22w: faithful mask-shaping chain v1 behind RT_FAITHFUL (fnfaith.cpp) — exact 180533340 freq-warped bidir-IIR coefficients (fc_bin=85@48k/4096, constants from dump); corpus TOTAL 5.315 but comb 2.57 best-ever; decisive: mask shape cannot balance dual tones -> level contrast is created by the DETECTOR (time-domain twin bank hypothesis priority #1)

dsp/framed_model.cpp

@@ -4,6 +4,7 @@
 #include "rt_mask_tables.hpp"
 #include "rt_weights.hpp"
 #include "fn529fe0.hpp"
+#include "fnfaith.hpp"
 #include <cmath>
 #include <cstring>
 #include <algorithm>
@@ -414,10 +415,22 @@ void FramedDetector::processFrame(const std::complex<double>* spectrum, float* m
     for (size_t k = 0; k <= half; k++) mask[k] = 1.0f;
 
     if (is_internal_grid(nfft_, sample_rate_)) {
+        // RT_FAITHFUL=1 (NOTES 22w): BLOCKMAP_529fe0 transcription path
+        static const int faithful = getenv("RT_FAITHFUL") ? atoi(getenv("RT_FAITHFUL")) : 0;
+        static const fnfaith::Params fparams = faithful ? fnfaith::params_from_env()
+                                                        : fnfaith::Params{};
+        // same scale_factor as process_band_structural (line ~79)
+        constexpr float sf = 15.0f * 440.95f / 2048.0f;
         for (size_t b = 0; b < bands_.size(); b++) {
             std::vector<float> band_mask(nfft_, 1.0f);
+            if (faithful) {
+                fnfaith::band_mask_faithful(am_.data(), res_[b].data(), half + 1,
+                                            sample_rate_, sf, fparams,
+                                            band_mask.data());
+            } else {
             process_band_structural(am_.data(), res_[b].data(), bands_[b],
                                     band_mask.data(), nfft_, sample_rate_);
+            }
             for (size_t k = 0; k <= half; k++) {
                 mask[k] = std::min(band_mask[k], mask[k]);
             }