Create time lapse video from images: Difference between revisions

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= Tuning =
= Playback speed, Cropping and Music =
 
== Increase the playback speed ==
 
Increase the playback speed (x2), the resulting file will be smaller:
 
<syntaxhighlight lang=bash>
ffmpeg -f concat -safe 0 -i "${sourcedir}/../files.txt" -vf "setpts=(PTS-STARTPTS) / 2" -r 30 -vcodec libx264 -crf 22 "${sourcedir}/../out_fast.mp4"
</syntaxhighlight>
 
== Add music, crop ==


The original video-length is the length when we create the video without 'setpts=~'. The images will be read as a stream of 25 pictures per second (input framerate=25). For example:
The original video-length is the length when we create the video without 'setpts=~'. The images will be read as a stream of 25 pictures per second (input framerate=25). For example:
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   setpts=(PTS-STARTPTS) * <music-length> / <video-length>
   setpts=(PTS-STARTPTS) * <music-length> / <video-length>


You can input this as a simple formula:
You can add this option as a simple formula:


   setpts=(PTS-STARTPTS)*(1*60+30)/(1*60+40)
   setpts=(PTS-STARTPTS)*(1*60+30)/(1*60+40)


Complete example including crop:
Note: my source is a set of pictures of size 1280x1024, by cropping this to 1280:800 I will have a 16:10 aspect ratio:
 
Here is a complete example:


<syntaxhighlight lang=bash>
<syntaxhighlight lang=bash>
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= Overview of the used options =
= Overview of the used options =


Input indexfile 'files.txt':
Input index-file 'files.txt':


   -f concat -safe 0 -i "files.txt"
   -f concat -safe 0 -i "files.txt"
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   -i "music.mp3"
   -i "music.mp3"


These options allow for this indexfile format:
These options allow for this index-file format:


       file '/full/path/to/file1.jpg'
       file '/full/path/to/file1.jpg'
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   -r 30  
   -r 30  


Output codec and quality setting 'Constant Rate Factor'. For x264, this means setting a value somewhere between 18 and 26 for this CRF. The default is 23, and higher values will give you worse quality.
Output codec:
 
  -vcodec libx264
 
'Constant Rate Factor' quality setting. For x264, this means setting a value somewhere between 18 and 26 for this CRF. The default is 23, and higher values will give you worse quality.


   -vcodec libx264 -crf 22
   -crf 22


Sources:
Sources:

Revision as of 20:41, 21 March 2019


Create timelapse

Install ffmpeg: 

sudo apt install ffmpeg

Create timelapse indexfile: 

sourcedir=$HOME/Pictures/timelapse

find "${sourcedir}" -iname "*.jpg" -type f | sort | sed "s/\(.*\)/file '\1'/g"  > "${sourcedir}/../files.txt"

Create the video: 

ffmpeg -f concat -safe 0 -i "${sourcedir}/../files.txt" -r 25 -vcodec libx264 -crf 22 "${sourcedir}/../out.mp4"

Playback speed, Cropping and Music

The original video-length is the length when we create the video without 'setpts=~'. The images will be read as a stream of 25 pictures per second (input framerate=25). For example: 

 2500 pictures -> 2500/25 = 100 seconds of video = 1:40 minutes

Lets say you have some music and want to speed-up the video to match the music length: 

 Music length 1:30 minutes

Then use the following video filter to shorten the video by increasing the playback speed: 

 setpts=(PTS-STARTPTS) * <music-length> / <video-length>

You can add this option as a simple formula: 

 setpts=(PTS-STARTPTS)*(1*60+30)/(1*60+40)

Note: my source is a set of pictures of size 1280x1024, by cropping this to 1280:800 I will have a 16:10 aspect ratio:

Here is a complete example: 

ffmpeg -f concat -safe 0 -i "${sourcedir}/../files.txt" -i "${sourcedir}/../music.mp3" -filter:v "setpts=(PTS-STARTPTS)*(1*60+30)/(1*60+40), crop=1280:800:0:224" -r 35 -vcodec libx264 -crf 22 "${sourcedir}/../out.mp4"

Overview of the used options

Input index-file 'files.txt': 

 -f concat -safe 0 -i "files.txt"

Add music from mp3 file: 

 -i "music.mp3"

These options allow for this index-file format: 

     file '/full/path/to/file1.jpg'
     file '/full/path/to/file2.jpg'
     ...

Video filter. Speedup video x2: 

 -filter:v "setpts=(PTS-STARTPTS) / 2"

Video filter. crop=<width>:<height>:<left>:<top>: 

 -filter:v "crop=1280:800:0:224"

Output framerate: 

 -r 30

Output codec: 

 -vcodec libx264

'Constant Rate Factor' quality setting. For x264, this means setting a value somewhere between 18 and 26 for this CRF. The default is 23, and higher values will give you worse quality. 

 -crf 22

Sources:

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