Create time lapse video from images: Difference between revisions
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= Playback speed | = Playback speed 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: | 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)*(1*60+30)/(1*60+40) | setpts=(PTS-STARTPTS)*(1*60+30)/(1*60+40) | ||
= Cropping = | |||
My source is a set of pictures of size 1280 x 1024, by cropping this to 1280:800 I will have a 16:10 aspect ratio (which is a better fit for my screen). | |||
1280 * 10/160 = 800 | |||
I want to keep the bottom part of the picture so I need to move down by: | |||
1024 - 800 = 224 | |||
This results in the video filter option: | |||
crop=1280:800:0:224 | |||
= The complete example = | |||
<syntaxhighlight lang=bash> | <syntaxhighlight lang=bash> | ||
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-f concat -safe 0 -i "files.txt" | -f concat -safe 0 -i "files.txt" | ||
These options allow for this index-file format: | These options allow for this index-file format: | ||
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file '/full/path/to/file2.jpg' | file '/full/path/to/file2.jpg' | ||
... | ... | ||
Add music from mp3 file: | |||
-i "music.mp3" | |||
Video filter. Speedup video x2: | Video filter. Speedup video x2: | ||
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Output framerate: | Output framerate: | ||
-r | -r 25 | ||
Output codec: | Output codec: | ||
Revision as of 20:51, 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 "${sourcedir}/../out.mp4"
Playback speed and Music
The original video-length is the length when we create the video without 'setpts=~'. The images will be read as a stream of 25 pictures per second (input framerate=25). For example:
2500 pictures -> 2500/25 = 100 seconds of video = 1:40 minutes
Lets say you have some music and want to speed-up the video to match the music length:
Music length 1:30 minutes
Then use the following video filter to shorten the video by increasing the playback speed:
setpts=(PTS-STARTPTS) * <music-length> / <video-length>
You can add this option as a simple formula:
setpts=(PTS-STARTPTS)*(1*60+30)/(1*60+40)
Cropping
My source is a set of pictures of size 1280 x 1024, by cropping this to 1280:800 I will have a 16:10 aspect ratio (which is a better fit for my screen).
1280 * 10/160 = 800
I want to keep the bottom part of the picture so I need to move down by:
1024 - 800 = 224
This results in the video filter option:
crop=1280:800:0:224
The complete example
ffmpeg -f concat -safe 0 -i "${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"
These options allow for this index-file format:
file '/full/path/to/file1.jpg'
file '/full/path/to/file2.jpg'
...
Add music from mp3 file:
-i "music.mp3"
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 25
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:
