Video ToolsLesson 290Free preview
Change Video Speed
This lesson is part of Web Developer Tools · All levels
Summary
The speed change feature speeds up or slows down video playback. At 2x, the duration is half; at 0.5x, the duration is doubled. The change in speed must be applied to video and audio simultaneously to keep both in sync. To slow down without changing the tone of sound, time-stretching techniques such as the atempo filter are needed.
Key points
- 2x the speed cut the duration in half, 0.5x the doubling.
- New duration = original duration divided by speed factor
- Naively speeding up audio can raise the pitch of the sound
- The atempo filter keeps the pitch when the audio tempo changes
- Video and audio must be changed together to keep synchronized.
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