<p>I just found a way to do this by changing the parameters help by <strong>fps</strong> <strong>tbr</strong> <strong>tbn</strong> <strong>tbc</strong>; answer is derived from <a href="https://stackoverflow.com/a/52713677/6500909">this post</a>.</p>

<p><code>ffmpeg -y -i at25fps.mov -c:v copy -video_track_timescale 16 at16fps.mov</code></p>

<p>I am getting these remarks from Apple Sound Media Handler (so I am not sure if this is the best way to do it)</p>

<blockquote>
  <p>Non-monotonous DTS in output stream 0:0; previous: 0, current: 0; changing to 1. This may result in incorrect timestamps in the output file.</p>
  
  <p>Non-monotonous DTS in output stream 0:0; previous: 1, current: 1; changing to 2. This may result in incorrect timestamps in the output file.</p>
  
  <p>...</p>
</blockquote>

CC BY-SA 4.0
2019-01-26T21:20:32.990Z
2019-01-26T21:47:39.787Z
2019-01-26T21:47:39.787Z
MeSo2
<p>This works to change the speed, but it also changes the codec to MPEG4 Video (H264). </p>

<p><code>ffmpeg -y -r 16 -i at25fps.mov -filter:v "setpts=25/16*PTS" at16fps.mov</code></p>

<p>I need the codec to stay untouched: prores (HQ) (apch / 0x68637061), yuv422p10le(tv, progressive).</p>

<p>I found many similar post, but nothing worked:
<a href="https://video.stackexchange.com/questions/23674/how-to-change-framerate-with-ffmpeg-without-re-encoding">How to change framerate with ffmpeg without re-encoding?</a>, 
<a href="https://video.stackexchange.com/questions/21431/lower-framerate-without-re-encode">Lower framerate without re-encode</a></p>

<p><a href="https://superuser.com/questions/1159056/ffmpeg-recreate-timestamps-without-reencoding/1358974#1358974">This post</a> suggest I first extract the raw stream - how would I do that for a ProRes file?</p>

<video><ffmpeg><framerate><prores>
How to slow down ProRes file from 25fps to 16fps without re-encoding?
MeSo2
# How to slow down ProRes file from 25fps to 16fps without re-encoding?

(Asked by: username_0 on 2019-01-26)

This works to change the speed, but it also changes the codec to MPEG4 Video (H264).

`ffmpeg -y -r 16 -i at25fps.mov -filter:v "setpts=25/16*PTS" at16fps.mov`

I need the codec to stay untouched: prores (HQ) (apch / 0x68637061), yuv422p10le(tv, progressive).

I found many similar post, but nothing worked:
[How to change framerate with ffmpeg without re-encoding?](https://video.stackexchange.com/questions/23674/how-to-change-framerate-with-ffmpeg-without-re-encoding),
[Lower framerate without re-encode](https://video.stackexchange.com/questions/21431/lower-framerate-without-re-encode)

[This post](https://superuser.com/questions/1159056/ffmpeg-recreate-timestamps-without-reencoding/1358974#1358974) suggest I first extract the raw stream - how would I do that for a ProRes file?

**Tags:** video, ffmpeg, framerate, prores


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## 1 answers

### Answer by username_0 on 2019-01-26. Score: 0 | Accepted answer

I just found a way to do this by changing the parameters help by **fps** **tbr** **tbn** **tbc**; answer is derived from [this post](https://stackoverflow.com/a/52713677/6500909).

`ffmpeg -y -i at25fps.mov -c:v copy -video_track_timescale 16 at16fps.mov`

I am getting these remarks from Apple Sound Media Handler (so I am not sure if this is the best way to do it)

> Non-monotonous DTS in output stream 0:0; previous: 0, current: 0; changing to 1. This may result in incorrect timestamps in the output file.
>
> Non-monotonous DTS in output stream 0:0; previous: 1, current: 1; changing to 2. This may result in incorrect timestamps in the output file.
>
> ...


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