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📘 FRAME INTERPOLATION DOCUMENTATION
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NAME:
    Frame Interpolation

PURPOSE:
    Create smooth slow-motion or higher-FPS video from a standard input file.
    Useful for turning 24 FPS or 30 FPS footage into 48 FPS, 60 FPS, or higher
    frame rates for cinematic or broadcast-ready results.

SUPPORTED ENGINES:
    • ffmpeg (default) — uses minterpolate for motion-compensated synthesis
    • rife-ncnn (scaffold only, external binary required)
    • dain-ncnn (scaffold only, external binary required)

USAGE:
    videobeaux -P frame_interpolate -i INPUT --outfile OUTPUT [options]

REQUIRED:
    --outfile      Path to the resulting file. (Do NOT use global -o.)

FPS OPTIONS:
    --fps N        Target frame rate (e.g., 60, 120).
    --multiplier X Multiply input FPS by X (e.g., 2.0 → 30→60). Ignored if --fps is given.

ENGINE OPTIONS:
    --engine {ffmpeg|rife-ncnn|dain-ncnn}
                   Select interpolation backend. Default: ffmpeg.

FFMPEG FILTER SETTINGS:
    --mi-mode {dup,blend,mci}      Motion interpolation mode (default mci)
    --me-mode {bidir,bilat}        Motion estimation mode (default bidir)
    --mc-mode {obmc,aobmc}         Motion compensation mode (default aobmc)
    --vsbmc {0,1}                  Variable-size block motion comp (default 1)
    --scd {none,fdiff,mv}          Scene-change detection (default fdiff)

ENCODING CONTROLS:
    --x264-preset PRESET           libx264 preset (ultrafast..placebo, default medium)
    --crf VALUE                    Constant Rate Factor (default 18)
    --copy-audio                   Copy audio instead of re-encoding

ADVANCED:
    --profile {quality,balanced,speed}
        • quality  = maximum smoothness & accuracy
        • balanced = sensible default between speed & quality
        • speed    = fastest possible transcode

    --encoder {x264,vt_h264,vt_hevc}
        • x264     = CPU software encoder
        • vt_h264  = macOS hardware encoder (VideoToolbox, AVC)
        • vt_hevc  = macOS hardware encoder (VideoToolbox, HEVC)

    --bitrate VALUE
        Target bitrate for VideoToolbox encoders (e.g., 8M, 10M).

    --threads N
        Set FFmpeg -threads and -filter_threads for manual CPU control.

NOTES:
    • Use --multiplier if you don’t know source FPS (auto-detected via ffprobe).
    • For faster turnaround, combine --profile speed with VideoToolbox.
    • Use lower FPS targets (48–50) for smoother renders with shorter transcode time.
    • All processed videos are tagged as BT.709 color space for player consistency.

EXAMPLES:
    See “frame_interpolate_examples.txt” for ready-to-run command examples.

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