Utility Merge Video is a simple, reliable ComfyUI workflow for stitching clips end-to-end. It uses two or four LoadVideo nodes to decode your source files into frame batches, passes them into the Utility Merge Videos (Subgraph) node (ID: fbb76376-8768-4ece-9b41-a646f5e46ac3), and concatenates those frame sequences in order. The merged frames are then written to disk with SaveVideo.

Technically, the subgraph concatenates batches rather than compositing them, so the result plays one clip after another. A switch inside the Utility Merge Videos subgraph lets you choose between 2-input and 4-input modes. All inputs must share the same resolution; otherwise, the graph will error at merge time. The SaveVideo node controls the output file path, format (via extension), and playback FPS; the final FPS you set there determines how the concatenated frames will play back. A MarkdownNote node in the graph provides quick reminders right where you work.