+        raise SystemExit("no state block found")
+    end = start
+    while end + 1 < len(lines) and re.fullmatch(r"[A-Za-z0-9+/=]{40,}", lines[end + 1].strip()):
+        end += 1
+    return start, end
+
+
+def main():
+    inp, outp = sys.argv[1], sys.argv[2]
+    sets = dict(kv.split("=", 1) for kv in sys.argv[3:])
+    lines = open(inp).read().splitlines()
+    start, end = find_block(lines)
+    buf = b"".join(base64.b64decode(lines[k].strip()) for k in range(start, end + 1))
+    a, ver, magic, blen = struct.unpack_from("<II4sI", buf, 0)
+    i = buf.find(b"<?xml")
+    head, xml, tail = buf[:i], buf[i:i + blen], buf[i + blen:]
+    for k, v in sets.items():
+        pat = f'<PARAM id="{k}" value="'
+        j = xml.find(pat.encode())
+        assert j >= 0, f"param {k} not found"
+        v0 = j + len(pat)
+        e = xml.index(b'"/>', v0)
+        print(f"  {k}: {xml[v0:e].decode()} -> {v}")
+        xml = xml[:v0] + v.encode() + xml[e:]
+    new_blen = len(xml)
+    new_buf = struct.pack("<II4sI", a - blen + new_blen, ver, magic, new_blen) + xml + tail
+    ind = re.match(r"\s*", lines[start]).group(0)
+    width = max(len(lines[k]) - len(ind) for k in range(start, end + 1))
+    enc = base64.b64encode(new_buf).decode("ascii")
+    wrapped = [ind + enc[j:j + width] for j in range(0, len(enc), width)]
+    lines[start:end + 1] = wrapped
+    open(outp, "w").write("\n".join(lines) + "\n")
+    print(f"wrote {outp} (block {end-start+1}->{len(wrapped)} lines, xml {blen}->{new_blen})")
+
+
+if __name__ == "__main__":
+    main()