<p>Even though the first output is 400 fps. Normal graphics adapters or displays can't show 400 fps. Common refresh rates are 60 to 75 Hz, so the max number of frames per second that could have been displayed.</p>

<p>With a timelapse edit, the material naturally features higher stepping of scene changes between consecutive frames, so there's greater leeway to drop output framerate without a significant subjective difference.</p>

<p><em>ffmpeg also reports that most images were droped.</em></p>

<p>The input framerate is 400 and output is 25, so ffmpeg will select 25 out of every 400 input frames and drop the rest, in your command.</p>

<p><em>because people perceive 25fps as a smooth video</em></p>

<p>I think a century of cinema and video at similar rates should be confirmation.</p>

CC BY-SA 4.0
2018-05-28T13:41:36.810Z
So that means, if the time-lapse video has a higher frame rate than the maximum output frequency of my TV / screen, it is of no use. Right?

If my TV has 100Hz, the ffmpeg command would look like this:

`ffmpeg -r 400 -f concat -safe 0 -i list.tmp -r 100 -video_size hd1080 -vcodec libx264 -preset medium -crf 23 timelapse.mkv`

And if I want to use all the images I've taken:

`ffmpeg -r 100 -f concat -safe 0 -i list.tmp -r 100 -video_size hd1080 -vcodec libx264 -preset medium -crf 23 timelapse.mkv`
mrremo
CC BY-SA 4.0
2018-05-28T14:07:17.060Z
That's right...
Gyan
CC BY-SA 4.0
2018-05-28T13:10:29.013Z
2018-05-28T13:10:29.013Z
Gyan
<p>I'm doing a time-lapse film project about a six-month period. Now I write a script to process the thousands of photos. I use ffmpeg. The paths to the photos are in the list.tmp file and i'm using the concat option.</p>

<blockquote>
  <p>ffmpeg -r 400 -f concat -safe 0 -i list.tmp -video_size hd1080 -vcodec libx264 -preset medium -crf 23 timelapse.mkv</p>
</blockquote>

<p>With this command I get a time lapse with 400fps. 
If I now set the frame rate of the output video to 25fps, the film still looks the same <strong>subjective</strong>, but is a lot smaller (15mb instead of 60mb).</p>

<blockquote>
  <p>ffmpeg -r 400 -f concat -safe 0 -i list.tmp <strong>-r 25</strong> -video_size hd1080 -vcodec libx264 -preset medium -crf 23 timelapse.mkv</p>
</blockquote>

<p>ffmpeg also reports that most images were droped.</p>

<blockquote>
  <p>frame= 201 fps=3.7 q=-1.0 Lsize= 15647kB time=00:00:07.92 bitrate=16181.8kbits/s dup=0 <strong>drop=2989</strong> speed=0.148x</p>
</blockquote>

<p>Is it so, that I don't see the difference between 25fps and 400fps because people perceive 25fps as a smooth video?</p>

<p>Sorry for my English.</p>

<video><ffmpeg>
Framerate Timelapse
mrremo
# Framerate Timelapse

(Asked by: username_0 on 2018-05-28)

I'm doing a time-lapse film project about a six-month period. Now I write a script to process the thousands of photos. I use ffmpeg. The paths to the photos are in the list.tmp file and i'm using the concat option.

> ffmpeg -r 400 -f concat -safe 0 -i list.tmp -video\_size hd1080 -vcodec libx264 -preset medium -crf 23 timelapse.mkv

With this command I get a time lapse with 400fps.
If I now set the frame rate of the output video to 25fps, the film still looks the same **subjective**, but is a lot smaller (15mb instead of 60mb).

> ffmpeg -r 400 -f concat -safe 0 -i list.tmp **-r 25** -video\_size hd1080 -vcodec libx264 -preset medium -crf 23 timelapse.mkv

ffmpeg also reports that most images were droped.

> frame= 201 fps=3.7 q=-1.0 Lsize= 15647kB time=00:00:07.92 bitrate=16181.8kbits/s dup=0 **drop=2989** speed=0.148x

Is it so, that I don't see the difference between 25fps and 400fps because people perceive 25fps as a smooth video?

Sorry for my English.

**Tags:** video, ffmpeg


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## 1 answers

### Answer by username_1 on 2018-05-28. Score: 1

Even though the first output is 400 fps. Normal graphics adapters or displays can't show 400 fps. Common refresh rates are 60 to 75 Hz, so the max number of frames per second that could have been displayed.

With a timelapse edit, the material naturally features higher stepping of scene changes between consecutive frames, so there's greater leeway to drop output framerate without a significant subjective difference.

*ffmpeg also reports that most images were droped.*

The input framerate is 400 and output is 25, so ffmpeg will select 25 out of every 400 input frames and drop the rest, in your command.

*because people perceive 25fps as a smooth video*

I think a century of cinema and video at similar rates should be confirmation.

> **Comments:**
> **username_0**: So that means, if the time-lapse video has a higher frame rate than the maximum output frequency of my TV / screen, it is of no use. Right?  If my TV has 100Hz, the ffmpeg command would look like this:  `ffmpeg -r 400 -f concat -safe 0 -i list.tmp -r 100 -video_size hd1080 -vcodec libx264 -preset medium -crf 23 timelapse.mkv`  And if I want to use all the images I've taken:  `ffmpeg -r 100 -f concat -safe 0 -i list.tmp -r 100 -video_size hd1080 -vcodec libx264 -preset medium -crf 23 timelapse.mkv`  
> **username_1**: That's right...  

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