Video Temporal Blend

MKRVideoTemporalBlend mixes each frame with the frames before it, producing that ghosted, smeared, long-exposure look - or, in its trail mode, light-streak motion. It's the node for "make this clip feel like a slow shutter" without owning a slow shutter, and it's a classic finishing trick for AI video: generated footage is often too crisp and too floaty, and a touch of temporal smear makes it read more like something a camera actually recorded.

Mechanically it's a sliding-window blend, per frame. blend_window (1–16, default 3) is how many frames back are considered; blend_strength (0–1, default 0.5) is how much of that average replaces the current frame. The mode input changes the character:

• mean - plain average of the window. Smooth, dreamy ghosting, like dragging the shutter. Best for a soft, filmic smear.
• motion_trail - the window frames are weighted so more recent ones count more, which stretches motion into streaks rather than a uniform ghost. That's your light-trail / comet effect.

The two controls interact: with a 3-frame window and 0.5 strength you get a subtle drift; crank the window to 12 and strength to 0.9 and motion dissolves into pure smear. At blend_strength 0 or a window of 1, it's a passthrough.

The inputs that matter

• blend_window - how many frames to look back. 3–5 is subtle; 8+ is heavy.
• blend_strength - how much of the blend replaces the current frame. Start at 0.3–0.5.
• mode - mean vs motion_trail, above.
• video, fallback_fps, output_format, filename_prefix, subfolder, overwrite - the standard pack inputs.

Outputs: video (MKR_VIDEO payload), output_path, summary.

Install

Part of MKRShift Nodes - install the pack:

cd ComfyUI/custom_nodes
git clone https://github.com/criskb/MKRShift_Nodes

or ComfyUI Manager → search MKRShift_Nodes → restart. mp4/mov/webm output needs system ffmpeg on PATH; gif/webp work without it. No pip dependencies.

Where people get burned

The big misunderstanding is thinking this is motion-blur-with-optical-flow. It's not - it's frame averaging, so fast motion produces ghosting (multiple visible copies) rather than clean directional blur. That's the look when you want it, but it's not a substitute for real motion blur. Second: fast-moving footage at a large blend_window will smear into an unreadable mess - use small windows on fast shots, big windows on slow, drifting ones. And the standard one: no audio carried through, since every frame is reprocessed.