speed-up

Final retime of a finished short. Runs AFTER end-card and BEFORE qc-clip so the QC gate and visual-cadence measure (and save-local saves) the actual delivered, sped-up clip.

speed-up.sh <in.mp4> <out.mp4> [speed=1.25]

• speed — playback multiplier; 1.25 ships ~20% faster. Read from arg 3 or the SPEED env (default 1.25).
• Video is retimed with setpts=PTS/SPEED; audio with atempo (chained into 0.5–2.0 stages for out-of-range speeds) so pitch is preserved.
• Because it is a single uniform retime applied last, ALL upstream relative timing is preserved — nothing else in the pipeline needs to know about it. Note the cold-open title hold (TITLE_SWAP) is set pre-speed, so its on-screen time is TITLE_SWAP / SPEED.
• Deterministic (no Claude), idempotent (.spmeta mtime+param signature), non-fatal (probe/ffmpeg failure → passthrough copy).
• SPEED=1 or SPEED_UP=0 → passthrough.