diff --git a/README.md b/README.md
index f4a38f4..51712b4 100644
--- a/README.md
+++ b/README.md
@@ -26,11 +26,12 @@ All clips are exactly 8 seconds — the standard length for foley sound datasets
 
 - **Frame-accurate scrubbing** — click or drag the timeline; arrow keys and J/L for frame-by-frame, Shift for 1-second steps
 - **Batch export** — export multiple overlapping clips per cut point with configurable count and spread offset
-- **Two export formats** — H.264 MP4 with lossless PCM audio, or WebP image sequence (frames + `.wav`)
+- **Three export modes** — H.264 MP4 with lossless PCM audio, WebP image sequence (frames + `.wav`), or lossless/fast ffmpeg stream copy that preserves the source container
 - **Portrait crop** — crop to 9:16, 4:5, or 1:1 before export; click the video or crop bar to reposition
 - **Random portrait/square** — optionally apply a random crop to a subset of each batch
 - **Resize** — scale short side to a fixed pixel size (e.g. 512)
 - **Hardware encoding** — GPU-accelerated export via NVENC, VAAPI, QSV, AMF, or VideoToolbox
+- **Long clips** — clip duration is no longer capped at 30 seconds
 - **Subject tracking** — auto-adjust crop center using YOLOv8 detection (optional)
 
 ### Audio extraction & editing
diff --git a/core/ffmpeg.py b/core/ffmpeg.py
index faebe28..bfc7d96 100644
--- a/core/ffmpeg.py
+++ b/core/ffmpeg.py
@@ -82,11 +82,12 @@ def build_ffmpeg_command(
     target_fps: float | None = None,
     snap32: bool = False,
     frames: int | None = None,
+    stream_copy: bool = False,
 ) -> list[str]:
-    # -ss before -i: fast input-seeking. Safe here because we always re-encode,
-    # so there is no keyframe-alignment issue from pre-input seek.
+    # Re-encoded output is not constrained to source keyframes. Stream-copy
+    # output remains keyframe-limited even though it uses the same fast seek.
     # Image sequences always use libwebp, so skip HW encoder setup.
-    use_hw_vaapi = (encoder == "h264_vaapi" and not image_sequence
+    use_hw_vaapi = (not stream_copy and encoder == "h264_vaapi" and not image_sequence
                     and sys.platform == "linux")
     cmd = [_bin("ffmpeg"), "-y"]
 
@@ -96,6 +97,31 @@ def build_ffmpeg_command(
         cmd += ["-hwaccel", "vaapi", "-hwaccel_output_format", "vaapi",
                 "-vaapi_device", vaapi_dev]
 
+    if stream_copy:
+        incompatible = (
+            image_sequence or short_side is not None or portrait_ratio is not None
+            or target_fps is not None or snap32 or frames is not None
+        )
+        if incompatible:
+            raise ValueError("Stream copy cannot be combined with image or video transforms")
+        # Matroska/WebM input seeking can retain a whole cluster of keyframe
+        # pre-roll and then count -t from its shifted timestamps. Keeping source
+        # timestamps avoids that extension. MOV/MP4 needs normal timestamp
+        # rebasing instead, so this workaround is deliberately container-only.
+        ext = os.path.splitext(output_path)[1].lower()
+        timestamp_args = (
+            ["-copyts", "-start_at_zero"] if ext in (".mkv", ".webm") else []
+        )
+        return cmd + [
+            "-threads", "0",
+            "-ss", str(start),
+            "-i", input_path,
+            "-t", str(duration),
+            *timestamp_args,
+            "-c", "copy",
+            output_path,
+        ]
+
     cmd += [
         "-threads", "0",
         "-ss", str(start),
diff --git a/core/paths.py b/core/paths.py
index ed5a0b3..44621dd 100644
--- a/core/paths.py
+++ b/core/paths.py
@@ -25,14 +25,17 @@ def _log(*args) -> None:
 
 
 def build_export_path(folder: str, basename: str, counter: int,
-                      sub: int | None = None, tag: str | None = None) -> str:
+                      sub: int | None = None, tag: str | None = None,
+                      extension: str = ".mp4") -> str:
     """Build clip output path.  *folder* should be the vid folder (e.g. .../mp4/vid_001)."""
     name = f"{basename}_{counter:03d}"
     if tag is not None:
         name = f"{name}_{tag}"
     if sub is not None:
         name = f"{name}_{sub}"
-    return os.path.join(folder, name + ".mp4")
+    if extension and not extension.startswith("."):
+        extension = "." + extension
+    return os.path.join(folder, name + extension)
 
 
 def build_sequence_dir(folder: str, basename: str, counter: int,
diff --git a/main.py b/main.py
index ca9031f..e560cc8 100755
--- a/main.py
+++ b/main.py
@@ -119,7 +119,8 @@ class ExportWorker(QThread):
                  duration: float = 8.0,
                  target_fps: float | None = None,
                  snap32: bool = False,
-                 frames: int | None = None):
+                 frames: int | None = None,
+                 stream_copy: bool = False):
         super().__init__()
         self._input = input_path
         self._jobs = jobs  # [(start, output, portrait_ratio, crop_center), ...]
@@ -131,6 +132,7 @@ class ExportWorker(QThread):
         self._target_fps = target_fps   # LTX-2: force output fps (None = source)
         self._snap32 = snap32           # LTX-2: crop W/H down to ÷32
         self._frames = frames           # LTX-2: exact video frame count
+        self._stream_copy = stream_copy
         self._cancel = False
         self._procs: list[subprocess.Popen] = []
         self._procs_lock = __import__('threading').Lock()
@@ -146,7 +148,7 @@ class ExportWorker(QThread):
 
     def _run_one(self, start: float, output: str,
                   portrait_ratio: str | None, crop_center: float) -> str:
-        """Encode a single clip. Returns output path on success, raises on error."""
+        """Export a single clip. Returns output path on success, raises on error."""
         if self._cancel:
             raise RuntimeError("cancelled")
         if self._image_sequence:
@@ -154,7 +156,7 @@ class ExportWorker(QThread):
         cmd = build_ffmpeg_command(
             self._input, start, output,
             short_side=self._short_side,
-            portrait_ratio=portrait_ratio,
+            portrait_ratio=None if self._stream_copy else portrait_ratio,
             crop_center=crop_center,
             image_sequence=self._image_sequence,
             encoder=self._encoder,
@@ -162,15 +164,16 @@ class ExportWorker(QThread):
             target_fps=self._target_fps,
             snap32=self._snap32,
             frames=self._frames,
+            stream_copy=self._stream_copy,
         )
         proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
         with self._procs_lock:
             self._procs.append(proc)
         try:
-            _, stderr = proc.communicate(timeout=120)
-        except subprocess.TimeoutExpired:
-            proc.kill()
-            raise RuntimeError("ffmpeg timed out")
+            # Long-duration exports are valid; cancellation explicitly kills
+            # tracked ffmpeg processes, so an arbitrary wall-clock cap is not
+            # needed here.
+            _, stderr = proc.communicate()
         finally:
             with self._procs_lock:
                 self._procs.remove(proc)
@@ -182,7 +185,7 @@ class ExportWorker(QThread):
         if self._image_sequence:
             audio_cmd = build_audio_extract_command(self._input, start, output,
                                                        duration=self._duration)
-            subprocess.run(audio_cmd, capture_output=True, text=True, timeout=60)
+            subprocess.run(audio_cmd, capture_output=True, text=True)
         return output
 
     def run(self):
@@ -5170,8 +5173,22 @@ class MainWindow(QMainWindow):
             lambda v: self._settings.setValue("hw_encode", "true" if v else "false")
         )
 
+        self._chk_stream_copy = QCheckBox("Stream copy")
+        self._chk_stream_copy.setToolTip(
+            "Copy compressed video/audio without re-encoding (ffmpeg -c copy).\n"
+            "Very fast and lossless; cuts begin on source keyframes.\n"
+            "Preserves the source container and disables crop, resize, WebP, "
+            "LTX-2, and hardware encoding."
+        )
+        self._chk_stream_copy.setChecked(
+            self._settings.value("stream_copy", "false") == "true"
+        )
+        self._chk_stream_copy.toggled.connect(self._on_stream_copy_toggled)
+
         self._spn_clip_dur = QDoubleSpinBox()
-        self._spn_clip_dur.setRange(2.0, 30.0)
+        # QDoubleSpinBox requires a finite maximum; this is effectively
+        # unrestricted for media while removing the old 30-second ceiling.
+        self._spn_clip_dur.setRange(2.0, 999999999.0)
         self._spn_clip_dur.setSingleStep(0.5)
         self._spn_clip_dur.setSuffix("s")
         self._spn_clip_dur.setToolTip("Duration of each exported clip")
@@ -5839,9 +5856,11 @@ class MainWindow(QMainWindow):
         # Row 2: separator — annotation+folder │ encode
         g.addWidget(self._group_sep(), 2, 0, 1, 7)
         # Row 3: encode / clip params
-        g.addWidget(QLabel("Format:"), 3, 0); g.addWidget(self._cmb_format, 3, 1)
-        g.addWidget(self._chk_hw, 3, 2)
-        g.addWidget(QLabel("Resize:"), 3, 3); g.addWidget(self._spn_resize, 3, 4)
+        self._lbl_export_format = QLabel("Format:")
+        g.addWidget(self._lbl_export_format, 3, 0); g.addWidget(self._cmb_format, 3, 1)
+        g.addWidget(self._chk_stream_copy, 3, 2)
+        g.addWidget(self._chk_hw, 3, 3)
+        g.addWidget(QLabel("Resize:"), 3, 4); g.addWidget(self._spn_resize, 3, 5)
         # Row 4: separator — encode │ batch
         g.addWidget(self._group_sep(), 4, 0, 1, 7)
         # Row 5/6: batch params + actions
@@ -6398,6 +6417,64 @@ class MainWindow(QMainWindow):
             self._lbl_duration.setVisible(not is_ltx2)
         if is_ltx2 and self._spn_resize.value() == 0:
             self._spn_resize.setValue(512)  # LTX-2 default short side
+        self._update_stream_copy_controls()
+
+    def _stream_copy_active(self) -> bool:
+        """Whether the current tab can and should export with ``-c copy``."""
+        if not hasattr(self, "_chk_stream_copy"):
+            return False
+        pw = self._playlist
+        is_ltx2 = pw is not None and getattr(pw, "_mode", "foley") == "ltx2"
+        return self._chk_stream_copy.isChecked() and not is_ltx2
+
+    def _source_container_extension(self, path: str | None = None) -> str:
+        """Return the source suffix used for stream-copy output paths."""
+        suffix = os.path.splitext(path or self._file_path)[1]
+        return suffix or ".mkv"
+
+    @staticmethod
+    def _export_stem_exists(path: str) -> bool:
+        """Return True when this output stem exists in any export format."""
+        if os.path.exists(path):
+            return True
+        root, _extension = os.path.splitext(path)
+        if os.path.exists(root):  # WebP sequence directory
+            return True
+        folder = os.path.dirname(path)
+        stem = os.path.basename(root)
+        try:
+            return any(os.path.splitext(name)[0] == stem for name in os.listdir(folder))
+        except OSError:
+            return False
+
+    def _on_stream_copy_toggled(self, checked: bool) -> None:
+        self._settings.setValue("stream_copy", "true" if checked else "false")
+        self._update_stream_copy_controls()
+        self._update_next_label()
+
+    def _update_stream_copy_controls(self) -> None:
+        """Keep frame-transform controls mutually exclusive with stream copy."""
+        if not hasattr(self, "_chk_stream_copy"):
+            return
+        pw = self._playlist
+        is_ltx2 = pw is not None and getattr(pw, "_mode", "foley") == "ltx2"
+        self._chk_stream_copy.setEnabled(not is_ltx2)
+        active = self._chk_stream_copy.isChecked() and not is_ltx2
+
+        # WebP is a transcode. Keep the prior crop/resize values intact so
+        # turning stream copy off restores the user's encoding setup.
+        if active and self._cmb_format.currentText() != "MP4":
+            self._cmb_format.setCurrentText("MP4")
+        self._lbl_export_format.setVisible(not active)
+        self._cmb_format.setVisible(not active)
+        self._chk_hw.setEnabled(not active and bool(self._hw_encoders))
+        self._spn_resize.setEnabled(not active)
+        self._cmb_portrait.setEnabled(not active)
+        self._chk_rand_portrait.setEnabled(not active)
+        self._chk_rand_square.setEnabled(not active)
+        self._chk_track.setEnabled(not active)
+        self._crop_bar.setEnabled(not active)
+        self._rebuild_format_buttons()
 
     def _ltx2_export_params(self) -> dict | None:
         """Return LTX-2 ffmpeg kwargs for the active tab, or None for Foley."""
@@ -7306,9 +7383,11 @@ class MainWindow(QMainWindow):
             if idx >= 0:
                 self._cmb_portrait.setCurrentIndex(idx)
             fmt = meta["format"] or "MP4"
-            idx = self._cmb_format.findText(fmt)
-            if idx >= 0:
-                self._cmb_format.setCurrentIndex(idx)
+            self._chk_stream_copy.setChecked(fmt == "Source copy")
+            if fmt != "Source copy":
+                idx = self._cmb_format.findText(fmt)
+                if idx >= 0:
+                    self._cmb_format.setCurrentIndex(idx)
             if meta["clip_count"] is not None:
                 self._spn_clips.setValue(meta["clip_count"])
             if meta.get("clip_duration") is not None:
@@ -7403,6 +7482,8 @@ class MainWindow(QMainWindow):
             self._transport_row.removeWidget(btn)
             btn.setParent(None)
         self._format_btns.clear()
+        if self._stream_copy_active():
+            return
         formats = []
         ratio_text = self._cmb_portrait.currentText()
         if ratio_text != "Off":
@@ -9163,8 +9244,13 @@ class MainWindow(QMainWindow):
         folder = self._tab_export_folder()
         name = self._txt_name.text() or "clip"
         fmt = self._cmb_format.currentText()
-        image_sequence = fmt == "WebP sequence"
-        ext = "" if image_sequence else ".mp4"
+        stream_copy = self._stream_copy_active()
+        image_sequence = fmt == "WebP sequence" and not stream_copy
+        ext = (
+            "" if image_sequence else
+            self._source_container_extension(self._file_path) if stream_copy else
+            ".mp4"
+        )
         vid_name = self._get_vid_folder(folder)
         vid_folder = os.path.join(folder, vid_name)
         os.makedirs(vid_folder, exist_ok=True)
@@ -9196,8 +9282,8 @@ class MainWindow(QMainWindow):
                 jobs.append((start_t, out, None, 0.5))
                 positions.append((start_t, out))
 
-        short_side = self._spn_resize.value() or None
-        hw_on = self._chk_hw.isChecked() and self._hw_encoders
+        short_side = None if stream_copy else (self._spn_resize.value() or None)
+        hw_on = not stream_copy and self._chk_hw.isChecked() and self._hw_encoders
         encoder = self._hw_encoders[0] if hw_on else "libx264"
         max_workers = min(self._spn_workers.value(), 3) if hw_on else self._spn_workers.value()
         is_scan = getattr(self, '_auto_export_no_markers', False)
@@ -9223,13 +9309,14 @@ class MainWindow(QMainWindow):
             "clip_duration": clip_duration,
             "spread": spread,
             "folder": folder,
-            "format": fmt,
+            "format": "Source copy" if stream_copy else fmt,
             "profile": self._profile,
             "is_scan": is_scan,
             "replace_scan_exports": replace_scan_exports,
             "target_fps": ltx2["target_fps"] if ltx2 else None,
             "snap32": ltx2["snap32"] if ltx2 else False,
             "frames": ltx2["frames"] if ltx2 else None,
+            "stream_copy": stream_copy,
         }
 
         if self._export_worker and self._export_worker.isRunning():
@@ -9278,6 +9365,7 @@ class MainWindow(QMainWindow):
             target_fps=batch.get("target_fps"),
             snap32=batch.get("snap32", False),
             frames=batch.get("frames"),
+            stream_copy=batch.get("stream_copy", False),
         )
         self._export_worker.finished.connect(self._on_auto_clip_done)
         self._export_worker.all_done.connect(self._on_auto_batch_done)
@@ -9394,6 +9482,10 @@ class MainWindow(QMainWindow):
     def _update_next_label(self):
         folder = self._tab_export_folder()
         name = self._txt_name.text() or "clip"
+        extension = (
+            self._source_container_extension() if self._stream_copy_active()
+            else ".mp4"
+        )
         # The vid-folder lookup hits the DB and stats the disk and is stable for
         # a given (file, folder), so cache it — spinner ticks shouldn't repeat
         # it. The cheap m-counter probe is recomputed each call so it stays
@@ -9408,8 +9500,11 @@ class MainWindow(QMainWindow):
         self._export_counter = 1
         while True:
             tag = f"m{self._export_counter}"
-            if not os.path.exists(
-                    build_export_path(vid_folder, name, vid_num, sub=0, tag=tag)):
+            if not self._export_stem_exists(
+                    build_export_path(
+                        vid_folder, name, vid_num, sub=0, tag=tag,
+                        extension=extension,
+                    )):
                 break
             self._export_counter += 1
         n = self._spn_clips.value()
@@ -9438,7 +9533,9 @@ class MainWindow(QMainWindow):
                     break
 
         fmt = self._cmb_format.currentText()
-        image_sequence = fmt == "WebP sequence"
+        stream_copy = self._stream_copy_active()
+        image_sequence = fmt == "WebP sequence" and not stream_copy
+        extension = self._source_container_extension() if stream_copy else ".mp4"
         folder = self._tab_export_folder()
         if folder_suffix:
             folder = folder.rstrip(os.sep) + "_" + folder_suffix
@@ -9475,6 +9572,15 @@ class MainWindow(QMainWindow):
             # Group overwrite mode — re-export all sub-clips at this marker.
             # Delete old DB rows first to avoid duplicates on re-insert.
             group_paths = sorted(self._overwrite_group) if self._overwrite_group else [self._overwrite_path]
+            if stream_copy and any(
+                    os.path.splitext(path)[1].lower() != extension.lower()
+                    for path in group_paths):
+                self._show_status(
+                    "Stream-copy overwrite requires outputs with the source container; "
+                    "deselect the marker to create a new copy",
+                    6000,
+                )
+                return
             for path in group_paths:
                 self._db.delete_by_output_path(path)
             jobs = []
@@ -9509,8 +9615,11 @@ class MainWindow(QMainWindow):
                     if image_sequence:
                         p = build_sequence_dir(vid_folder, name, vid_num, sub=0, tag=tag)
                     else:
-                        p = build_export_path(vid_folder, name, vid_num, sub=0, tag=tag)
-                    if not os.path.exists(p):
+                        p = build_export_path(
+                            vid_folder, name, vid_num, sub=0, tag=tag,
+                            extension=extension,
+                        )
+                    if not self._export_stem_exists(p):
                         break
                     manual_n += 1
             else:
@@ -9522,7 +9631,10 @@ class MainWindow(QMainWindow):
                 if image_sequence:
                     out = build_sequence_dir(vid_folder, name, vid_num, sub=sub, tag=tag)
                 else:
-                    out = build_export_path(vid_folder, name, vid_num, sub=sub, tag=tag)
+                    out = build_export_path(
+                        vid_folder, name, vid_num, sub=sub, tag=tag,
+                        extension=extension,
+                    )
                 jobs.append((start, out, base_ratio, base_center))
 
             # Apply crop keyframes (or fall back to base state).
@@ -9558,7 +9670,7 @@ class MainWindow(QMainWindow):
                     jobs.append((s, o, ratio, center))
 
         # Subject tracking: re-detect crop center per sub-clip.
-        if self._chk_track.isChecked() and any(j[2] for j in jobs):
+        if not stream_copy and self._chk_track.isChecked() and any(j[2] for j in jobs):
             starts = [j[0] for j in jobs]
             self._show_status(f"Tracking subject across {len(jobs)} clip(s)…")
             QApplication.processEvents()
@@ -9570,7 +9682,7 @@ class MainWindow(QMainWindow):
                 for i, (s, o, r, c) in enumerate(jobs)
             ]
 
-        short_side = self._spn_resize.value() or None
+        short_side = None if stream_copy else (self._spn_resize.value() or None)
         duration = self._clip_dur
 
         # LTX-2 mode (active tab) overrides length/resize and feeds the
@@ -9585,9 +9697,11 @@ class MainWindow(QMainWindow):
         # Cursor is frozen here — user may move it during async export.
         self._export_cursor = self._cursor
         self._export_short_side = short_side
-        self._export_portrait = force_ratio or self._cmb_portrait.currentText()
+        self._export_portrait = (
+            "Off" if stream_copy else (force_ratio or self._cmb_portrait.currentText())
+        )
         self._export_crop_center = self._crop_center
-        self._export_format = fmt
+        self._export_format = "Source copy" if stream_copy else fmt
         self._export_clip_count = self._spn_clips.value()
         self._export_clip_duration = duration
         self._export_spread = self._spn_spread.value()
@@ -9606,12 +9720,13 @@ class MainWindow(QMainWindow):
         pending.append((self._cursor, counter, first_out, self._clip_span))
         self._timeline.set_markers(pending)
 
-        hw_on = self._chk_hw.isChecked() and self._hw_encoders
+        hw_on = not stream_copy and self._chk_hw.isChecked() and self._hw_encoders
         encoder = self._hw_encoders[0] if hw_on else "libx264"
         # GPU encoders have a limited number of concurrent sessions
         # (typically 3–5 on consumer NVIDIA cards), so cap workers.
         max_workers = min(self._spn_workers.value(), 3) if hw_on else self._spn_workers.value()
-        _log(f"Export: {len(jobs)} clip(s), encoder={encoder}, workers={max_workers}, "
+        mode = "stream-copy" if stream_copy else f"encoder={encoder}"
+        _log(f"Export: {len(jobs)} clip(s), {mode}, workers={max_workers}, "
              f"resize={short_side}, format={fmt}"
              + (f", ltx2 frames={ltx2['frames']}@{ltx2['target_fps']:g}fps" if ltx2 else ""))
         self._export_worker = ExportWorker(
@@ -9624,6 +9739,7 @@ class MainWindow(QMainWindow):
             target_fps=ltx2["target_fps"] if ltx2 else None,
             snap32=ltx2["snap32"] if ltx2 else False,
             frames=ltx2["frames"] if ltx2 else None,
+            stream_copy=stream_copy,
         )
         self._export_worker.finished.connect(self._on_clip_done)
         self._export_worker.all_done.connect(self._on_batch_done)
@@ -9780,7 +9896,9 @@ class MainWindow(QMainWindow):
 
         name = self._txt_name.text() or "clip"
         fmt = self._cmb_format.currentText()
-        image_sequence = fmt == "WebP sequence"
+        stream_copy = self._stream_copy_active()
+        image_sequence = fmt == "WebP sequence" and not stream_copy
+        extension = self._source_container_extension() if stream_copy else ".mp4"
 
         # Resolve vid folder BEFORE deleting DB rows, so we reuse the same one.
         vid_name = self._get_vid_folder(folder)
@@ -9811,8 +9929,11 @@ class MainWindow(QMainWindow):
         manual_n = 1
         while True:
             tag = f"m{manual_n}"
-            test = build_export_path(vid_folder, name, vid_num, sub=0, tag=tag)
-            if not os.path.exists(test):
+            test = build_export_path(
+                vid_folder, name, vid_num, sub=0, tag=tag,
+                extension=extension,
+            )
+            if not self._export_stem_exists(test):
                 break
             manual_n += 1
 
@@ -9835,7 +9956,10 @@ class MainWindow(QMainWindow):
                 if image_sequence:
                     out = build_sequence_dir(vid_folder, name, vid_num, sub=i, tag=tag)
                 else:
-                    out = build_export_path(vid_folder, name, vid_num, sub=i, tag=tag)
+                    out = build_export_path(
+                        vid_folder, name, vid_num, sub=i, tag=tag,
+                        extension=extension,
+                    )
                 jobs.append((start, out, ratio, center))
                 self._reexport_meta[os.path.normpath(out)] = {
                     "cursor": cursor_t,
@@ -9846,8 +9970,8 @@ class MainWindow(QMainWindow):
                     "crop_center": center,
                 }
 
-        short_side = self._spn_resize.value() or None
-        hw_on = self._chk_hw.isChecked() and self._hw_encoders
+        short_side = None if stream_copy else (self._spn_resize.value() or None)
+        hw_on = not stream_copy and self._chk_hw.isChecked() and self._hw_encoders
         encoder = self._hw_encoders[0] if hw_on else "libx264"
         max_workers = min(self._spn_workers.value(), 3) if hw_on else self._spn_workers.value()
         clip_dur = self._clip_dur
@@ -9864,6 +9988,10 @@ class MainWindow(QMainWindow):
         self._export_clip_duration = clip_dur
         self._export_folder = folder
         self._export_profile = self._profile
+        self._export_short_side = short_side
+        self._export_portrait = "Off" if stream_copy else self._cmb_portrait.currentText()
+        self._export_format = "Source copy" if stream_copy else fmt
+        self._export_stream_copy = stream_copy
 
         self._btn_export.setEnabled(False)
         self._btn_reexport.setEnabled(False)
@@ -9880,6 +10008,7 @@ class MainWindow(QMainWindow):
             target_fps=ltx2["target_fps"] if ltx2 else None,
             snap32=ltx2["snap32"] if ltx2 else False,
             frames=ltx2["frames"] if ltx2 else None,
+            stream_copy=stream_copy,
         )
         self._export_worker.finished.connect(self._on_reexport_clip_done)
         self._export_worker.all_done.connect(self._on_reexport_batch_done)
@@ -9896,10 +10025,13 @@ class MainWindow(QMainWindow):
             path,
             label=meta.get("label", ""),
             category=meta.get("category", ""),
-            short_side=self._spn_resize.value() or None,
-            portrait_ratio=meta.get("portrait_ratio", ""),
+            short_side=self._export_short_side,
+            portrait_ratio=(
+                "" if self._export_stream_copy
+                else meta.get("portrait_ratio", "")
+            ),
             crop_center=meta.get("crop_center", 0.5),
-            fmt=self._cmb_format.currentText(),
+            fmt=self._export_format,
             clip_count=meta.get("clip_count", 1),
             clip_duration=self._export_clip_duration,
             spread=self._spn_spread.value(),
diff --git a/tests/test_ui_structure.py b/tests/test_ui_structure.py
index a2f2018..accbc97 100644
--- a/tests/test_ui_structure.py
+++ b/tests/test_ui_structure.py
@@ -54,6 +54,27 @@ def test_workers_spinbox_in_export_tab(win):
     assert win._spn_workers in win._tab_export.findChildren(QSpinBox)
 
 
+def test_clip_duration_allows_long_exports(win):
+    assert win._spn_clip_dur.maximum() >= 86400.0
+
+
+def test_stream_copy_mode_disables_transforms(win):
+    win._file_path = "/x/source.mkv"
+    win._cmb_format.setCurrentText("WebP sequence")
+    win._chk_stream_copy.setChecked(True)
+    try:
+        assert win._stream_copy_active()
+        assert win._source_container_extension() == ".mkv"
+        assert win._cmb_format.currentText() == "MP4"
+        assert win._cmb_format.isHidden()
+        assert not win._chk_hw.isEnabled()
+        assert not win._spn_resize.isEnabled()
+        assert not win._cmb_portrait.isEnabled()
+        assert not win._chk_track.isEnabled()
+    finally:
+        win._chk_stream_copy.setChecked(False)
+
+
 def test_scan_button_in_audio_tab(win):
     from PyQt6.QtWidgets import QPushButton
     assert win._btn_scan in win._tab_audio.findChildren(QPushButton)
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 026ca52..0ed5c95 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -18,6 +18,10 @@ def test_build_export_path_sub():
     assert build_export_path("/out", "clip", 1, sub=0) == "/out/clip_001_0.mp4"
     assert build_export_path("/out", "clip", 1, sub=2) == "/out/clip_001_2.mp4"
 
+def test_build_export_path_custom_extension():
+    assert build_export_path("/out", "clip", 1, sub=0, extension=".mkv") == "/out/clip_001_0.mkv"
+    assert build_export_path("/out", "clip", 1, extension="mov") == "/out/clip_001.mov"
+
 def test_build_sequence_dir_sub():
     assert build_sequence_dir("/out", "clip", 1, sub=0) == "/out/clip_001_0"
     assert build_sequence_dir("/out", "clip", 1, sub=1) == "/out/clip_001_1"
@@ -54,6 +58,36 @@ def test_ffmpeg_command_with_resize():
     assert "scale" in vf_value
     assert cmd[-1] == "/out/clip_001.mp4"
 
+def test_ffmpeg_command_stream_copy():
+    cmd = build_ffmpeg_command(
+        "/in/video.mkv", 12.5, "/out/clip_001.mkv",
+        duration=3600.0, stream_copy=True,
+    )
+    assert cmd[cmd.index("-ss") + 1] == "12.5"
+    assert cmd[cmd.index("-t") + 1] == "3600.0"
+    assert cmd.index("-ss") < cmd.index("-i")
+    assert "-copyts" in cmd
+    assert "-start_at_zero" in cmd
+    assert cmd[cmd.index("-c") + 1] == "copy"
+    assert "-c:v" not in cmd
+    assert "-c:a" not in cmd
+    assert cmd[-1] == "/out/clip_001.mkv"
+
+def test_ffmpeg_command_stream_copy_rejects_transforms():
+    import pytest
+    with pytest.raises(ValueError, match="Stream copy"):
+        build_ffmpeg_command(
+            "/in/video.mkv", 0.0, "/out/clip.mkv",
+            short_side=256, stream_copy=True,
+        )
+
+def test_ffmpeg_command_stream_copy_mp4_uses_normal_timestamp_rebasing():
+    cmd = build_ffmpeg_command(
+        "/in/video.mp4", 12.5, "/out/clip.mp4", stream_copy=True,
+    )
+    assert "-copyts" not in cmd
+    assert "-start_at_zero" not in cmd
+
 
 def test_audio_clip_command_exact_length():
     cmd = build_audio_clip_command("/in/video.mp4", 12.5, 3.2, "/out/clip.wav")