diff --git a/CMakeLists.txt b/CMakeLists.txt
index decea3fef..581e1c2de 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -789,6 +789,7 @@ src/gui/channels.cpp
 src/gui/chanOsc.cpp
 src/gui/clock.cpp
 src/gui/compatFlags.cpp
+src/gui/csPlayer.cpp
 src/gui/cursor.cpp
 src/gui/dataList.cpp
 src/gui/debugWindow.cpp
diff --git a/src/engine/cmdStream.cpp b/src/engine/cmdStream.cpp
index 6036364c5..329f9a798 100644
--- a/src/engine/cmdStream.cpp
+++ b/src/engine/cmdStream.cpp
@@ -35,8 +35,30 @@ bool DivCSChannelState::doCall(unsigned int addr) {
   return true;
 }
 
+unsigned char* DivCSPlayer::getData() {
+  return b;
+}
+
+size_t DivCSPlayer::getDataLen() {
+  return bLen;
+}
+
+DivCSChannelState* DivCSPlayer::getChanState(int ch) {
+  return &chan[ch];
+}
+
+unsigned char* DivCSPlayer::getFastDelays() {
+  return fastDelays;
+}
+
+unsigned char* DivCSPlayer::getFastCmds() {
+  return fastCmds;
+}
+
 void DivCSPlayer::cleanup() {
   delete b;
+  b=NULL;
+  bLen=0;
 }
 
 bool DivCSPlayer::tick() {
@@ -383,7 +405,8 @@ bool DivCSPlayer::init() {
       stream.readI();
       continue;
     }
-    chan[i].readPos=stream.readI();
+    chan[i].startPos=stream.readI();
+    chan[i].readPos=chan[i].startPos;
   }
 
   stream.read(fastDelays,16);
@@ -427,3 +450,17 @@ bool DivEngine::playStream(unsigned char* f, size_t length) {
   BUSY_END;
   return true;
 }
+
+DivCSPlayer* DivEngine::getStreamPlayer() {
+  return cmdStreamInt;
+}
+
+bool DivEngine::killStream() {
+  if (!cmdStreamInt) return false;
+  BUSY_BEGIN;
+  cmdStreamInt->cleanup();
+  delete cmdStreamInt;
+  cmdStreamInt=NULL;
+  BUSY_END;
+  return true;
+}
diff --git a/src/engine/cmdStream.h b/src/engine/cmdStream.h
index cd0a786b7..8ecc17c67 100644
--- a/src/engine/cmdStream.h
+++ b/src/engine/cmdStream.h
@@ -26,6 +26,7 @@
 class DivEngine;
 
 struct DivCSChannelState {
+  unsigned int startPos;
   unsigned int readPos;
   int waitTicks;
 
@@ -69,6 +70,7 @@ struct DivCSChannelState {
 class DivCSPlayer {
   DivEngine* e;
   unsigned char* b;
+  size_t bLen;
   SafeReader stream;
   DivCSChannelState chan[DIV_MAX_CHANS];
   unsigned char fastDelays[16];
@@ -77,12 +79,18 @@ class DivCSPlayer {
 
   short vibTable[64];
   public:
+    unsigned char* getData();
+    size_t getDataLen();
+    DivCSChannelState* getChanState(int ch);
+    unsigned char* getFastDelays();
+    unsigned char* getFastCmds();
     void cleanup();
     bool tick();
     bool init();
     DivCSPlayer(DivEngine* en, unsigned char* buf, size_t len):
       e(en),
       b(buf),
+      bLen(len),
       stream(buf,len) {}
 };
 
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 8e3bacdf2..049cce820 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -633,6 +633,10 @@ class DivEngine {
     bool load(unsigned char* f, size_t length);
     // play a binary command stream.
     bool playStream(unsigned char* f, size_t length);
+    // get the playing stream.
+    DivCSPlayer* getStreamPlayer();
+    // destroy command stream player.
+    bool killStream();
     // save as .dmf.
     SafeWriter* saveDMF(unsigned char version);
     // save as .fur.
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index aab72623f..bc62d2221 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1595,9 +1595,7 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
 
   if (subticks==tickMult && cmdStreamInt) {
     if (!cmdStreamInt->tick()) {
-      cmdStreamInt->cleanup();
-      delete cmdStreamInt;
-      cmdStreamInt=NULL;
+      // !!!
     }
   }
 
diff --git a/src/engine/safeWriter.cpp b/src/engine/safeWriter.cpp
index 0e447b2dc..c2388c460 100644
--- a/src/engine/safeWriter.cpp
+++ b/src/engine/safeWriter.cpp
@@ -227,3 +227,9 @@ void SafeWriter::finish() {
   buf=NULL;
   operative=false;
 }
+
+void SafeWriter::disown() {
+  if (!operative) return;
+  buf=NULL;
+  operative=false;
+}
diff --git a/src/engine/safeWriter.h b/src/engine/safeWriter.h
index 640e78c47..666b0f1e2 100644
--- a/src/engine/safeWriter.h
+++ b/src/engine/safeWriter.h
@@ -62,6 +62,7 @@ class SafeWriter {
     void init();
     SafeReader* toReader();
     void finish();
+    void disown();
 
     SafeWriter():
       operative(false),
diff --git a/src/gui/csPlayer.cpp b/src/gui/csPlayer.cpp
new file mode 100644
index 000000000..cec9ec2c0
--- /dev/null
+++ b/src/gui/csPlayer.cpp
@@ -0,0 +1,185 @@
+/**
+ * Furnace Tracker - multi-system chiptune tracker
+ * Copyright (C) 2021-2024 tildearrow and contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "gui.h"
+#include <fmt/printf.h>
+#include "imgui.h"
+
+void FurnaceGUI::drawCSPlayer() {
+  if (nextWindow==GUI_WINDOW_CS_PLAYER) {
+    csPlayerOpen=true;
+    ImGui::SetNextWindowFocus();
+    nextWindow=GUI_WINDOW_NOTHING;
+  }
+  if (!csPlayerOpen) return;
+  if (ImGui::Begin("Command Stream Player",&csPlayerOpen,globalWinFlags)) {
+    if (ImGui::Button("Load")) {
+      openFileDialog(GUI_FILE_CMDSTREAM_OPEN);
+    }
+    ImGui::SameLine();
+    if (ImGui::Button("Kill")) {
+      if (!e->killStream()) {
+        showError("Kikai wa mou shindeiru!");
+      }
+    }
+    ImGui::SameLine();
+    if (ImGui::Button("Burn Current Song")) {
+      SafeWriter* w=e->saveCommand(true);
+      if (w!=NULL) {
+        if (!e->playStream(w->getFinalBuf(),w->size())) {
+          showError(e->getLastError());
+          w->finish();
+          delete w;
+        } else {
+          w->disown();
+          delete w;
+        }
+      }
+    }
+
+    DivCSPlayer* cs=e->getStreamPlayer();
+    if (cs) {
+      if (ImGui::BeginTabBar("CSOptions")) {
+        int chans=e->getTotalChannelCount();
+        if (ImGui::BeginTabItem("Status")) {
+          ImGui::EndTabItem();
+        }
+        if (ImGui::BeginTabItem("Hex")) {
+          ImGui::PushFont(patFont);
+          if (ImGui::BeginTable("CSHexPos",chans,ImGuiTableFlags_SizingStretchSame)) {
+            ImGui::TableNextRow();
+            for (int i=0; i<chans; i++) {
+              ImGui::TableNextColumn();
+              ImGui::Text("%d",i);
+            }
+            ImGui::TableNextRow();
+            for (int i=0; i<chans; i++) {
+              DivCSChannelState* state=cs->getChanState(i);
+              ImGui::TableNextColumn();
+              ImGui::Text("$%x",state->readPos);
+            }
+            ImGui::EndTable();
+          }
+
+          float oneCharSize=ImGui::CalcTextSize("A").x;
+          float threeCharSize=ImGui::CalcTextSize("AA").x;
+          float charViewSize=ImGui::CalcTextSize("0123456789ABCDEF").x;
+
+          if (ImGui::BeginTable("CSHexPos",19)) {
+            char charView[17];
+            ImGui::TableSetupScrollFreeze(1,1);
+            ImGui::TableSetupColumn("addr",ImGuiTableColumnFlags_WidthFixed);
+            ImGui::TableSetupColumn("d0",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d1",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d2",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d3",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d4",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d5",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d6",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d7",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d8",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d9",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d10",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d11",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d12",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d13",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d14",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("d15",ImGuiTableColumnFlags_WidthFixed,threeCharSize);
+            ImGui::TableSetupColumn("spacer",ImGuiTableColumnFlags_WidthFixed,oneCharSize);
+            ImGui::TableSetupColumn("char",ImGuiTableColumnFlags_WidthFixed,charViewSize);
+
+            // header
+            ImGui::TableNextRow();
+            ImGui::TableNextColumn();
+            for (int i=0; i<16; i++) {
+              ImGui::TableNextColumn();
+              ImGui::Text("%X",i);
+            }
+
+            // content
+            unsigned char* buf=cs->getData();
+            size_t bufSize=cs->getDataLen();
+            csClipper.Begin((bufSize+15)>>4,ImGui::GetTextLineHeightWithSpacing());
+            while (csClipper.Step()) {
+              //std::vector<int> highlightsUnsorted;
+              std::vector<int> highlights;
+              int nextHighlight=-1;
+              int highlightPos=0;
+
+              for (int i=0; i<chans; i++) {
+                DivCSChannelState* state=cs->getChanState(i);
+                if ((int)state->readPos>=(csClipper.DisplayStart<<4) && (int)state->readPos<=(csClipper.DisplayEnd<<4)) {
+                  highlights.push_back(state->readPos);
+                }
+              }
+              if (!highlights.empty()) nextHighlight=highlights[0];
+
+
+              for (int i=csClipper.DisplayStart; i<csClipper.DisplayEnd; i++) {
+                ImGui::TableNextRow();
+                ImGui::TableNextColumn();
+                ImGui::Text("%.4X",i<<4);
+
+                for (int j=0; j<16; j++) {
+                  int pos=(i<<4)|j;
+                  ImGui::TableNextColumn();
+                  if (pos>=(int)bufSize) continue;
+                  if (pos==nextHighlight) {
+                    ImGui::TableSetBgColor(ImGuiTableBgTarget_CellBg,ImGui::GetColorU32(ImGuiCol_Header));
+                    highlightPos++;
+                    if (highlightPos>=(int)highlights.size()) {
+                      nextHighlight=-1;
+                    } else {
+                      nextHighlight=highlights[highlightPos];
+                    }
+                  }
+                  ImGui::Text("%.2X",buf[pos]);
+                }
+
+                ImGui::TableNextColumn();
+                ImGui::TableNextColumn();
+                for (int j=0; j<16; j++) {
+                  int pos=(i<<4)|j;
+                  if (pos>=(int)bufSize) {
+                    charView[j]=' ';
+                  } else if (buf[pos]>=0x20 && buf[pos]<=0x7e) {
+                    charView[j]=buf[pos];
+                  } else {
+                    charView[j]='.';
+                  }
+                }
+                charView[16]=0;
+
+                ImGui::TextUnformatted(charView);
+              }
+            }
+            csClipper.End();
+
+            ImGui::EndTable();
+          }
+          ImGui::PopFont();
+          ImGui::EndTabItem();
+        }
+        ImGui::EndTabBar();
+      }
+    }
+  }
+  if (ImGui::IsWindowFocused(ImGuiFocusedFlags_ChildWindows)) curWindow=GUI_WINDOW_CS_PLAYER;
+  ImGui::End();
+}
diff --git a/src/gui/debugWindow.cpp b/src/gui/debugWindow.cpp
index 98a2d9dc7..ed5057915 100644
--- a/src/gui/debugWindow.cpp
+++ b/src/gui/debugWindow.cpp
@@ -77,7 +77,7 @@ void FurnaceGUI::drawDebug() {
       ImGui::SameLine();
       if (ImGui::Button("Pattern Advance")) e->haltWhen(DIV_HALT_PATTERN);
 
-      if (ImGui::Button("Play Command Stream")) openFileDialog(GUI_FILE_CMDSTREAM_OPEN);
+      if (ImGui::Button("Play Command Stream")) nextWindow=GUI_WINDOW_CS_PLAYER;
 
       if (ImGui::Button("Panic")) e->syncReset();
       ImGui::SameLine();
diff --git a/src/gui/doAction.cpp b/src/gui/doAction.cpp
index c706410b3..fe0adc775 100644
--- a/src/gui/doAction.cpp
+++ b/src/gui/doAction.cpp
@@ -316,6 +316,9 @@ void FurnaceGUI::doAction(int what) {
     case GUI_ACTION_WINDOW_MEMORY:
       nextWindow=GUI_WINDOW_MEMORY;
       break;
+    case GUI_ACTION_WINDOW_CS_PLAYER:
+      nextWindow=GUI_WINDOW_CS_PLAYER;
+      break;
     
     case GUI_ACTION_COLLAPSE_WINDOW:
       collapseWindow=true;
@@ -418,6 +421,9 @@ void FurnaceGUI::doAction(int what) {
         case GUI_WINDOW_MEMORY:
           memoryOpen=false;
           break;
+        case GUI_WINDOW_CS_PLAYER:
+          csPlayerOpen=false;
+          break;
         default:
           break;
       }
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index c9593d7c1..ed0d437e3 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -3463,6 +3463,7 @@ bool FurnaceGUI::loop() {
   DECLARE_METRIC(volMeter)
   DECLARE_METRIC(settings)
   DECLARE_METRIC(debug)
+  DECLARE_METRIC(csPlayer)
   DECLARE_METRIC(stats)
   DECLARE_METRIC(memory)
   DECLARE_METRIC(compatFlags)
@@ -4046,6 +4047,7 @@ bool FurnaceGUI::loop() {
         IMPORT_CLOSE(groovesOpen);
         IMPORT_CLOSE(xyOscOpen);
         IMPORT_CLOSE(memoryOpen);
+        IMPORT_CLOSE(csPlayerOpen);
       } else if (pendingLayoutImportStep==1) {
         // let the UI settle
       } else if (pendingLayoutImportStep==2) {
@@ -4629,6 +4631,7 @@ bool FurnaceGUI::loop() {
       globalWinFlags=0;
       MEASURE(settings,drawSettings());
       MEASURE(debug,drawDebug());
+      MEASURE(csPlayer,drawCSPlayer());
       MEASURE(log,drawLog());
       MEASURE(compatFlags,drawCompatFlags());
       MEASURE(stats,drawStats());
@@ -4669,6 +4672,7 @@ bool FurnaceGUI::loop() {
       MEASURE(volMeter,drawVolMeter());
       MEASURE(settings,drawSettings());
       MEASURE(debug,drawDebug());
+      MEASURE(csPlayer,drawCSPlayer());
       MEASURE(stats,drawStats());
       MEASURE(memory,drawMemory());
       MEASURE(compatFlags,drawCompatFlags());
@@ -7495,6 +7499,7 @@ FurnaceGUI::FurnaceGUI():
   groovesOpen(false),
   xyOscOpen(false),
   memoryOpen(false),
+  csPlayerOpen(false),
   shortIntro(false),
   insListDir(false),
   waveListDir(false),
diff --git a/src/gui/gui.h b/src/gui/gui.h
index 1b036bae5..3b1a2b552 100644
--- a/src/gui/gui.h
+++ b/src/gui/gui.h
@@ -478,6 +478,7 @@ enum FurnaceGUIWindows {
   GUI_WINDOW_XY_OSC,
   GUI_WINDOW_INTRO_MON,
   GUI_WINDOW_MEMORY,
+  GUI_WINDOW_CS_PLAYER,
   GUI_WINDOW_SPOILER
 };
 
@@ -669,6 +670,7 @@ enum FurnaceGUIActions {
   GUI_ACTION_WINDOW_GROOVES,
   GUI_ACTION_WINDOW_XY_OSC,
   GUI_ACTION_WINDOW_MEMORY,
+  GUI_ACTION_WINDOW_CS_PLAYER,
 
   GUI_ACTION_COLLAPSE_WINDOW,
   GUI_ACTION_CLOSE_WINDOW,
@@ -2064,7 +2066,7 @@ class FurnaceGUI {
   bool mixerOpen, debugOpen, inspectorOpen, oscOpen, volMeterOpen, statsOpen, compatFlagsOpen;
   bool pianoOpen, notesOpen, channelsOpen, regViewOpen, logOpen, effectListOpen, chanOscOpen;
   bool subSongsOpen, findOpen, spoilerOpen, patManagerOpen, sysManagerOpen, clockOpen, speedOpen;
-  bool groovesOpen, xyOscOpen, memoryOpen;
+  bool groovesOpen, xyOscOpen, memoryOpen, csPlayerOpen;
 
   bool shortIntro;
   bool insListDir, waveListDir, sampleListDir;
@@ -2449,6 +2451,9 @@ class FurnaceGUI {
   // tutorial
   int curTutorial, curTutorialStep;
 
+  // command stream player
+  ImGuiListClipper csClipper;
+
   // export options
   int audioExportType;
   FurnaceGUIExportTypes curExportType;
@@ -2573,6 +2578,7 @@ class FurnaceGUI {
   void drawIntro(double introTime, bool monitor=false);
   void drawSettings();
   void drawDebug();
+  void drawCSPlayer();
   void drawNewSong();
   void drawPalette();
   void drawExport();
diff --git a/src/gui/guiConst.cpp b/src/gui/guiConst.cpp
index b17688032..fc4916229 100644
--- a/src/gui/guiConst.cpp
+++ b/src/gui/guiConst.cpp
@@ -606,6 +606,7 @@ const FurnaceGUIActionDef guiActions[GUI_ACTION_MAX]={
   D("WINDOW_GROOVES", "Grooves", 0),
   D("WINDOW_XY_OSC", "Oscilloscope (X-Y)", 0),
   D("WINDOW_MEMORY", "Memory Compositiom", 0),
+  D("WINDOW_CS_PLAYER", "Command Stream Player", 0),
 
   D("COLLAPSE_WINDOW", "Collapse/expand current window", 0),
   D("CLOSE_WINDOW", "Close current window", FURKMOD_SHIFT|SDLK_ESCAPE),
diff --git a/src/gui/settings.cpp b/src/gui/settings.cpp
index 283862ee2..f19dc9d04 100644
--- a/src/gui/settings.cpp
+++ b/src/gui/settings.cpp
@@ -1759,6 +1759,7 @@ void FurnaceGUI::drawSettings() {
           UI_KEYBIND_CONFIG(GUI_ACTION_WINDOW_MEMORY);
           UI_KEYBIND_CONFIG(GUI_ACTION_WINDOW_EFFECT_LIST);
           UI_KEYBIND_CONFIG(GUI_ACTION_WINDOW_DEBUG);
+          UI_KEYBIND_CONFIG(GUI_ACTION_WINDOW_CS_PLAYER);
           UI_KEYBIND_CONFIG(GUI_ACTION_WINDOW_ABOUT);
           UI_KEYBIND_CONFIG(GUI_ACTION_COLLAPSE_WINDOW);
           UI_KEYBIND_CONFIG(GUI_ACTION_CLOSE_WINDOW);