diff --git a/toonz/sources/toonz/convertpopup.cpp b/toonz/sources/toonz/convertpopup.cpp
index 8701f77..175a7be 100644
--- a/toonz/sources/toonz/convertpopup.cpp
+++ b/toonz/sources/toonz/convertpopup.cpp
@@ -256,6 +256,8 @@ void ConvertPopup::Converter::convertLevelWithConvert2Tlv(
     tlvConverter->abort();
   } else {
     int count = tlvConverter->getFramesToConvertCount();
+    popup->m_progressDialog->setMinimum(0);
+    popup->m_progressDialog->setMaximum(count);
     bool stop = false;
     for (int j = 0; j < count && !stop; j++) {
       if (!tlvConverter->convertNext(errorMessage)) {
@@ -263,6 +265,8 @@ void ConvertPopup::Converter::convertLevelWithConvert2Tlv(
         DVGui::warning(QString::fromStdString(errorMessage));
       }
       if (popup->m_progressDialog->wasCanceled()) stop = true;
+
+      popup->m_notifier->notifyFrameCompleted(j);
     }
     if (stop) tlvConverter->abort();
 
@@ -661,9 +665,9 @@ QFrame *ConvertPopup::createTlvSettings() {
   bool ret = true;
   ret      = ret && connect(m_antialias, SIGNAL(currentIndexChanged(int)), this,
                        SLOT(onAntialiasSelected(int)));
-  ret = ret && connect(m_palettePath, SIGNAL(pathChanged()), this,
+  ret      = ret && connect(m_palettePath, SIGNAL(pathChanged()), this,
                        SLOT(onPalettePathChanged()));
-  ret = ret && connect(m_dpiMode, SIGNAL(currentIndexChanged(int)), this,
+  ret      = ret && connect(m_dpiMode, SIGNAL(currentIndexChanged(int)), this,
                        SLOT(onDpiModeSelected(int)));
 
   assert(ret);
@@ -891,7 +895,7 @@ Convert2Tlv *ConvertPopup::makeTlvConverter(const TFilePath &sourceFilePath) {
         sourceFilePath.withParentDir(unpaintedFolder).withName(basename));
   }
   int from = -1, to = -1;
-  if (m_srcFilePaths.size() > 1) {
+  if (m_srcFilePaths.size() == 1) {
     from = m_fromFld->getValue();
     to   = m_toFld->getValue();
   }
@@ -1109,10 +1113,10 @@ void ConvertPopup::getFrameRange(const TFilePath &sourceFilePath,
     TFrameId fid;
     bool ok;
 
-    fid                        = TFrameId(m_fromFld->text().toInt(&ok));
+    fid = TFrameId(m_fromFld->text().toInt(&ok));
     if (ok && fid > from) from = tcrop(fid, firstFrame, lastFrame);
 
-    fid                    = TFrameId(m_toFld->text().toInt(&ok));
+    fid = TFrameId(m_toFld->text().toInt(&ok));
     if (ok && fid < to) to = tcrop(fid, firstFrame, lastFrame);
   }
 }
@@ -1266,9 +1270,9 @@ void ConvertPopup::onOptionsClicked() {
   std::string ext       = m_fileFormat->currentText().toStdString();
   TPropertyGroup *props = getFormatProperties(ext);
 
-  openFormatSettingsPopup(this, ext, props, m_srcFilePaths.size() == 1
-                                                ? m_srcFilePaths[0]
-                                                : TFilePath());
+  openFormatSettingsPopup(
+      this, ext, props,
+      m_srcFilePaths.size() == 1 ? m_srcFilePaths[0] : TFilePath());
 }
 
 //-------------------------------------------------------------------
@@ -1297,9 +1301,8 @@ void ConvertPopup::onPalettePathChanged() {
 bool ConvertPopup::isSaveTlvBackupToNopaintActive() {
   return m_fileFormat->currentText() ==
              TlvExtension /*-- tlvが選択されている --*/
-         &&
-         m_tlvMode->currentText() ==
-             TlvMode_Unpainted /*-- Unpainted Tlvが選択されている --*/
+         && m_tlvMode->currentText() ==
+                TlvMode_Unpainted /*-- Unpainted Tlvが選択されている --*/
          && m_saveBackupToNopaint->isChecked(); /*-- Save Backup to "nopaint"
                                                    Folder オプションが有効 --*/
 }
diff --git a/toonz/sources/toonzlib/convert2tlv.cpp b/toonz/sources/toonzlib/convert2tlv.cpp
index eac4a19..1cb5e21 100644
--- a/toonz/sources/toonzlib/convert2tlv.cpp
+++ b/toonz/sources/toonzlib/convert2tlv.cpp
@@ -55,8 +55,8 @@ inline int distance(const TPixel &c1, const TPixel &c2) {
 
 int findClosest(const std::map<TPixel, int> &colorMap, TPixel &curPixColor) {
   std::map<TPixel, int>::const_iterator it = colorMap.begin();
-  int minDistance = 1000000000;
-  int index       = -1;
+  int minDistance                          = 1000000000;
+  int index                                = -1;
   for (; it != colorMap.end(); ++it) {
     int dist = distance(it->first, curPixColor);
     if (dist < minDistance) {
@@ -140,7 +140,7 @@ int getMaxMatte(const TRaster32P &r) {
   for (int i = 0; i < r->getLy(); i++) {
     TPixel32 *pix = r->pixels(i);
     for (int j = 0; j < r->getLx(); j++, pix++) {
-      maxMatte                     = std::max(maxMatte, (int)pix->m);
+      maxMatte = std::max(maxMatte, (int)pix->m);
       if (pix->m != 255) withMatte = true;
     }
   }
@@ -178,7 +178,7 @@ int getFramesCount(const TLevelP &l, int from, int to) {
   while (it != l->end() && it->first.getNumber() <= to) it++, count++;
   return count;
 }
-}
+}  // namespace
 // namespace
 
 std::map<TPixel, int>::const_iterator Convert2Tlv::findNearestColor(
@@ -186,7 +186,7 @@ std::map<TPixel, int>::const_iterator Convert2Tlv::findNearestColor(
   // assert((int)colorMap.size()>toIndex);
   // assert((int)colorMap.size()>fromIndex);
   std::map<TPixel, int>::const_iterator ret = m_colorMap.end(),
-                                        it = m_colorMap.begin();
+                                        it  = m_colorMap.begin();
   // std::advance(it, fromIndex);
 
   int mindist = 1000;
@@ -337,7 +337,7 @@ void Convert2Tlv::buildInksForNAAImage(TRasterCM32P &rout,
         curColor = *pixin;
         if ((it = m_colorMap.find(curColor)) == m_colorMap.end()) {
           if (m_lastIndex < 4095) m_colorMap[curColor] = ++m_lastIndex;
-          curIndex                                     = m_lastIndex;
+          curIndex = m_lastIndex;
         } else
           curIndex = it->second;
       }
@@ -510,6 +510,8 @@ void Convert2Tlv::buildToonzRaster(TRasterCM32P &rout, const TRasterP &rin1,
     int maxMatte = getMaxMatte((TRaster32P)rU);
     if (maxMatte == -1)
       buildInksFromGrayTones(r, rU);
+    else if (maxMatte == 0)  // empty frame doesn't need further computation
+      return;
     else {
       if (maxMatte < 255) normalize(rU, maxMatte);
       buildInks(r, (TRaster32P)rU /*rP,*/);
@@ -538,7 +540,7 @@ void Convert2Tlv::buildToonzRaster(TRasterCM32P &rout, const TRasterP &rin1,
 
 TPalette *Convert2Tlv::buildPalette() {
   std::map<TPixel, int>::const_iterator it = m_colorMap.begin();
-  TPalette::Page *page = m_palette->getPage(0);
+  TPalette::Page *page                     = m_palette->getPage(0);
 
   QList<int> stylesToBeAddedToPage;
 
@@ -709,7 +711,7 @@ bool Convert2Tlv::init(std::string &errorMessage) {
   m_colorMap.clear();
 
   try {
-    m_lr1               = TLevelReaderP(m_levelIn1);
+    m_lr1 = TLevelReaderP(m_levelIn1);
     if (m_lr1) m_level1 = m_lr1->loadInfo();
   } catch (...) {
     errorMessage =
@@ -727,7 +729,7 @@ bool Convert2Tlv::init(std::string &errorMessage) {
 
   if (m_levelIn2 != TFilePath()) {
     try {
-      m_lr2             = TLevelReaderP(m_levelIn2);
+      m_lr2 = TLevelReaderP(m_levelIn2);
       if (m_lr2) level2 = m_lr2->loadInfo();
     } catch (...) {
       errorMessage =
@@ -815,7 +817,7 @@ bool Convert2Tlv::init(std::string &errorMessage) {
     for (int i = 0; i < m_palette->getStyleCount(); i++)
       if (m_palette->getStylePage(i)) {
         m_colorMap[m_palette->getStyle(i)->getMainColor()] = i;
-        if (i > m_lastIndex) m_lastIndex                   = i;
+        if (i > m_lastIndex) m_lastIndex = i;
       }
     assert(m_colorMap.size() == m_palette->getStyleInPagesCount());
   }
@@ -898,7 +900,9 @@ bool Convert2Tlv::convertNext(std::string &errorMessage) {
 
   TLevel::Iterator itaux = m_it;
   itaux++;
-  if (itaux == m_level1->end())  // ultimo frame da scrivere.
+  if (itaux == m_level1->end() ||
+      (m_to != -1 &&
+       itaux->first.getNumber() > m_to))  // ultimo frame da scrivere.
     timg->setPalette(buildPalette());
 
   iw->save(timg);