diff --git a/movie_editor/frontend/block_sweep.js b/movie_editor/frontend/block_sweep.js
new file mode 100644
index 00000000..a809b523
--- /dev/null
+++ b/movie_editor/frontend/block_sweep.js
@@ -0,0 +1,113 @@
+// H3 block-repeat sweep: one scene, one fixed seed, several repeat configs run back to back
+// and captured into a labelled gallery — "what option produced what output" at a glance.
+// Each run is a one-off node_overrides on the built graph (store.runBlockRepeatSweep); the
+// project's own Engine Settings are never touched. A section of the unified Settings window,
+// sibling to Refinement & Taste — this IS the research tooling that rule asks for.
+(function () {
+  const { el, clear } = window.dom;
+  const API = window.MovieEditorAPI;
+
+  function _activeScenes() {
+    const st = window.Store.get();
+    return (st.project?.scenes || []).filter((s) => !s.excluded);
+  }
+
+  function _sceneLabel(s, i) {
+    return `Scene ${i + 1}` + (s.text ? ": " + s.text.substring(0, 30) : "");
+  }
+
+  function _card(item) {
+    const card = el("div", "media-card tmp-card");
+    const thumb = el("div", "media-thumb");
+    if (item.media) {
+      const vid = document.createElement("video");
+      vid.src = API.resultUrl(window.Store.get().project.id, item.media);
+      vid.controls = true; vid.muted = true; vid.playsInline = true; vid.preload = "metadata";
+      thumb.append(vid);
+    } else {
+      thumb.append(el("span", "media-icon", "✕"));
+    }
+    card.append(thumb);
+    const nameEl = el("div", "media-name", item.label);
+    nameEl.title = item.label;
+    card.append(nameEl);
+    return card;
+  }
+
+  function mount(container, ctx) {
+    const S = window.Store;
+    let sceneId = (_activeScenes()[0] || {}).id || null;
+    let configText = "";
+
+    container.append(el("div", "es-hint",
+      "Runs ONE scene through several H3 block-repeat configs back to back, same frame and "
+      + "seed throughout, so results are directly comparable. Nothing here touches your Engine "
+      + "Settings — every run is a one-off override on that run only."));
+
+    const sceneRow = el("div", "sw-stack");
+    const sceneSel = el("select");
+    _activeScenes().forEach((s, i) => sceneSel.append(new Option(_sceneLabel(s, i), s.id)));
+    if (sceneId) sceneSel.value = sceneId;
+    sceneSel.onchange = () => { sceneId = sceneSel.value; };
+    sceneRow.append(el("label", "sw-label", "Scene to sweep"), sceneSel);
+    container.append(sceneRow);
+
+    const expCb = el("input"); expCb.type = "checkbox";
+    const expLabel = el("label", "sw-hint");
+    expLabel.append(expCb, document.createTextNode(
+      " Show experimental config — unvalidated, results will not match any prior sweep 1:1 "
+      + "(different checkpoint/steps/sampler port nothing over, see the block-repeat research notes)"));
+    container.append(expLabel);
+
+    const cfgWrap = el("div", "sw-stack");
+    cfgWrap.hidden = true;
+    const cfgHint = el("div", "es-hint",
+      "One config per line: blocks;seam|noseam;times — e.g. 10,11,13;seam;5  or  40-41;noseam;1. "
+      + "Blocks accept a single number, a range (31-40), or a comma list; times is clamped to 1-4.");
+    const cfgArea = document.createElement("textarea");
+    cfgArea.className = "sw-textarea";
+    cfgArea.rows = 6;
+    cfgArea.placeholder = "10,11,13;seam;5\n40-41;noseam;1";
+    cfgArea.oninput = () => { configText = cfgArea.value; };
+    const runBtn = el("button", "btn primary tiny", "▶ Run sweep");
+    cfgWrap.append(cfgHint, cfgArea, runBtn);
+    container.append(cfgWrap);
+    expCb.onchange = () => { cfgWrap.hidden = !expCb.checked; };
+
+    const statusEl = el("div", "pj-meta");
+    container.append(statusEl);
+    const grid = el("div", "media-grid tmp-grid");
+    container.append(grid);
+
+    function render() {
+      const bs = S.get().blockSweep || {};
+      runBtn.disabled = !!bs.running;
+      runBtn.textContent = bs.running ? `Running ${bs.current || 0}/${bs.total || 0}…` : "▶ Run sweep";
+      statusEl.textContent = bs.running
+        ? `Sweeping (seed ${bs.seed}): ${bs.label || ""}`
+        : bs.error
+          ? "Stopped: " + bs.error
+          : (bs.results && bs.results.length ? `${bs.results.length} result(s), seed ${bs.seed}` : "");
+      clear(grid);
+      (bs.results || []).forEach((item) => grid.append(_card(item)));
+    }
+
+    runBtn.onclick = () => {
+      if (!sceneId) { alert("No scene to sweep."); return; }
+      S.runBlockRepeatSweep(sceneId, configText);
+    };
+
+    const unsub = S.subscribe(render);
+    render();
+    return unsub;
+  }
+
+  window.SettingsWindow.register({
+    id: "block_sweep", group: "Learning", order: 1, title: "H3 Block Repeat Sweep",
+    subtitle: "Run one scene through several block-repeat configs, compare results side by side.",
+    keywords: "h3 block repeat sweep span loop seam experimental research gallery batch",
+    iconBg: "linear-gradient(180deg,#b48bff,#6d3fd8)",
+    icon: '<svg viewBox="0 0 16 16" width="13" height="13"><path d="M2 3h4v4H2zM10 3h4v4h-4zM2 9h4v4H2zM10 9h4v4h-4z" fill="#fff"/></svg>',
+    mount,
+  });
+})();
diff --git a/movie_editor/frontend/block_sweep_config.test.js b/movie_editor/frontend/block_sweep_config.test.js
new file mode 100644
index 00000000..236340dc
--- /dev/null
+++ b/movie_editor/frontend/block_sweep_config.test.js
@@ -0,0 +1,47 @@
+// parseBlockSweepConfig: the "blocks;seam|noseam;times" line format for the H3 block-repeat
+// sweep panel, exercised rather than syntax-checked (see detail_verdict.test.js for why).
+const test = require("node:test");
+const assert = require("node:assert");
+const fs = require("node:fs");
+
+const src = fs.readFileSync(__dirname + "/store.js", "utf8");
+const grab = (name) => src.match(new RegExp(`function ${name}[\\s\\S]*?\\n  \\}\\n`))[0];
+const { parseBlockSweepConfig } = new Function(
+  grab("parseBlockSweepConfig") + "; return { parseBlockSweepConfig };")();
+
+test("parses blocks, seam and times off a semicolon line", () => {
+  const [c] = parseBlockSweepConfig("10,11,13;seam;5");
+  assert.equal(c.blocks, "10,11,13");
+  assert.equal(c.spanLoop, true);
+  assert.equal(c.times, 4); // clamped to the widget's max
+});
+
+test("noseam and in-range times pass through untouched", () => {
+  const [c] = parseBlockSweepConfig("40-41;noseam;1");
+  assert.equal(c.blocks, "40-41");
+  assert.equal(c.spanLoop, false);
+  assert.equal(c.times, 1);
+});
+
+test("multiple lines, blank lines and stray whitespace are skipped/trimmed", () => {
+  const out = parseBlockSweepConfig("\n 10,11;seam;2 \n\n40-41;noseam;1\n");
+  assert.equal(out.length, 2);
+  assert.equal(out[0].label, "10,11;seam;2");
+  assert.equal(out[1].label, "40-41;noseam;1");
+});
+
+test("a line with no blocks field is dropped, not crashed on", () => {
+  assert.deepEqual(parseBlockSweepConfig(";seam;2"), []);
+});
+
+test("missing/garbage times default to 1 rather than NaN", () => {
+  const [c] = parseBlockSweepConfig("35;seam;");
+  assert.equal(c.times, 1);
+  const [c2] = parseBlockSweepConfig("35;seam;abc");
+  assert.equal(c2.times, 1);
+});
+
+test("empty input yields no configs", () => {
+  assert.deepEqual(parseBlockSweepConfig(""), []);
+  assert.deepEqual(parseBlockSweepConfig(null), []);
+});
diff --git a/movie_editor/frontend/index.html b/movie_editor/frontend/index.html
index b03327fd..db971c43 100644
--- a/movie_editor/frontend/index.html
+++ b/movie_editor/frontend/index.html
@@ -146,6 +146,7 @@
   <script src="engine_settings.js"></script>
   <script src="editor_settings.js"></script>
   <script src="temp_browser.js"></script>
+  <script src="block_sweep.js"></script>
   <script src="custom_nodes.js"></script>
   <script src="autocomplete.js"></script>
   <script src="suggestions.js"></script>
diff --git a/movie_editor/frontend/player.js b/movie_editor/frontend/player.js
index 2871ed39..6f50a1bf 100644
--- a/movie_editor/frontend/player.js
+++ b/movie_editor/frontend/player.js
@@ -1238,6 +1238,25 @@
         };
 
         _transportEl.append(anchorSel, anchorBtn);
+
+        if (S.clipSaveableToMediaBin(_currentClip.sceneId)) {
+          const saveVidBtn = el("button", "btn ghost tiny", "🎬 Save video");
+          saveVidBtn.title = "Save this clip's render to the Media bin — server-side, no download/re-upload.";
+          saveVidBtn.onclick = async () => {
+            saveVidBtn.disabled = true; saveVidBtn.textContent = "Saving…";
+            try {
+              const entry = await S.saveClipToMediaBin(_currentClip.sceneId);
+              saveVidBtn.textContent = entry ? "✓ Saved" : "🎬 Save video";
+            } catch (e) {
+              alert("Save failed: " + e.message);
+              saveVidBtn.textContent = "🎬 Save video";
+            } finally {
+              saveVidBtn.disabled = false;
+              setTimeout(() => _renderTransport(), 1600);
+            }
+          };
+          _transportEl.append(saveVidBtn);
+        }
       }
     }
   }
diff --git a/movie_editor/frontend/store.js b/movie_editor/frontend/store.js
index 124d3348..13c1e634 100644
--- a/movie_editor/frontend/store.js
+++ b/movie_editor/frontend/store.js
@@ -3628,12 +3628,12 @@
     return [{ node: cfg.node, input: cfg.input, value: cfg.value }];
   }
 
-  async function _generateRun(sceneIds, onlyScene, prefix, resetSession) {
+  async function _generateRun(sceneIds, onlyScene, prefix, resetSession, extraOverrides) {
     _interrupted = false;
     _markGenInFlight(sceneIds);
     set({ gen: { state: "queuing", promptId: null, media: [], msg: `${prefix}: queuing…`, step: 0, maxStep: 0 } });
     try {
-      const overrides = _anchorGuideNodeOverrides(sceneIds);
+      const overrides = [...(_anchorGuideNodeOverrides(sceneIds) || []), ...(extraOverrides || [])];
       const r = await _retryOnTunnel(
         () => API.generate(state.project.id, onlyScene || null, onlyScene ? null : sceneIds, !!resetSession, overrides),
         10,
@@ -3681,6 +3681,55 @@
     }
   }
 
+  // H3 block-repeat sweep: one scene, one fixed seed, several repeat configs run back to
+  // back, each captured into a gallery labelled with the config that produced it. Every run
+  // is a one-off node_overrides on the BUILT graph (same mechanism as the anchor-guide i2v
+  // bypass above) — the project's own Engine Settings are never touched, so nothing needs
+  // restoring after and a crash mid-sweep leaves no residue.
+  // Line format: "blocks;seam|noseam;times", e.g. "10,11,13;seam;5" / "40-41;noseam;1".
+  function parseBlockSweepConfig(text) {
+    return String(text || "").split("\n").map((l) => l.trim()).filter(Boolean).map((line) => {
+      const [blocks, seam, times] = line.split(";").map((s) => (s || "").trim());
+      if (!blocks) return null;
+      return {
+        label: line, blocks,
+        spanLoop: seam.toLowerCase() === "seam",
+        times: Math.min(4, Math.max(1, parseInt(times, 10) || 1)),
+      };
+    }).filter(Boolean);
+  }
+
+  async function runBlockRepeatSweep(sceneId, configText) {
+    if (!state.project || !sceneId) return;
+    const configs = parseBlockSweepConfig(configText);
+    if (!configs.length) {
+      set({ blockSweep: { running: false, results: [], error: "No valid config lines — one per line, blocks;seam|noseam;times." } });
+      return;
+    }
+    // No seed variability: one seed for the whole sweep, chosen once, never persisted.
+    const seed = state.project.sampler_inputs?.seed ?? Math.floor(Math.random() * 0x7fffffff);
+    const results = [];
+    set({ blockSweep: { running: true, results, error: null, total: configs.length, current: 0, seed } });
+    for (let i = 0; i < configs.length; i++) {
+      const c = configs[i];
+      set({ blockSweep: { running: true, results: [...results], error: null, total: configs.length, current: i + 1, label: c.label, seed } });
+      const overrides = [
+        { node: "sampler", input: "seed", value: seed },
+        { node: "sampler", input: "h3_block_repeat", value: c.blocks },
+        { node: "sampler", input: "h3_block_repeat_span_loop", value: c.spanLoop },
+        { node: "sampler", input: "h3_block_repeat_times", value: c.times },
+      ];
+      const ok = await _generateRun([sceneId], sceneId, `Sweep ${i + 1}/${configs.length}: ${c.label}`, false, overrides);
+      if (!ok) {
+        set({ blockSweep: { running: false, results, error: `Stopped at "${c.label}": ${state.gen.msg}`, total: configs.length, seed } });
+        return;
+      }
+      const media = state.sceneRenders[sceneId]?.media;
+      results.push({ label: c.label, media });
+    }
+    set({ blockSweep: { running: false, results, error: null, total: configs.length, seed } });
+  }
+
   async function generate(onlyScene) {
     if (!state.project) return;
     try {
@@ -4007,6 +4056,22 @@
     }
   }
 
+  // Save one clip (by scene id) straight to the Media bin — server-side copy via the same
+  // import-clip route saveSelectedToMediaBin uses, no browser download/re-upload round trip.
+  // Used by the transport bar's "Save video" button for whatever clip is under the playhead.
+  async function saveClipToMediaBin(sceneId) {
+    if (!state.project) return null;
+    const spec = _clipExportSpecForScene(sceneId);
+    if (!spec) throw new Error("Nothing to save — generate this clip first.");
+    try {
+      const res = await API.importClipToMediaBin(spec.clip, spec.name);
+      await loadMedia();
+      return res?.media || res;
+    } catch (e) {
+      throw new Error(_friendlyGenError(e.message));
+    }
+  }
+
   async function saveSelectedToMediaBin() {
     if (!state.project) return;
     if (!_hasTimelineClipSelection()) { alert("Select a clip first."); return; }
@@ -4499,7 +4564,8 @@
     isOverlayAudioTrack, isSeparatedAudioTrack,
     resizeScene, setSceneGapAfter, splitScene, autoMontage, hasPlayableRender, snapFrames, snapFramesFloor, snapFramesCeil, sceneEffFrames, sceneEffFps, scenesOverridingProjectFrames, useProjectFramesEverywhere, setSourceTrim, trimSceneLeft, slipScene,
     applyEnginePreset, ENGINE_PRESETS, undo, redo,
-    refreshPreview, syncFromPreview, applyGlobalPromptQuiet, scheduleGlobalPromptApply, globalPromptApplyPending, buildGlobalPromptFromTimeline, syncGlobalPromptFromTimeline, generate: _clockedGenerate, generateMontage: _clockedMontage, generateSelected: _clockedSelected, genElapsed, selectedSceneCount, renderFinal, exportSelected, saveSelectedToMediaBin, clipSaveableToMediaBin, interrupt, loadModels, loadImageTargets, setModelInput, setModelBypass, setModelLink, clearNotice,
+    refreshPreview, syncFromPreview, applyGlobalPromptQuiet, scheduleGlobalPromptApply, globalPromptApplyPending, buildGlobalPromptFromTimeline, syncGlobalPromptFromTimeline, generate: _clockedGenerate, generateMontage: _clockedMontage, generateSelected: _clockedSelected, genElapsed, selectedSceneCount, renderFinal, exportSelected, saveSelectedToMediaBin, saveClipToMediaBin, clipSaveableToMediaBin,
+    runBlockRepeatSweep, parseBlockSweepConfig, interrupt, loadModels, loadImageTargets, setModelInput, setModelBypass, setModelLink, clearNotice,
     projectVariables, setProjectVariables, promptTemplates, savePromptTemplate, deletePromptTemplate, applyPromptTemplate,
     renamePromptTemplate, clearGlobalPrompt,
     setConditioningSlot, setSamplerSlot, setSamplerInput, setSamplerInputNow, unsetSamplerInput, setStudioInput, setStudioInputNow,
diff --git a/movie_editor/frontend/styles.css b/movie_editor/frontend/styles.css
index ecffae29..b2fdd6a1 100644
--- a/movie_editor/frontend/styles.css
+++ b/movie_editor/frontend/styles.css
@@ -2175,8 +2175,13 @@ body.tour-mode { overflow: hidden; }
 .sw-body { flex: 1; overflow: auto; padding: 16px 18px 24px; }
 
 /* grouped macOS-style rows (Refinement & Taste, Updates & ComfyUI) */
-.sw-stack { display: flex; flex-direction: column; }
+.sw-stack { display: flex; flex-direction: column; gap: 6px; margin-bottom: 12px; }
 .sw-hint { font-size: 11px; line-height: 1.5; color: var(--muted); margin-bottom: 12px; }
+.sw-label { font-size: 10px; font-weight: 700; letter-spacing: .5px; text-transform: uppercase;
+  color: var(--faint); }
+.sw-textarea { width: 100%; box-sizing: border-box; font-family: var(--font-mono, monospace);
+  font-size: 12px; padding: 8px; border: 1px solid var(--line); border-radius: 8px;
+  background: var(--ink-2); color: var(--text); resize: vertical; }
 .sw-rows-label { margin: 16px 4px 5px; font-size: 10px; font-weight: 700; letter-spacing: .6px;
   text-transform: uppercase; color: var(--faint); }
 .sw-rows { display: flex; flex-direction: column; border: 1px solid var(--line); border-radius: 10px;