Derive external timeline duration from sections

js/ltx_director.js

@@ -11589,14 +11589,10 @@ app.registerExtension({
             return null;
           }
 
-          const rawDuration =
-            self._resolveNodeLinkedValue(timelineNode, "duration", { decimals: 3 }) ??
-            parseFloat(self._readNodeWidgetValue(timelineNode, "duration") || 0);
-          const duration = Math.max(0.1, Number.isFinite(rawDuration) ? rawDuration : 5.0);
-
           const sectionSetNode = self._findLinkedOriginNode(timelineNode, "section_set");
           const setClass = sectionSetNode?.comfyClass || sectionSetNode?.type || "";
           const sections = [];
+          let duration = 0;
           if (sectionSetNode && setClass === "TimelineSectionSetCS") {
             for (let i = 1; i <= 5; i++) {
               const sectionNode = self._findLinkedOriginNode(sectionSetNode, `section_${i}`);
@@ -11610,6 +11606,7 @@ app.registerExtension({
                 self._resolveNodeLinkedValue(sectionNode, "duration", { decimals: 3 }) ??
                 parseFloat(self._readNodeWidgetValue(sectionNode, "duration") || 0);
               const sectionDuration = Math.max(0.1, Number.isFinite(rawSectionDuration) ? rawSectionDuration : 1.0);
+              duration += sectionDuration;
               const imageSource = self._extractLinkedImageSource(sectionNode, "image");
               sections.push({
                 text,
@@ -11620,7 +11617,7 @@ app.registerExtension({
             }
           }
 
-          return { duration, sections };
+          return { duration: Math.max(0.1, duration), sections };
         };
         this._syncTimelineFromLink = function () {
           const payload = self._buildExternalTimelinePayload();

ltx_director.py

@@ -177,11 +177,10 @@ def _build_runtime_timeline_payload(external_timeline, frame_rate: float) -> tup
         return tdata, "", "", 0.0, 0
 
     sections = external_timeline.get("sections") or []
-    duration_seconds = max(0.1, float(external_timeline.get("duration") or 0.0))
-    duration_frames = max(1, int(round(duration_seconds * frame_rate)))
     current_start = 0
     local_prompts = []
     segment_lengths = []
+    total_duration_seconds = 0.0
 
     for index, section in enumerate(sections):
         if not isinstance(section, dict):
@@ -191,6 +190,7 @@ def _build_runtime_timeline_payload(external_timeline, frame_rate: float) -> tup
             continue
         section_seconds = max(0.1, float(section.get("duration") or 0.0))
         section_frames = max(1, int(round(section_seconds * frame_rate)))
+        total_duration_seconds += section_seconds
         seg = {
             "id": f"external_{index}",
             "start": current_start,
@@ -205,6 +205,8 @@ def _build_runtime_timeline_payload(external_timeline, frame_rate: float) -> tup
         segment_lengths.append(str(section_frames))
         current_start += section_frames
 
+    duration_seconds = max(0.1, float(total_duration_seconds or external_timeline.get("duration") or 0.0))
+    duration_frames = max(1, int(round(duration_seconds * frame_rate)))
     return tdata, " | ".join(local_prompts), ",".join(segment_lengths), duration_seconds, duration_frames
 
 

timeline_nodes.py

@@ -106,21 +106,13 @@ class Timeline(io.ComfyNode):
             node_id="TimelineCS",
             display_name="Timeline DUMAS",
             category="WhatDreamsCost DUMAS",
-            description="Builds an external timeline payload for LTX Director from a section set and total duration.",
+            description="Builds an external timeline payload for LTX Director from a section set, deriving the total duration from the sections.",
             inputs=[
                 TimelineSectionSetData.Input(
                     "section_set",
                     optional=True,
                     tooltip="Optional section set. When omitted, the timeline payload contains no sections.",
                 ),
-                io.Float.Input(
-                    "duration",
-                    default=5.0,
-                    min=0.1,
-                    max=1000.0,
-                    step=0.01,
-                    tooltip="Total timeline duration in seconds.",
-                ),
             ],
             outputs=[
                 TimelineData.Output(display_name="timeline"),
@@ -128,9 +120,11 @@ class Timeline(io.ComfyNode):
         )
 
     @classmethod
-    def execute(cls, section_set=None, duration=5.0) -> io.NodeOutput:
+    def execute(cls, section_set=None, duration=None) -> io.NodeOutput:
+        sections = list((section_set or {}).get("sections") or [])
+        total_duration = sum(max(0.1, float(item.get("duration") or 0.0)) for item in sections)
         payload = {
-            "duration": max(0.1, float(duration or 0.0)),
+            "duration": max(0.1, float(total_duration or 0.0)),
-            "sections": list((section_set or {}).get("sections") or []),
+            "sections": sections,
         }
         return io.NodeOutput(payload)