Answers.Body: <p>The reciprocal of 75% i.e. 0.75 is 4/3 or 1.3333, so</p>
  
  <pre><code>ffmpeg -i combinedfullspeed.mp4 -filter_complex "[0:v]setpts=(4/3)*PTS[v];[0:a]atempo=0.75[a]" -map "[v]" -map "[a]" slow3.mp4
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-08-30T05:04:40.783Z
Answers.LastActivityDate: 2019-08-30T05:04:40.783Z
Answers.UserDisplayName: Gyan
Body: <p>I want to make a video play at 75% speed, so I used the following command:</p>
  
  <pre><code>ffmpeg -i combinedfullspeed.mp4 \
     -filter_complex "[0:v]setpts=1.25*PTS[v];[0:a]atempo=0.75[a]" \
     -map "[v]" -map "[a]" slow3.mp4
  </code></pre>
  
  <p>However, the video and audio are way out of sync. Any idea why?</p>
  
Tags: <ffmpeg>
Title: Audio and Video out of sync when slowing down
UserDisplayName: Ryan Z
ThreadText: # Audio and Video out of sync when slowing down
  
  (Asked by: username_0 on 2019-08-30)
  
  I want to make a video play at 75% speed, so I used the following command:
  
  ```
  ffmpeg -i combinedfullspeed.mp4 \
     -filter_complex "[0:v]setpts=1.25*PTS[v];[0:a]atempo=0.75[a]" \
     -map "[v]" -map "[a]" slow3.mp4
  
  ```
  
  However, the video and audio are way out of sync. Any idea why?
  
  **Tags:** ffmpeg
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2019-08-30. Score: 2 | Accepted answer
  
  The reciprocal of 75% i.e. 0.75 is 4/3 or 1.3333, so
  
  ```
  ffmpeg -i combinedfullspeed.mp4 -filter_complex "[0:v]setpts=(4/3)*PTS[v];[0:a]atempo=0.75[a]" -map "[v]" -map "[a]" slow3.mp4
  
  ```
  
  
  ---
  
  