fix(engine): defer set_param ra worker thread, VST API khong goi tren audio thread

app/templates/index.html

@@ -51,7 +51,7 @@
     <script src="/static/js/services/promptTemplateManager.js?v=202607281039"></script>
     <script src="/static/js/services/undoRedoEngine.js?v=202607290941"></script>
     <script src="/static/js/services/chordTheory.js?v=202608211300"></script>
-    <script src="/static/js/app.precompiled.js?v=202608241041" defer></script>
+    <script src="/static/js/app.precompiled.js?v=202608241142" defer></script>
     <link rel="stylesheet" href="/static/css/styles.css?v=202607271016">
     <style>
         :root {

native_bridge/src/RenderFxJob.cpp

@@ -1228,6 +1228,7 @@ struct RealtimeFxChain::Impl {
     struct PendingParam { int slot; std::string key; double value; };
     std::mutex pmutex_;                    // guards pending_
     std::vector<PendingParam> pending_;
+    std::atomic<int> paramQueued_{0};      // wake worker: param chờ apply
 
     std::mutex mutex_;               // guards chain_ / retired_
     std::shared_ptr<Chain> chain_;
@@ -1304,20 +1305,19 @@ void RealtimeFxChain::process(float* inL, float* inR, uint32_t n) {
 }
 
 void RealtimeFxChain::setParam(int slot, const std::string& key, double value) {
-    // SET_PARAM (SHM control ring, Phase 2.8): áp dụng live vào builtin slot.
-    // VST3 param automation qua VST3 API — ponytail: them khi co nhu cau.
+    // SET_PARAM (SHM control ring, Phase 2.8): KHÔNG gọi VST API trên audio
+    // thread (chain.setParam chạy từ RealtimeFxLoop drain ctrl ring) —
+    // controller->setParamNormalized là COM call cross-thread với GUI pump,
+    // block ms→chục ms → out ring cạn → worklet underrun → crackle. Mọi
+    // param defer vào pending_, worker thread áp (builtin nhanh, VST3 an
+    // toàn) — audio thread chỉ push queue + notify.
     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()) {
-        auto& e = c->entries[(size_t)slot];
-        if (e.bfx) e.bfx->setParam(key, value);
-        else if (e.fx) e.fx->setParam(key, value);
-        return;
+    {
+        std::lock_guard<std::mutex> lk(impl_->pmutex_);
+        impl_->pending_.push_back({slot, key, value});
     }
-    // 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});
+    impl_->paramQueued_.fetch_add(1, std::memory_order_release);
+    impl_->qcv_.notify_all();
 }
 
 uint64_t RealtimeFxChain::chainGen() {
@@ -1405,29 +1405,54 @@ void RealtimeFxChain::Impl::workerLoop() {
         std::string job;
         {
             std::unique_lock<std::mutex> lk(qmutex_);
-            qcv_.wait(lk, [&]() { return quit_ || !q_.empty(); });
+            qcv_.wait(lk, [&]() {
+                return quit_ || !q_.empty() || paramQueued_.load(std::memory_order_acquire) > 0;
+            });
             if (quit_) break;
-            job = std::move(q_.front());
-            q_.erase(q_.begin());
-        }
-        std::shared_ptr<Chain> next = buildChain(job);  // slow: plugin load
-        {
-            std::lock_guard<std::mutex> lk(mutex_);
-            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);
-                else if (e.fx) e.fx->setParam(p.key, p.value);
+            if (!q_.empty()) {
+                job = std::move(q_.front());
+                q_.erase(q_.begin());
+            }
+        }
+        if (!job.empty()) {
+            std::shared_ptr<Chain> next = buildChain(job);  // slow: plugin load
+            {
+                std::lock_guard<std::mutex> lk(mutex_);
+                retired_ = std::move(chain_);  // old chain destroyed on THIS thread
+                chain_ = std::move(next);
+            }
+            gen_.fetch_add(1, std::memory_order_release);  // loop báo lại latency
+        }
+        {
+            // Áp param chờ trên WORKER thread (audio thread không bao giờ gọi
+            // VST API): queue trước swap áp vào chain mới; queue trong lúc
+            // chain tồn tại áp ngay, không cần đợi setChain.
+            std::vector<Impl::PendingParam> toApply;
+            {
+                std::lock_guard<std::mutex> lk(pmutex_);
+                if (!pending_.empty()) {
+                    toApply.swap(pending_);
+                    paramQueued_.store(0, std::memory_order_release);
+                }
+            }
+            if (!toApply.empty()) {
+                std::shared_ptr<Chain> c;
+                { std::lock_guard<std::mutex> lk(mutex_); c = chain_; }
+                if (c) {
+                    for (const auto& p : toApply) {
+                        if (p.slot < 0 || (size_t)p.slot >= c->entries.size()) continue;
+                        auto& e = c->entries[(size_t)p.slot];
+                        if (e.bfx) e.bfx->setParam(p.key, p.value);
+                        else if (e.fx) e.fx->setParam(p.key, p.value);
+                    }
+                } else {
+                    // Chain chưa tồn tại — stash lại, áp sau swap.
+                    std::lock_guard<std::mutex> lk(pmutex_);
+                    pending_.insert(pending_.begin(), toApply.begin(), toApply.end());
+                    paramQueued_.fetch_add((int)toApply.size(), std::memory_order_release);
+                }
             }
-            pending_.clear();
         }
-        gen_.fetch_add(1, std::memory_order_release);  // loop báo lại latency
     }
 #ifdef _WIN32
     CoUninitialize();