LV2 measurers: dB readings use omx-dsp's omx_lin_to_db_d (#87)

debian/control

@@ -12,7 +12,7 @@ Build-Depends: debhelper-compat (= 13),
                plugin-hostd-dev (>= 0.1.4),
                libomx-contract-dev (>= 2.10.1),
                libomx-clap-lv2-dev (>= 0.8.0),
-               libomxdsp-dev (>= 0.18.0)
+               libomxdsp-dev (>= 0.21.0)
 Standards-Version: 4.6.2
 Homepage: https://github.com/FreeMixer/plugin-qualify
 Rules-Requires-Root: no

native/Makefile

@@ -37,8 +37,8 @@ OMX_CONTRACT_VERSION := 2.10.1
 # the omx-clap-core whose LV2 feature provider `make deps` builds where no omx-clap-lv2-devel is installed: the
 # packages' floor
 OMX_CLAP_CORE_VERSION := 0.8.0
-# the omx-dsp headers that omx-clap-core's provider reads, at omx-clap-core's own floor
-OMX_DSP_VERSION := 0.18.0
+# the omx-dsp headers the measurers (omx_lin_to_db_d) and omx-clap-core's provider read: the packages' floor
+OMX_DSP_VERSION := 0.21.0
 
 ifeq ($(shell $(PKG_CONFIG) --exists clap && echo true),true)
 CLAP_CFLAGS ?= $(shell $(PKG_CONFIG) --cflags clap)
@@ -58,6 +58,14 @@ else
 OMX_CONTRACT_CFLAGS ?= -Ideps/omx-contract/include
 endif
 
+# omx-dsp's headers, the level conversions the measurers call (omx_lin_to_db_d): the installed omx-dsp-devel /
+# libomxdsp-dev, else the headers `make deps` fetches
+ifeq ($(shell $(PKG_CONFIG) --exists omxdsp && echo true),true)
+OMX_DSP_CFLAGS ?= $(shell $(PKG_CONFIG) --cflags omxdsp)
+else
+OMX_DSP_CFLAGS ?= -Ideps/omx-dsp/include
+endif
+
 # the LV2 host features: <omx-clap-lv2/omx_lv2_features.h> and the static libomx-clap-lv2
 ifeq ($(shell $(PKG_CONFIG) --exists omx-clap-lv2 && echo true),true)
 OMX_CLAP_LV2_CFLAGS ?= $(shell $(PKG_CONFIG) --cflags omx-clap-lv2)
@@ -97,15 +105,15 @@ LV2_MEASURE_HDR := lv2-measure-options.h lv2-measure-pin.h lv2-measure-path.h rt
 
 # as openmixer built it: no FMA contraction, so a figure is the same on every architecture and compiler
 $(BUILD)/lv2_measure: $(LV2_MEASURE_SRC) $(LV2_MEASURE_HDR) | $(BUILD)
-	$(CC) $(CPPFLAGS) $(CFLAGS) -ffp-contract=off $(OMX_CONTRACT_CFLAGS) $(PLUGIN_HOSTD_CFLAGS) $(OMX_CLAP_LV2_CFLAGS) $(LILV_CFLAGS) \
+	$(CC) $(CPPFLAGS) $(CFLAGS) -ffp-contract=off $(OMX_CONTRACT_CFLAGS) $(OMX_DSP_CFLAGS) $(PLUGIN_HOSTD_CFLAGS) $(OMX_CLAP_LV2_CFLAGS) $(LILV_CFLAGS) \
 		$(LDFLAGS) -o $@ $(LV2_MEASURE_SRC) $(OMX_CLAP_LV2_LIBS) $(LILV_LIBS) -lpthread -lm -ldl
 
 # the same, under AddressSanitizer: the leak check runs it on every way out of main
 asan: $(BUILD)/asan/lv2_measure
 
 $(BUILD)/asan/lv2_measure: $(LV2_MEASURE_SRC) $(LV2_MEASURE_HDR) | $(BUILD)
 	mkdir -p $(@D)
-	$(CC) $(CPPFLAGS) $(CFLAGS) -fsanitize=address -fno-omit-frame-pointer -ffp-contract=off $(OMX_CONTRACT_CFLAGS) $(PLUGIN_HOSTD_CFLAGS) \
+	$(CC) $(CPPFLAGS) $(CFLAGS) -fsanitize=address -fno-omit-frame-pointer -ffp-contract=off $(OMX_CONTRACT_CFLAGS) $(OMX_DSP_CFLAGS) $(PLUGIN_HOSTD_CFLAGS) \
 		$(OMX_CLAP_LV2_CFLAGS) $(LILV_CFLAGS) $(LDFLAGS) -o $@ $(LV2_MEASURE_SRC) $(OMX_CLAP_LV2_LIBS) $(LILV_LIBS) -lpthread -lm -ldl
 
 # the feature options' oracle, never installed
@@ -118,7 +126,7 @@ $(BUILD)/lv2_measure_path_test: lv2_measure_path.test.c lv2-measure-path.c lv2-m
 	$(CC) $(CPPFLAGS) $(CFLAGS) -Werror -I. $(LDFLAGS) -o $@ lv2_measure_path.test.c lv2-measure-path.c
 
 $(BUILD)/lv2_host_probe: lv2-host-probe.c | $(BUILD)
-	$(CC) $(CPPFLAGS) $(CFLAGS) $(LILV_CFLAGS) $(LDFLAGS) -o $@ $< $(LILV_LIBS) -lpthread -lm
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(OMX_CONTRACT_CFLAGS) $(OMX_DSP_CFLAGS) $(LILV_CFLAGS) $(LDFLAGS) -o $@ $< $(LILV_LIBS) -lpthread -lm
 
 $(BUILD)/rt_interpose.so: rt-interpose.c rt-interpose.h | $(BUILD)
 	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -shared -fPIC -o $@ $< -ldl -lpthread

native/lv2-host-probe.c

@@ -32,6 +32,7 @@
 #include <string.h>
 
 #include <lilv/lilv.h>
+#include <omxdsp/omx_units.h> /* omx_lin_to_db_d */
 #include <lv2/core/lv2.h>
 #include <lv2/worker/worker.h>
 
@@ -85,7 +86,8 @@ static double level_db_at(const float *x, uint32_t from, uint32_t n, double hz)
     im += (double)x[from + i] * sin(w);
   }
   const double mag = 2.0 * sqrt(re * re + im * im) / (double)n;
-  return 20.0 * log10(mag < 1e-12 ? 1e-12 : mag);
+  /* a NaN magnitude stays NaN: the floor would read it as silence, and silence passes 'quieter' */
+  return isnan(mag) ? mag : omx_lin_to_db_d(mag, 1e-12);
 }
 
 /* ---- the host's worker ------------------------------------------------------------------
@@ -324,6 +326,7 @@ int main(int argc, char **argv) {
          (double)from / RATE, (double)end / RATE, HOT_HARMONIC, e, b, e - b);
   printf("  steady neighbour H3: %.2f dB\n", h3e - h3b);
 
+  claim(isfinite(e) && isfinite(b) && isfinite(h3e) && isfinite(h3b), "every level measured is a number (no NaN in the window)");
   claim(e - b < -1.0, "the engaged plugin is measurably quieter at the resonance");
   claim(fabs(h3e - h3b) < 1.5, "and leaves the steady neighbour alone");
   claim(memcmp(g_in, g_bypassed, FRAMES * sizeof(float)) == 0,

native/lv2-measure.c

@@ -67,6 +67,7 @@
 #include "lv2-measure-path.h"
 #include "lv2-measure-pin.h"
 #include <omxcontract/omx_contract_limits.h>
+#include <omxdsp/omx_units.h> /* omx_lin_to_db_d */
 #include <lv2/atom/atom.h>
 
 /*
@@ -884,7 +885,7 @@ int main(int argc, char **argv) {
         if (rms < min_rms) min_rms = rms;
         if (rms > max_rms) max_rms = rms;
         /* Dead relative to what this plugin was doing at the start: a ratio. */
-        if (first_rms > 0 && rms > 0 && 20.0 * log10(rms / first_rms) < -40.0) silent_windows++;
+        if (first_rms > 0 && rms > 0 && omx_lin_to_db_d(rms / first_rms, 0.0) < -40.0) silent_windows++;
         else if (first_rms > 0 && rms == 0.0) silent_windows++;
         const long r = rss_kb();
         if (r > rss_max) rss_max = r;
@@ -902,10 +903,10 @@ int main(int argc, char **argv) {
            ",\"firstRmsDbfs\":%.2f,\"lastRmsDbfs\":%.2f,\"minRmsDbfs\":%.2f,\"maxRmsDbfs\":%.2f"
            ",\"rssStartKb\":%ld,\"rssMaxKb\":%ld,\"rssGrowthKb\":%ld}",
            soak_s, rate, block, windows, nonfinite_windows, silent_windows,
-           first_rms > 0 ? 20.0 * log10(first_rms) : -999.0,
-           last_rms > 0 ? 20.0 * log10(last_rms) : -999.0,
-           min_rms < 1e29 && min_rms > 0 ? 20.0 * log10(min_rms) : -999.0,
-           max_rms > 0 ? 20.0 * log10(max_rms) : -999.0,
+           first_rms > 0 ? omx_lin_to_db_d(first_rms, 0.0) : -999.0,
+           last_rms > 0 ? omx_lin_to_db_d(last_rms, 0.0) : -999.0,
+           min_rms < 1e29 && min_rms > 0 ? omx_lin_to_db_d(min_rms, 0.0) : -999.0,
+           max_rms > 0 ? omx_lin_to_db_d(max_rms, 0.0) : -999.0,
            rss_start, rss_max, rss_max - rss_start);
     emit_host_facts(H);
     emit_feature_options();
@@ -1128,7 +1129,7 @@ int main(int argc, char **argv) {
            "\"rms\":%.9g,\"rmsDbfs\":%.2f}",
            ri ? "," : "", r, ok ? "true" : "false",
            nonfinite ? "true" : "false", lat_frames, rms_out,
-           rms_out > 0 ? 20.0 * log10(rms_out) : -999.0);
+           rms_out > 0 ? omx_lin_to_db_d(rms_out, 0.0) : -999.0);
   }
   fprintf(jout, "}");
   emit_host_facts(H);

packaging/plugin-qualify.spec

@@ -23,7 +23,7 @@ BuildRequires: pkgconfig(lv2)
 BuildRequires: pkgconfig(plugin-hostd) >= 0.1.4
 BuildRequires: pkgconfig(omx-contract) >= 2.10.1
 BuildRequires: pkgconfig(omx-clap-lv2) >= 0.8.0
-BuildRequires: pkgconfig(omxdsp) >= 0.18.0
+BuildRequires: pkgconfig(omxdsp) >= 0.21.0
 
 Requires: nodejs >= 18
 Requires: python3

src/native-db-copies.test.ts

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright (C) 2026 Pau Aliagas <linuxnow@gmail.com>
+/**
+ * The dB conversions of the native tools are omx-dsp's (`omx_lin_to_db_d` in `<omxdsp/omx_units.h>`):
+ * a hand-written `log10(...)` or `pow(10, ...)` in `native/*.c` is a second copy of the library's
+ * maths (#87). Each line left is named below with the reason it stays, and an entry whose line is
+ * gone fails too, so the list never outlives what it excuses.
+ *
+ * A text scan, so the negative is preceded by a positive control that proves the pattern sees a hit.
+ */
+import { readFileSync, readdirSync } from "node:fs";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+import { describe, expect, it } from "vitest";
+
+const NATIVE = join(dirname(fileURLToPath(import.meta.url)), "..", "native");
+
+/** A call of log10/log10f, or pow/powf with base 10. */
+const DB_COPY = /\blog10f?\s*\(|\bpowf?\s*\(\s*10(?:\.0*)?f?\s*,/;
+
+/** `<file>: <the line, trimmed>` -> why it stays. */
+const ALLOWED: Record<string, string> = {
+  "lv2-host-probe.c: const double hot = pow(10.0, HOT_EXCESS_DB / 20.0);":
+    "dB to linear in double: omx-dsp has omx_db_to_lin in float only, which is not bit-identical; stays until a double twin exists (#87)",
+};
+
+function hits(src: Record<string, string>): string[] {
+  const out: string[] = [];
+  for (const [file, text] of Object.entries(src))
+    for (const line of text.split("\n")) {
+      const code = line.replace(/\/\*.*?\*\/|\/\/.*$/g, "");
+      if (DB_COPY.test(code)) out.push(`${file}: ${line.trim()}`);
+    }
+  return out;
+}
+
+const sources = (): Record<string, string> =>
+  Object.fromEntries(
+    readdirSync(NATIVE)
+      .filter((n) => n.endsWith(".c"))
+      .map((n) => [n, readFileSync(join(NATIVE, n), "utf8")]),
+  );
+
+describe("native dB conversions come from omx-dsp", () => {
+  it("positive control: the pattern sees a hand-written log10 and pow(10, ...), not a comment", () => {
+    expect(
+      hits({
+        "x.c": "  return 20.0 * log10(mag);\n  float g = powf(10.0f, db / 20.0f);\n  /* 20 * log10(x) */\n  double y = pow(2.0, 3.0);\n",
+      }),
+    ).toEqual(["x.c: return 20.0 * log10(mag);", "x.c: float g = powf(10.0f, db / 20.0f);"]);
+  });
+
+  it("native/*.c has no log10 or pow(10, ...) but the allowlisted lines", () => {
+    const found = hits(sources());
+    expect(found.filter((h) => !(h in ALLOWED))).toEqual([]);
+  });
+
+  it("every allowlisted line is still there, so the list excuses nothing gone", () => {
+    const found = new Set(hits(sources()));
+    expect(Object.keys(ALLOWED).filter((k) => !found.has(k))).toEqual([]);
+  });
+});