Phase 4+5: WebAudio I/O shim + verify DAW checklist — live=export, order, fader, PDC, smoke

native_bridge/src/BuiltinFxChain.cpp

@@ -205,6 +205,23 @@ public:
     }
     bool setParam(const std::string& key, double value) override {
         if (key == "amount") { amount_ = value / 100.0; rebuild(); return true; }
+        if (key.compare(0, 4, "band") == 0) {
+            const size_t us = key.find('_', 4);
+            if (us != std::string::npos && us > 4) {
+                const int idx = std::atoi(key.c_str() + 4);
+                const std::string field = key.substr(us + 1);
+                if (idx >= 0 && idx < (int)bands_.size()) {
+                    Band& b = bands_[idx];
+                    if (field == "freq") b.freq = value;
+                    else if (field == "gain") b.gain = value;
+                    else if (field == "q") b.q = value;
+                    else if (field == "active") b.active = (value != 0.0);
+                    else return false;
+                    rebuild();
+                    return true;
+                }
+            }
+        }
         return false;
     }
 private:

native_bridge/src/RenderFxJob.cpp

@@ -1144,6 +1144,12 @@ struct RealtimeFxChain::Impl {
     };
     struct Chain { std::vector<Entry> entries; };
 
+    // SET_PARAM chờ chain swap (setParam tới trước setChain): worker áp sau
+    // khi swap — không mất param race lúc khởi động.
+    struct PendingParam { int slot; std::string key; double value; };
+    std::mutex pmutex_;                    // guards pending_
+    std::vector<PendingParam> pending_;
+
     std::mutex mutex_;               // guards chain_ / retired_
     std::shared_ptr<Chain> chain_;
     std::shared_ptr<Chain> retired_; // dtor deferred to the worker thread
@@ -1224,9 +1230,14 @@ void RealtimeFxChain::setParam(int slot, const std::string& key, double value) {
     if (!impl_) return;
     std::shared_ptr<Impl::Chain> c;
     { std::lock_guard<std::mutex> lk(impl_->mutex_); c = impl_->chain_; }
-    if (!c || slot < 0 || (size_t)slot >= c->entries.size()) return;
-    auto& e = c->entries[(size_t)slot];
-    if (e.bfx) e.bfx->setParam(key, value);
+    if (c && slot >= 0 && (size_t)slot < c->entries.size()) {
+        auto& e = c->entries[(size_t)slot];
+        if (e.bfx) e.bfx->setParam(key, value);
+        return;
+    }
+    // Chain chưa swap (SET_PARAM tới trước setChain) — stash, worker áp sau swap.
+    std::lock_guard<std::mutex> lk(impl_->pmutex_);
+    impl_->pending_.push_back({slot, key, value});
 }
 
 uint64_t RealtimeFxChain::chainGen() {
@@ -1325,6 +1336,16 @@ void RealtimeFxChain::Impl::workerLoop() {
             retired_ = std::move(chain_);  // old chain destroyed on THIS thread
             chain_ = std::move(next);
         }
+        {
+            // Áp param chờ (đăng ký trước khi chain tồn tại).
+            std::lock_guard<std::mutex> lk(pmutex_);
+            for (const auto& p : pending_) {
+                if (p.slot < 0 || (size_t)p.slot >= chain_->entries.size()) continue;
+                auto& e = chain_->entries[(size_t)p.slot];
+                if (e.bfx) e.bfx->setParam(p.key, p.value);
+            }
+            pending_.clear();
+        }
         gen_.fetch_add(1, std::memory_order_release);  // loop báo lại latency
     }
 #ifdef _WIN32