diff --git a/app/static/js/app.jsx b/app/static/js/app.jsx
index c582d62..0476150 100644
--- a/app/static/js/app.jsx
+++ b/app/static/js/app.jsx
@@ -5089,13 +5089,15 @@ const App = () => {
   }, [tracks, selectedTrackId, selLeft, selRight]);
 
   // ── Toast helper ──
-  const showToast = (text, type = 'info') => {
+  const showToast = (text, type = 'info', actionText = null, onActionClick = null) => {
     if (toastTimeoutRef.current) clearTimeout(toastTimeoutRef.current);
     setToastMessage({
       text,
-      type
+      type,
+      actionText,
+      onActionClick
     });
-    toastTimeoutRef.current = setTimeout(() => setToastMessage(null), 3500);
+    toastTimeoutRef.current = setTimeout(() => setToastMessage(null), actionText ? 8000 : 3500);
   };
 
   // ── Server-side upload ──
@@ -6605,12 +6607,63 @@ const App = () => {
         type: 'audio/wav'
       });
       const url = URL.createObjectURL(blob);
-      const a = document.createElement('a');
-      a.href = url;
-      a.download = `sonicforge-session-${targetRate}hz-${bitDepth}bit.wav`;
-      a.click();
+      if ((exportSettings.format === 'mp3' || exportSettings.format === 'ogg') && serverStatus === 'connected') {
+        setIsExporting(true);
+        showToast("Đang gửi yêu cầu nén định dạng lên máy chủ...", "info");
+        try {
+          const file = new File([blob], `session_export.wav`, { type: 'audio/wav' });
+          const formData = new FormData();
+          formData.append('file', file);
+          const uploadResp = await fetch(`${API_AUDIO}/upload`, {
+            method: 'POST',
+            body: formData
+          });
+          if (!uploadResp.ok) throw new Error("Upload to transcode server failed");
+          const uploadData = await uploadResp.json();
+          const fileId = uploadData.file_id;
+
+          const exportResp = await fetch(`${API_AUDIO}/export`, {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({
+              file_id: fileId,
+              format: exportSettings.format,
+              sample_rate: targetRate,
+              bit_depth: bitDepth
+            })
+          });
+          if (!exportResp.ok) throw new Error("Transcode request failed");
+          const exportData = await exportResp.json();
+          const result = await pollTaskResult(exportData.task_id, 20);
+          if (result.success) {
+            const outId = result.output_file_id;
+            const downloadUrl = `${API_AUDIO}/download/${outId}`;
+            const a = document.createElement('a');
+            a.href = downloadUrl;
+            a.download = `sonicforge-session-${targetRate}hz-${bitDepth}bit.${exportSettings.format}`;
+            a.click();
+            showToast(`Xuất bản âm thanh định dạng ${exportSettings.format.toUpperCase()} thành công!`, "success");
+          } else {
+            throw new Error(result.error || 'Server encoding failed');
+          }
+        } catch (transcodeErr) {
+          showToast(`Lỗi chuyển đổi: ${transcodeErr.message}. Tải dạng WAV thay thế.`, "warning");
+          const a = document.createElement('a');
+          a.href = url;
+          a.download = `sonicforge-session-${targetRate}hz-${bitDepth}bit.wav`;
+          a.click();
+        }
+      } else {
+        if (exportSettings.format !== 'wav') {
+          showToast("Đang ngoại tuyến. Tải về định dạng WAV thay thế.", "warning");
+        }
+        const a = document.createElement('a');
+        a.href = url;
+        a.download = `sonicforge-session-${targetRate}hz-${bitDepth}bit.wav`;
+        a.click();
+        showToast("Xuất bản âm thanh hoàn tất!", "success");
+      }
       URL.revokeObjectURL(url);
-      showToast("Xuất bản âm thanh hoàn tất!", "success");
     } catch (err) {
       showToast("Lỗi xuất âm thanh: " + err.message, "error");
     } finally {
@@ -7239,19 +7292,28 @@ const App = () => {
       }
       if (hasCalls) {
         setAiActionLog(prev => [...prev, { type: 'info', text: ` Gọi ${result.functionCalls.length} lệnh...`, time: Date.now() }]);
-        for (const fc of result.functionCalls) {
-          setAiActionLog(prev => [...prev, { type: 'info', text: ` Gọi lệnh: ${fc.name}(${JSON.stringify(fc.arguments)})`, time: Date.now() }]);
-          const cmdName = fc.name.toUpperCase();
-          if (window.DAWCommandDispatcher) {
-            try {
-              let cmdResult = window.DAWCommandDispatcher.execute(cmdName, fc.arguments);
-              if (cmdResult && typeof cmdResult.then === 'function') cmdResult = await cmdResult;
-              setAiActionLog(prev => [...prev, { type: 'status', text: ` ✅ ${fc.name}: ${cmdResult && cmdResult.success ? 'thành công' : 'thất bại: ' + ((cmdResult && cmdResult.error) || 'unknown')}`, time: Date.now() }]);
-            } catch (cmdErr) {
-              setAiActionLog(prev => [...prev, { type: 'error', text: ` ❌ ${fc.name}: ${cmdErr.message}`, time: Date.now() }]);
+        if (window.DAWCommandDispatcher) {
+          window.DAWCommandDispatcher.isExecutingAI = true;
+        }
+        try {
+          for (const fc of result.functionCalls) {
+            setAiActionLog(prev => [...prev, { type: 'info', text: ` Gọi lệnh: ${fc.name}(${JSON.stringify(fc.arguments)})`, time: Date.now() }]);
+            const cmdName = fc.name.toUpperCase();
+            if (window.DAWCommandDispatcher) {
+              try {
+                let cmdResult = window.DAWCommandDispatcher.execute(cmdName, fc.arguments);
+                if (cmdResult && typeof cmdResult.then === 'function') cmdResult = await cmdResult;
+                setAiActionLog(prev => [...prev, { type: 'status', text: ` ✅ ${fc.name}: ${cmdResult && cmdResult.success ? 'thành công' : 'thất bại: ' + ((cmdResult && cmdResult.error) || 'unknown')}`, time: Date.now() }]);
+              } catch (cmdErr) {
+                setAiActionLog(prev => [...prev, { type: 'error', text: ` ❌ ${fc.name}: ${cmdErr.message}`, time: Date.now() }]);
+              }
+            } else {
+              setAiActionLog(prev => [...prev, { type: 'error', text: ` ❌ ${fc.name}: DAWCommandDispatcher not available`, time: Date.now() }]);
             }
-          } else {
-            setAiActionLog(prev => [...prev, { type: 'error', text: ` ❌ ${fc.name}: DAWCommandDispatcher not available`, time: Date.now() }]);
+          }
+        } finally {
+          if (window.DAWCommandDispatcher) {
+            window.DAWCommandDispatcher.isExecutingAI = false;
           }
         }
       }
@@ -7782,13 +7844,76 @@ const App = () => {
             ofs += bps;
           }
         }
-        const blob = new Blob([fileBuf], { type: 'audio/' + fmt });
-        const url = URL.createObjectURL(blob);
-        const a = document.createElement('a');
-        a.href = url;
-        a.download = `export_${Date.now()}.${fmt}`;
-        a.click();
-        URL.revokeObjectURL(url);
+        const blob = new Blob([fileBuf], { type: 'audio/wav' });
+        const localUrl = URL.createObjectURL(blob);
+        const targetFilename = `export_${Date.now()}.${fmt}`;
+
+        const triggerDownload = (downloadUrl, finalFilename) => {
+          if (window.DAWCommandDispatcher?.isExecutingAI) {
+            showToast(`Xuất nhạc thành công (${fmt.toUpperCase()})!`, "success", "Tải về", () => {
+              const a = document.createElement('a');
+              a.href = downloadUrl;
+              a.download = finalFilename;
+              a.click();
+              if (downloadUrl.startsWith('blob:')) {
+                URL.revokeObjectURL(downloadUrl);
+              }
+            });
+          } else {
+            const a = document.createElement('a');
+            a.href = downloadUrl;
+            a.download = finalFilename;
+            a.click();
+            showToast("Xuất bản âm thanh hoàn tất!", "success");
+            if (downloadUrl.startsWith('blob:')) {
+              URL.revokeObjectURL(downloadUrl);
+            }
+          }
+        };
+
+        if ((fmt === 'mp3' || fmt === 'ogg') && serverStatus === 'connected') {
+          try {
+            const file = new File([blob], `export_ai.wav`, { type: 'audio/wav' });
+            const formData = new FormData();
+            formData.append('file', file);
+            const uploadResp = await fetch(`${API_AUDIO}/upload`, {
+              method: 'POST',
+              body: formData
+            });
+            if (!uploadResp.ok) throw new Error("Upload failed");
+            const uploadData = await uploadResp.json();
+            const uploadId = uploadData.file_id;
+
+            const exportResp = await fetch(`${API_AUDIO}/export`, {
+              method: 'POST',
+              headers: { 'Content-Type': 'application/json' },
+              body: JSON.stringify({
+                file_id: uploadId,
+                format: fmt,
+                sample_rate: sr,
+                bit_depth: bd
+              })
+            });
+            if (!exportResp.ok) throw new Error("Export failed");
+            const exportData = await exportResp.json();
+            const result = await pollTaskResult(exportData.task_id, 20);
+            if (result.success) {
+              const downloadUrl = `${API_AUDIO}/download/${result.output_file_id}`;
+              triggerDownload(downloadUrl, targetFilename);
+            } else {
+              throw new Error(result.error || 'Server encoding failed');
+            }
+          } catch (transcodeErr) {
+            showToast(`Lỗi chuyển đổi: ${transcodeErr.message}. Tải về dạng WAV thay thế.`, "warning");
+            triggerDownload(localUrl, `export_${Date.now()}.wav`);
+          }
+        } else {
+          const finalFilename = fmt === 'wav' ? `export_${Date.now()}.wav` : `export_${Date.now()}.wav`;
+          if (fmt !== 'wav') {
+            showToast("Đang ngoại tuyến. Tải về định dạng WAV thay thế.", "warning");
+          }
+          triggerDownload(localUrl, finalFilename);
+        }
         return { success: true, trackId: tid, range: parseFloat((rawEnd - rawStart).toFixed(3)) + 's', format: fmt, channels: numCh === 1 ? 'mono' : 'stereo' };
       },
       selectItem: (args) => {
@@ -10461,7 +10586,13 @@ const App = () => {
   }, /*#__PURE__*/React.createElement("i", {
     "data-lucide": "bell",
     className: `w-4 h-4 ${toastMessage.type === 'success' ? 'text-emerald-400' : toastMessage.type === 'error' ? 'text-rose-400' : toastMessage.type === 'warning' ? 'text-amber-400' : 'text-cyan-400'}`
-  })), toastMessage.text), /*#__PURE__*/React.createElement(AuthModal, {
+  })), toastMessage.text, toastMessage.onActionClick && /*#__PURE__*/React.createElement("button", {
+    onClick: () => {
+      toastMessage.onActionClick();
+      setToastMessage(null);
+    },
+    className: "ml-2 px-2 py-0.5 bg-purple-700 hover:bg-purple-600 text-white rounded text-[10px] uppercase font-bold"
+  }, toastMessage.actionText || 'Tải về')), /*#__PURE__*/React.createElement(AuthModal, {
     isOpen: authModalOpen,
     mode: authMode,
     forceMandatory: isMandatoryLogin,
diff --git a/app/static/js/app.precompiled.js b/app/static/js/app.precompiled.js
index 33827ba..b9bb597 100644
--- a/app/static/js/app.precompiled.js
+++ b/app/static/js/app.precompiled.js
@@ -5144,13 +5144,15 @@ const App = () => {
   }, [tracks, selectedTrackId, selLeft, selRight]);
 
   // ── Toast helper ──
-  const showToast = (text, type = 'info') => {
+  const showToast = (text, type = 'info', actionText = null, onActionClick = null) => {
     if (toastTimeoutRef.current) clearTimeout(toastTimeoutRef.current);
     setToastMessage({
       text,
-      type
+      type,
+      actionText,
+      onActionClick
     });
-    toastTimeoutRef.current = setTimeout(() => setToastMessage(null), 3500);
+    toastTimeoutRef.current = setTimeout(() => setToastMessage(null), actionText ? 8000 : 3500);
   };
 
   // ── Server-side upload ──
@@ -6738,12 +6740,66 @@ const App = () => {
         type: 'audio/wav'
       });
       const url = URL.createObjectURL(blob);
-      const a = document.createElement('a');
-      a.href = url;
-      a.download = `sonicforge-session-${targetRate}hz-${bitDepth}bit.wav`;
-      a.click();
+      if ((exportSettings.format === 'mp3' || exportSettings.format === 'ogg') && serverStatus === 'connected') {
+        setIsExporting(true);
+        showToast("Đang gửi yêu cầu nén định dạng lên máy chủ...", "info");
+        try {
+          const file = new File([blob], `session_export.wav`, {
+            type: 'audio/wav'
+          });
+          const formData = new FormData();
+          formData.append('file', file);
+          const uploadResp = await fetch(`${API_AUDIO}/upload`, {
+            method: 'POST',
+            body: formData
+          });
+          if (!uploadResp.ok) throw new Error("Upload to transcode server failed");
+          const uploadData = await uploadResp.json();
+          const fileId = uploadData.file_id;
+          const exportResp = await fetch(`${API_AUDIO}/export`, {
+            method: 'POST',
+            headers: {
+              'Content-Type': 'application/json'
+            },
+            body: JSON.stringify({
+              file_id: fileId,
+              format: exportSettings.format,
+              sample_rate: targetRate,
+              bit_depth: bitDepth
+            })
+          });
+          if (!exportResp.ok) throw new Error("Transcode request failed");
+          const exportData = await exportResp.json();
+          const result = await pollTaskResult(exportData.task_id, 20);
+          if (result.success) {
+            const outId = result.output_file_id;
+            const downloadUrl = `${API_AUDIO}/download/${outId}`;
+            const a = document.createElement('a');
+            a.href = downloadUrl;
+            a.download = `sonicforge-session-${targetRate}hz-${bitDepth}bit.${exportSettings.format}`;
+            a.click();
+            showToast(`Xuất bản âm thanh định dạng ${exportSettings.format.toUpperCase()} thành công!`, "success");
+          } else {
+            throw new Error(result.error || 'Server encoding failed');
+          }
+        } catch (transcodeErr) {
+          showToast(`Lỗi chuyển đổi: ${transcodeErr.message}. Tải dạng WAV thay thế.`, "warning");
+          const a = document.createElement('a');
+          a.href = url;
+          a.download = `sonicforge-session-${targetRate}hz-${bitDepth}bit.wav`;
+          a.click();
+        }
+      } else {
+        if (exportSettings.format !== 'wav') {
+          showToast("Đang ngoại tuyến. Tải về định dạng WAV thay thế.", "warning");
+        }
+        const a = document.createElement('a');
+        a.href = url;
+        a.download = `sonicforge-session-${targetRate}hz-${bitDepth}bit.wav`;
+        a.click();
+        showToast("Xuất bản âm thanh hoàn tất!", "success");
+      }
       URL.revokeObjectURL(url);
-      showToast("Xuất bản âm thanh hoàn tất!", "success");
     } catch (err) {
       showToast("Lỗi xuất âm thanh: " + err.message, "error");
     } finally {
@@ -7396,35 +7452,44 @@ const App = () => {
           text: ` Gọi ${result.functionCalls.length} lệnh...`,
           time: Date.now()
         }]);
-        for (const fc of result.functionCalls) {
-          setAiActionLog(prev => [...prev, {
-            type: 'info',
-            text: ` Gọi lệnh: ${fc.name}(${JSON.stringify(fc.arguments)})`,
-            time: Date.now()
-          }]);
-          const cmdName = fc.name.toUpperCase();
-          if (window.DAWCommandDispatcher) {
-            try {
-              let cmdResult = window.DAWCommandDispatcher.execute(cmdName, fc.arguments);
-              if (cmdResult && typeof cmdResult.then === 'function') cmdResult = await cmdResult;
-              setAiActionLog(prev => [...prev, {
-                type: 'status',
-                text: ` ✅ ${fc.name}: ${cmdResult && cmdResult.success ? 'thành công' : 'thất bại: ' + (cmdResult && cmdResult.error || 'unknown')}`,
-                time: Date.now()
-              }]);
-            } catch (cmdErr) {
+        if (window.DAWCommandDispatcher) {
+          window.DAWCommandDispatcher.isExecutingAI = true;
+        }
+        try {
+          for (const fc of result.functionCalls) {
+            setAiActionLog(prev => [...prev, {
+              type: 'info',
+              text: ` Gọi lệnh: ${fc.name}(${JSON.stringify(fc.arguments)})`,
+              time: Date.now()
+            }]);
+            const cmdName = fc.name.toUpperCase();
+            if (window.DAWCommandDispatcher) {
+              try {
+                let cmdResult = window.DAWCommandDispatcher.execute(cmdName, fc.arguments);
+                if (cmdResult && typeof cmdResult.then === 'function') cmdResult = await cmdResult;
+                setAiActionLog(prev => [...prev, {
+                  type: 'status',
+                  text: ` ✅ ${fc.name}: ${cmdResult && cmdResult.success ? 'thành công' : 'thất bại: ' + (cmdResult && cmdResult.error || 'unknown')}`,
+                  time: Date.now()
+                }]);
+              } catch (cmdErr) {
+                setAiActionLog(prev => [...prev, {
+                  type: 'error',
+                  text: ` ❌ ${fc.name}: ${cmdErr.message}`,
+                  time: Date.now()
+                }]);
+              }
+            } else {
               setAiActionLog(prev => [...prev, {
                 type: 'error',
-                text: ` ❌ ${fc.name}: ${cmdErr.message}`,
+                text: ` ❌ ${fc.name}: DAWCommandDispatcher not available`,
                 time: Date.now()
               }]);
             }
-          } else {
-            setAiActionLog(prev => [...prev, {
-              type: 'error',
-              text: ` ❌ ${fc.name}: DAWCommandDispatcher not available`,
-              time: Date.now()
-            }]);
+          }
+        } finally {
+          if (window.DAWCommandDispatcher) {
+            window.DAWCommandDispatcher.isExecutingAI = false;
           }
         }
       }
@@ -8110,14 +8175,78 @@ const App = () => {
           }
         }
         const blob = new Blob([fileBuf], {
-          type: 'audio/' + fmt
+          type: 'audio/wav'
         });
-        const url = URL.createObjectURL(blob);
-        const a = document.createElement('a');
-        a.href = url;
-        a.download = `export_${Date.now()}.${fmt}`;
-        a.click();
-        URL.revokeObjectURL(url);
+        const localUrl = URL.createObjectURL(blob);
+        const targetFilename = `export_${Date.now()}.${fmt}`;
+        const triggerDownload = (downloadUrl, finalFilename) => {
+          if (window.DAWCommandDispatcher?.isExecutingAI) {
+            showToast(`Xuất nhạc thành công (${fmt.toUpperCase()})!`, "success", "Tải về", () => {
+              const a = document.createElement('a');
+              a.href = downloadUrl;
+              a.download = finalFilename;
+              a.click();
+              if (downloadUrl.startsWith('blob:')) {
+                URL.revokeObjectURL(downloadUrl);
+              }
+            });
+          } else {
+            const a = document.createElement('a');
+            a.href = downloadUrl;
+            a.download = finalFilename;
+            a.click();
+            showToast("Xuất bản âm thanh hoàn tất!", "success");
+            if (downloadUrl.startsWith('blob:')) {
+              URL.revokeObjectURL(downloadUrl);
+            }
+          }
+        };
+        if ((fmt === 'mp3' || fmt === 'ogg') && serverStatus === 'connected') {
+          try {
+            const file = new File([blob], `export_ai.wav`, {
+              type: 'audio/wav'
+            });
+            const formData = new FormData();
+            formData.append('file', file);
+            const uploadResp = await fetch(`${API_AUDIO}/upload`, {
+              method: 'POST',
+              body: formData
+            });
+            if (!uploadResp.ok) throw new Error("Upload failed");
+            const uploadData = await uploadResp.json();
+            const uploadId = uploadData.file_id;
+            const exportResp = await fetch(`${API_AUDIO}/export`, {
+              method: 'POST',
+              headers: {
+                'Content-Type': 'application/json'
+              },
+              body: JSON.stringify({
+                file_id: uploadId,
+                format: fmt,
+                sample_rate: sr,
+                bit_depth: bd
+              })
+            });
+            if (!exportResp.ok) throw new Error("Export failed");
+            const exportData = await exportResp.json();
+            const result = await pollTaskResult(exportData.task_id, 20);
+            if (result.success) {
+              const downloadUrl = `${API_AUDIO}/download/${result.output_file_id}`;
+              triggerDownload(downloadUrl, targetFilename);
+            } else {
+              throw new Error(result.error || 'Server encoding failed');
+            }
+          } catch (transcodeErr) {
+            showToast(`Lỗi chuyển đổi: ${transcodeErr.message}. Tải về dạng WAV thay thế.`, "warning");
+            triggerDownload(localUrl, `export_${Date.now()}.wav`);
+          }
+        } else {
+          const finalFilename = fmt === 'wav' ? `export_${Date.now()}.wav` : `export_${Date.now()}.wav`;
+          if (fmt !== 'wav') {
+            showToast("Đang ngoại tuyến. Tải về định dạng WAV thay thế.", "warning");
+          }
+          triggerDownload(localUrl, finalFilename);
+        }
         return {
           success: true,
           trackId: tid,
@@ -10972,7 +11101,13 @@ const App = () => {
   }, /*#__PURE__*/React.createElement("i", {
     "data-lucide": "bell",
     className: `w-4 h-4 ${toastMessage.type === 'success' ? 'text-emerald-400' : toastMessage.type === 'error' ? 'text-rose-400' : toastMessage.type === 'warning' ? 'text-amber-400' : 'text-cyan-400'}`
-  })), toastMessage.text), /*#__PURE__*/React.createElement(AuthModal, {
+  })), toastMessage.text, toastMessage.onActionClick && /*#__PURE__*/React.createElement("button", {
+    onClick: () => {
+      toastMessage.onActionClick();
+      setToastMessage(null);
+    },
+    className: "ml-2 px-2 py-0.5 bg-purple-700 hover:bg-purple-600 text-white rounded text-[10px] uppercase font-bold"
+  }, toastMessage.actionText || 'Tải về')), /*#__PURE__*/React.createElement(AuthModal, {
     isOpen: authModalOpen,
     mode: authMode,
     forceMandatory: isMandatoryLogin,
diff --git a/app/storage/sonicforge.db b/app/storage/sonicforge.db
index 03dba3f..ea6ca2e 100644
Binary files a/app/storage/sonicforge.db and b/app/storage/sonicforge.db differ