MotionBlur

MotionBlur belongs to Resolve FX Temporal and is available in DaVinci Resolve Studio. Blackmagic describes it as the Resolve FX version of the Motion Blur panel in the Color page Motion Effects palette. It analyzes movement inside a clip and adds artificial motion blur where image elements are actually moving.

The node exposes one visible Image Input, but its processing is temporal: motion estimation uses neighboring frames. One cable in the Flow therefore does not imply single-frame processing. Clip boundaries, edits, flashes and abrupt temporal discontinuities deserve special inspection.

Its central advantage over DirectionalBlur is local motion direction. DirectionalBlur applies one chosen global direction, whereas MotionBlur tries to infer different speed and direction for different moving regions. For a simple uniform graphic move, DirectionalBlur can still be cheaper and more predictable.

Do not confuse this Resolve FX with Motion Blur in the Settings tab of Transform, Text+ and other motion-producing Fusion tools. Settings Motion Blur can use known parameter animation and a virtual shutter; this MotionBlur sees rendered pixels and must infer their motion with optical flow.

Do not confuse it with VectorMotionBlur either. VectorMotionBlur is intended for workflows where motion-vector data already exists or has been generated separately. The MotionBlur topology documented here has no separate vector input because motion estimation is internal to the effect.

Mo. Est. Type controls the quality/performance tradeoff of motion mapping. Resolve 21 explicitly describes Better as more accurate and more processor intensive, while Faster is more approximate and less demanding. Better cannot guarantee artifact-free results on occlusion, crossings or newly revealed areas.

The captured Fusion Inspector shows None, Faster and Better under Mo. Est. Type. The current Resolve 21 Motion Blur section documents Faster and Better but does not publish a separate None behavior for this effect. None is therefore recorded as a UI-confirmed option and a live-verification boundary rather than borrowing semantics from Temporal NR.

Motion Range determines what speed of movement to consider while defining regions to blur. The UI offers Small, Medium and Large. A useful production habit is to start with the smallest range that reliably covers the shot and expand only when fast motion is not being mapped correctly.

Motion Blur is the effect amount from 0 to 100. Blackmagic states that 0 adds no motion blur and 100 applies the maximum. It is not a shutter angle in degrees and not the length parameter of DirectionalBlur. Judge it during playback at the real clip cadence.

Blur Direction sets the temporal orientation of the smear relative to the current frame: Both Directions, From Previous Frame or Towards Next Frame. This is not a spatial angle. A bright fast-moving object against a dark background makes the difference easy to see.

Granularity is documented as adjusting how much detail is added to the blur. That wording is safer than inventing a published sample count, subdivision count or internal normalization because the user-facing manual does not expose those implementation details.

Effect Mask only limits spatial contribution of the processed result. It is not a motion-vector map and does not tell the effect how the subject moves. Track the mask separately when coverage must follow a moving object.

Common failure cases for optical flow include object crossings, disocclusion, transparency, hair, fences, water, smoke, flashes, noise and grain. Look for tearing, doubled edges, rubbery smears and blur appearing on nominally static details rather than judging only overall softness.

For a finishing pipeline, lock edit timing and retiming before motion estimation when possible, then add final grain or high-frequency texture after the temporal effect. Otherwise texture may complicate correspondence between neighboring frames.

MotionBlur cannot repair poor animation timing or reconstruct physically perfect information where an object is hidden in one frame and revealed in another. Treat it as a finishing tool: make the motion correct first, then use blur to reduce strobing and better resemble camera exposure.