Time Stretch

Change playback speed without changing pitch (and optionally vice-versa). rubberband is the quality engine — ffmpeg's atempo works for mild changes but artefacts at extremes; rubberband holds up to ~0.5×–2× cleanly.

When to use

• Podcast post: tighten an episode by 5–15% to match a pace target.
• Recover a slow recording without making the speaker sound chipmunked.
• Fit an audio file to a target duration (e.g. ad slot).
• Pitch-shift without changing duration (less common — singing/voice acting work).

Do not use this skill for:

• Beat-aligned tempo changes — that's a music-production concern not in scope.
• Sample-rate conversion — use convert-format.

Inputs