<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>

CC BY-SA 4.0
2019-08-30T05:04:40.783Z
2019-08-30T05:04:40.783Z
Gyan
<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>

<ffmpeg>
Audio and Video out of sync when slowing down
Ryan Z
# 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


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## 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


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