Timestretch Audio and Video Using 'Rubberband' Filter

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The following command will be a video that plays at half speed with audio that’s both slowed down and pitched down by an octave.

Note: To enable compilation of this filter, you need to configure FFmpeg with --enable-librubberband.

librubberband also support amazing time stretching capability (i.e.: slowdown the audio without changing the pitch). To achieve that, remove the pitch=0.5 or set it to 1.

Filter chain breakdown

  • Video Processing (aka [v]): setpts=2.0*PTS: multiplies the presentation timestamps by 2.0, effectively slowing the video to half speed.

  • Audio Processing (aka [a]): rubberband=tempo=0.5:pitch=0.5: tempo=0.5 slow down the audio to half speed and pitch=0.5 lower the pitch by one octave.

Video Explanation

  • 00-15: The original video clip
  • 15-30: Video slowdown using setpts=2.0*PTS and atempo=0.5
  • 30-45: Video slowdown and rubberband=tempo=0.5
  • 45-60: Video slowdown and rubberband=tempo=0.5:pitch=0.5

Refer to the ffmpeg documentation for more info about Rubberband filter.

ffmpeg input.mp4 -filter_complex "[0:v]setpts=2.0*PTS[v];[0:a]rubberband=tempo=0.5:pitch=0.5[a]" -map "[v]" -map "[a]" output-tempo-pitch-0.5.mp4