frame interpolation

Frame interpolation generates in-between frames to increase video frame rate or create smooth slow motion. **How it works**: Estimate motion (optical flow) between existing frames, warp and blend frames to synthesize intermediate frames. **Approaches**: **Flow-based**: Compute optical flow, backward warp frames, blend. **Learned synthesis**: End-to-end networks directly predict intermediate frames (FILM, RIFE, DAIN). **Kernel-based**: Predict adaptive convolution kernels for synthesis. **Key challenges**: Occlusion handling (revealed/hidden regions), large motions, complex scenes, temporal consistency. **Models**: RIFE (Real-Time Intermediate Flow Estimation) is fast with good quality. FILM (Google) offers high quality and handles motion blur. DAIN provides depth-aware interpolation. **Applications**: 24fps to 60fps conversion, slow motion from normal video, video restoration, animation smoothing, video stabilization. **Frame doubling**: 2x, 4x, 8x interpolation stacking for extreme slow-mo. **Artifacts**: Ghosting, warping artifacts in occlusion regions, temporal flicker. **Tools**: RIFE, Flowframes, Topaz Video AI, DaVinci Resolve plugins.