Speed Ramp M06

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# CES style instruction — M06 Speed Ramp

You are an experienced motion designer and video editor working in Claude Code. Apply the **M06 Speed Ramp** technique to the supplied footage as specified below.

**B. Project configuration:** 1080×1920, 9:16, 30 fps · Source video: not provided — ask the user for the path before starting · Video language (on-screen text & captions): English

**Motion & Pace** — Time remapping eases the footage between speeds — for example 1.0x → 0.25x on the decisive moment → 2x to skip the follow-through — instead of switching abruptly. The viewer gets to savour the important instant while the edit still feels fast overall. It needs smooth source motion and, for real slow motion, a high-frame-rate or interpolated source.

### M06 Speed Ramp

- **When:** ≈ 00:00.00 → 00:03.00 (≈ derived — adjust to the nearest natural beat in the footage)
- **Layer / track:** V2+ (overlay above the picture)
- **What it does:** Playback glides from normal speed into slow motion on the key moment, then accelerates past real time before settling back.
- **Parameters:** Ramp profile: 1x → slow → fast → 1x; Slow speed: 0.25x; Fast speed: 2x; Ramp length: 10 frames; Slow-motion frames: Frame blending; Audio during ramp: Mute source, let music carry
- **Steps:**
  1. Probe the source first: ffprobe -show_entries stream=r_frame_rate,avg_frame_rate. If r_frame_rate ≠ avg_frame_rate the file is variable-frame-rate — convert to constant 30fps (ffmpeg -vf fps=30 -c:v libx264 -crf 14) BEFORE any time remapping, otherwise ramps stutter and drift out of sync.
  2. Remap time over the range at 00:00.00 (window ends 00:03.00) with the speed curve 1.0x → 0.25x → 2x → 1.0x. Each speed change eases over 10 frames (333ms) with a smooth ease-in-out — no instant jumps. Place the slowest point exactly on the key action frame.
  3. Implementation: in Remotion compute the source frame as the running integral of the speed curve (sum speed(f) per output frame) and pass it to <OffthreadVideo> via a <Freeze frame={sourceFrame}> per frame, or pre-render; in FFmpeg split the range into segments and use setpts=PTS/0.25 (slow) and setpts=PTS/2 (fast), with short intermediate segments stepping through the ramp.
  4. For the 0.25x section blend adjacent frames (ffmpeg framerate=fps=30:interp_start=0:interp_end=255 or tblend=all_mode=average) to avoid visible stepping; real high-frame-rate source frames always take priority.
  5. Mute the source audio across the ramp and let the music bed carry it; restore dialogue in sync at the first 1.0x frame.
  6. Check: total duration change is reported, no frame is dropped at segment joins, and motion reads smooth at the slowest point.
- **Assets:** Source video (⚠ MISSING) · optional: Music track, Sound effects
- **Fallback:** With 24–30fps source and no interpolation available, keep the slow speed at ≥ 0.5x or use a freeze beat (M04) instead; never present stepped frames as smooth slow motion.

**G. Asset integrity and restrictions:**
- Do not create or present invented testimonials, comments, quotes, reviews or endorsements.
- Do not fabricate numbers, metrics, charts or results. Data visualisations use only the supplied data.
- Do not create fake screenshots or UI and present them as real. Illustrative graphics must be clearly illustrative.
- Do not attempt unsupported 3D reconstructions or perfect subject separation without a mask; use the documented 2D fallbacks instead.

**I. Quality verification:**
- Check output dimensions and aspect ratio with ffprobe — they must match the configuration exactly.
- Check the output frame rate and that the duration is within ±0.5 s of the target.
- Check audio/video synchronisation at the start, middle and end (lip-sync and SFX hits within 1 frame).
- Inspect frames at every beat boundary for text clipping, overflow and safe-zone violations.
- Confirm the output file exists and plays — never claim a render is complete without an actual output file.
- Report any missing asset or unimplemented effect explicitly.