diff --git a/assets/js/creations/file.js b/assets/js/creations/file.js
index b4cd2f78..f4cd9354 100755
--- a/assets/js/creations/file.js
+++ b/assets/js/creations/file.js
@@ -867,13 +867,13 @@ function createTrackXml(track) {
 }
 
 async function modifyAndSaveExistingMmp() {
-  const content = generateXmlFromState();
-  downloadFile(content, "projeto_editado.mmp");
+  console.log("EXPORT MMPZ");
+  await generateAndDownloadMmpz("projeto_editado");
 }
 
 async function generateNewMmp() {
-  const content = generateXmlFromState();
-  downloadFile(content, "novo_projeto.mmp");
+  console.log("EXPORT MMPZ");
+  await generateAndDownloadMmpz("novo_projeto");
 }
 
 function downloadFile(content, fileName) {
@@ -891,22 +891,17 @@ function downloadFile(content, fileName) {
 async function generateAndDownloadMmpz(baseName) {
   initializeAudioContext();
 
-  // 1) gera XML base (patterns OK) — hoje isso já funciona no seu projeto
-  const baseXmlString = generateXmlFromState(); // já inclui applyPlaylistClipsToXml :contentReference[oaicite:3]{index=3}
+  const baseXmlString = generateXmlFromState(); // seu método atual (patterns OK)
   const xmlDoc = new DOMParser().parseFromString(baseXmlString, "application/xml");
 
-  // 2) cria zip e injeta samples sliceados + reescreve sampletracks/sampletco
-  // eslint-disable-next-line no-undef
+  // JSZip precisa existir (você já usa pra abrir mmpz)
   const zip = new JSZip();
 
   await applySampleTracksToXmlAndZip(xmlDoc, zip);
 
-  // 3) grava o .mmp dentro do zip
   const finalXml = new XMLSerializer().serializeToString(xmlDoc);
-  const mmpName = `${baseName}.mmp`;
-  zip.file(mmpName, finalXml);
+  zip.file(`${baseName}.mmp`, finalXml);
 
-  // 4) baixa .mmpz
   const blob = await zip.generateAsync({ type: "blob", compression: "DEFLATE" });
   downloadBlob(blob, `${baseName}.mmpz`);
 }
@@ -922,17 +917,19 @@ function downloadBlob(blob, fileName) {
   URL.revokeObjectURL(url);
 }
 
-// -------------------- WAV helpers --------------------
-
-function _sanitizeFileName(name) {
-  return String(name || "clip")
-    .normalize("NFKD")
-    .replace(/[^\w\-\.]+/g, "_")
-    .replace(/_+/g, "_")
-    .replace(/^_+|_+$/g, "")
-    .slice(0, 80) || "clip";
+function downloadBlob(blob, fileName) {
+  const url = URL.createObjectURL(blob);
+  const a = document.createElement("a");
+  a.href = url;
+  a.download = fileName;
+  document.body.appendChild(a);
+  a.click();
+  document.body.removeChild(a);
+  URL.revokeObjectURL(url);
 }
 
+// -------------------- WAV helpers --------------------
+
 function _clamp(n, a, b) {
   const x = Number(n);
   if (!Number.isFinite(x)) return a;
@@ -959,13 +956,13 @@ function _encodeWav16(channelData, sampleRate) {
   view.setUint32(4, 36 + dataSize, true);
   writeStr(8, "WAVE");
   writeStr(12, "fmt ");
-  view.setUint32(16, 16, true);            // PCM
-  view.setUint16(20, 1, true);             // format = 1
+  view.setUint32(16, 16, true);
+  view.setUint16(20, 1, true);
   view.setUint16(22, numChannels, true);
   view.setUint32(24, sampleRate, true);
   view.setUint32(28, byteRate, true);
   view.setUint16(32, blockAlign, true);
-  view.setUint16(34, 16, true);            // bits
+  view.setUint16(34, 16, true);
   writeStr(36, "data");
   view.setUint32(40, dataSize, true);
 
@@ -978,7 +975,6 @@ function _encodeWav16(channelData, sampleRate) {
       offset += 2;
     }
   }
-
   return buffer;
 }
 
@@ -998,10 +994,7 @@ function _sliceToWavArrayBuffer(audioBuffer, offsetSec, durSec, { volume = 1, pa
   const gR = Math.sin(angle) * volume;
 
   const inCh = audioBuffer.numberOfChannels || 1;
-
-  // se for mono e pan != 0, gera estéreo pra “congelar” a pan
   const outCh = (inCh === 1 && Math.abs(pan) > 1e-6) ? 2 : inCh;
-
   const out = new Array(outCh).fill(0).map(() => new Float32Array(sliceLen));
 
   if (inCh === 1) {
@@ -1014,23 +1007,32 @@ function _sliceToWavArrayBuffer(audioBuffer, offsetSec, durSec, { volume = 1, pa
         out[1][i] = src[i] * gR;
       }
     }
-  } else if (inCh >= 2) {
+  } else {
     const L = audioBuffer.getChannelData(0).subarray(start, end);
     const R = audioBuffer.getChannelData(1).subarray(start, end);
     for (let i = 0; i < sliceLen; i++) {
       out[0][i] = L[i] * gL;
       out[1][i] = R[i] * gR;
     }
-    // se tiver mais canais, copia/atenua sem pan (raro)
-    for (let ch = 2; ch < outCh; ch++) {
-      const C = audioBuffer.getChannelData(ch).subarray(start, end);
-      for (let i = 0; i < sliceLen; i++) out[ch][i] = C[i] * volume;
-    }
   }
 
   return _encodeWav16(out, sr);
 }
 
+function _makeSilenceWav(sampleRate = 44100, seconds = 0.1) {
+  const len = Math.max(1, Math.floor(sampleRate * seconds));
+  const ch = [new Float32Array(len)];
+  return _encodeWav16(ch, sampleRate);
+}
+
+function _ensureSilenceInZip(zip) {
+  if (__exportCache.silencePath) return __exportCache.silencePath;
+  const path = "samples/__silence.wav";
+  zip.file(path, _makeSilenceWav(44100, 0.1));
+  __exportCache.silencePath = path;
+  return path;
+}
+
 async function _ensureClipBuffer(clip) {
   if (clip?.buffer) return clip.buffer;
 
@@ -1047,24 +1049,74 @@ async function _ensureClipBuffer(clip) {
   return decoded;
 }
 
+const __exportCache = {
+  decodedBySrc: new Map(),   // src -> AudioBuffer
+  rawBySrc: new Map(),       // src -> ArrayBuffer (wav original)
+  sliceByKey: new Map(),     // key -> { path }
+  silencePath: null,
+};
+
+function _resetExportCache() {
+  __exportCache.decodedBySrc.clear();
+  __exportCache.rawBySrc.clear();
+  __exportCache.sliceByKey.clear();
+  __exportCache.silencePath = null;
+}
+
+function _sanitizeFileName(name) {
+  return String(name || "clip")
+    .normalize("NFKD")
+    .replace(/[^\w\-\.]+/g, "_")
+    .replace(/_+/g, "_")
+    .replace(/^_+|_+$/g, "")
+    .slice(0, 80) || "clip";
+}
+
+function _clamp(n, a, b) {
+  const x = Number(n);
+  if (!Number.isFinite(x)) return a;
+  return Math.max(a, Math.min(b, x));
+}
+
+async function _fetchArrayBufferCached(url) {
+  if (__exportCache.rawBySrc.has(url)) return __exportCache.rawBySrc.get(url);
+  const res = await fetch(url);
+  if (!res.ok) throw new Error(`Falha ao buscar áudio: ${url}`);
+  const arr = await res.arrayBuffer();
+  __exportCache.rawBySrc.set(url, arr);
+  return arr;
+}
+
+async function _decodeAudioBufferCached(url) {
+  if (__exportCache.decodedBySrc.has(url)) return __exportCache.decodedBySrc.get(url);
+  const ctx = getAudioContext();
+  const arr = await _fetchArrayBufferCached(url);
+  const decoded = await ctx.decodeAudioData(arr.slice(0));
+  __exportCache.decodedBySrc.set(url, decoded);
+  return decoded;
+}
+
 // -------------------- XML: SampleTracks + zip --------------------
 
 async function applySampleTracksToXmlAndZip(xmlDoc, zip) {
+  _resetExportCache();
+
   const songTc = xmlDoc.querySelector("song > trackcontainer");
   if (!songTc) return;
 
-  // sampletracks no LMMS são track[type="2"] e cada clipe é <sampletco> :contentReference[oaicite:4]{index=4}
+  // template se existir
   const existingSample = songTc.querySelector(':scope > track[type="2"]');
   const template = existingSample ? existingSample.cloneNode(true) : null;
 
-  // remove todas as sample tracks existentes e recria pelo estado atual
+  // remove todas as sample tracks antigas
   Array.from(songTc.querySelectorAll(':scope > track[type="2"]')).forEach(n => n.remove());
 
   const secondsPerStep = getSecondsPerStep();
+
   const tracks = appState.audio?.tracks || [];
   const clips = appState.audio?.clips || [];
 
-  // recria track por lane
+  // agrupa clips por lane
   for (let i = 0; i < tracks.length; i++) {
     const lane = tracks[i];
     const laneName = lane?.name || `Áudio ${i + 1}`;
@@ -1084,7 +1136,7 @@ async function applySampleTracksToXmlAndZip(xmlDoc, zip) {
     trackNode.setAttribute("type", "2");
     trackNode.setAttribute("name", laneName);
 
-    // garante sampletrack com vol/pan neutro (vamos “bakar” no WAV por clipe)
+    // sampletrack neutro (mix “baked” no wav)
     let st = trackNode.querySelector("sampletrack");
     if (!st) {
       st = xmlDoc.createElement("sampletrack");
@@ -1093,7 +1145,6 @@ async function applySampleTracksToXmlAndZip(xmlDoc, zip) {
     st.setAttribute("vol", "100");
     st.setAttribute("pan", "0");
 
-    // limpa sampletco anteriores
     Array.from(trackNode.querySelectorAll(":scope > sampletco")).forEach(n => n.remove());
 
     const laneClips = clips
@@ -1104,36 +1155,97 @@ async function applySampleTracksToXmlAndZip(xmlDoc, zip) {
     for (let cidx = 0; cidx < laneClips.length; cidx++) {
       const clip = laneClips[cidx];
 
-      const buffer = await _ensureClipBuffer(clip);
-      if (!buffer) continue;
-
-      const offsetSec = clip.offset || 0;
+      const startSec = clip.startTimeInSeconds || 0;
       const durSec = clip.durationInSeconds || 0;
       if (durSec <= 0.0001) continue;
 
-      const wav = _sliceToWavArrayBuffer(buffer, offsetSec, durSec, {
-        volume: clip.volume ?? 1,
-        pan: clip.pan ?? 0,
-      });
+      const vol = clip.volume ?? 1;
+      const pan = clip.pan ?? 0;
+      const muted = !!clip.muted || vol === 0;
+
+      const posTicks = Math.round((startSec / secondsPerStep) * 12);
+      const lenTicks = Math.max(1, Math.round((durSec / secondsPerStep) * 12));
+
+      // -----------------------------------------
+      // ✅ OTIMIZAÇÃO 1: mutado -> usa silence.wav
+      // -----------------------------------------
+      if (muted) {
+        const silPath = _ensureSilenceInZip(zip);
+        const tco = xmlDoc.createElement("sampletco");
+        tco.setAttribute("pos", String(Math.max(0, posTicks)));
+        tco.setAttribute("len", String(lenTicks));
+        tco.setAttribute("muted", "0"); // já é silêncio
+        tco.setAttribute("src", silPath);
+        trackNode.appendChild(tco);
+        continue;
+      }
+
+      // precisamos do sourcePath (arquivo original)
+      const srcUrl = clip.sourcePath || clip.src || clip.url;
+      if (!srcUrl) continue;
+
+      const offsetSec = clip.offset || 0;
+
+      // -----------------------------------------
+      // ✅ OTIMIZAÇÃO 2: sem offset + sem bake mix
+      // -> usa arquivo original no zip (sem decode/encode)
+      // -----------------------------------------
+      const needsOffset = Math.abs(offsetSec) > 1e-6;
+      const needsBake = Math.abs((vol ?? 1) - 1) > 1e-6 || Math.abs((pan ?? 0) - 0) > 1e-6;
+
+      if (!needsOffset && !needsBake) {
+        const raw = await _fetchArrayBufferCached(srcUrl);
+        const name =
+          `${_sanitizeFileName(laneName)}__${_sanitizeFileName(clip.name || "clip")}` +
+          `__raw__${_sanitizeFileName(clip.id || String(cidx))}.wav`;
+        const zipPath = `samples/${name}`;
+
+        // evita regravar o mesmo raw várias vezes
+        if (!zip.file(zipPath)) zip.file(zipPath, raw);
+
+        const tco = xmlDoc.createElement("sampletco");
+        tco.setAttribute("pos", String(Math.max(0, posTicks)));
+        tco.setAttribute("len", String(lenTicks));
+        tco.setAttribute("muted", "0");
+        tco.setAttribute("src", zipPath);
+        trackNode.appendChild(tco);
+        continue;
+      }
+
+      // -----------------------------------------
+      // ✅ OTIMIZAÇÃO 3: cache de slice idêntico
+      // -----------------------------------------
+      const sliceKey = `${srcUrl}__o=${offsetSec.toFixed(6)}__d=${durSec.toFixed(6)}__v=${Number(vol).toFixed(6)}__p=${Number(pan).toFixed(6)}`;
+      const cached = __exportCache.sliceByKey.get(sliceKey);
+      if (cached) {
+        const tco = xmlDoc.createElement("sampletco");
+        tco.setAttribute("pos", String(Math.max(0, posTicks)));
+        tco.setAttribute("len", String(lenTicks));
+        tco.setAttribute("muted", "0");
+        tco.setAttribute("src", cached.path);
+        trackNode.appendChild(tco);
+        continue;
+      }
+
+      // decode uma vez por srcUrl
+      const buffer = await _decodeAudioBufferCached(srcUrl);
+
+      const wav = _sliceToWavArrayBuffer(buffer, offsetSec, durSec, { volume: vol, pan });
       if (!wav) continue;
 
       const sliceName =
         `${_sanitizeFileName(laneName)}__${_sanitizeFileName(clip.name || "clip")}` +
-        `__${_sanitizeFileName(clip.id || String(cidx))}.wav`;
-
+        `__slice__${_sanitizeFileName(clip.id || String(cidx))}.wav`;
       const zipPath = `samples/${sliceName}`;
-      zip.file(zipPath, wav);
 
-      // converte segundos -> ticks LMMS (12 ticks por step), inverso do seu parser :contentReference[oaicite:5]{index=5}
-      const posTicks = Math.round(((clip.startTimeInSeconds || 0) / secondsPerStep) * 12);
-      const lenTicks = Math.max(1, Math.round((durSec / secondsPerStep) * 12));
+      zip.file(zipPath, wav);
+      __exportCache.sliceByKey.set(sliceKey, { path: zipPath });
 
       const tco = xmlDoc.createElement("sampletco");
       tco.setAttribute("pos", String(Math.max(0, posTicks)));
       tco.setAttribute("len", String(lenTicks));
-      tco.setAttribute("muted", String((clip.volume === 0 || clip.muted) ? 1 : 0));
+      tco.setAttribute("muted", "0");
       tco.setAttribute("src", zipPath);
-
       trackNode.appendChild(tco);
     }
 
@@ -1141,4 +1253,5 @@ async function applySampleTracksToXmlAndZip(xmlDoc, zip) {
   }
 }
 
+
 export { generateXmlFromState as generateXmlFromStateExported };
\ No newline at end of file