This repo contains tools used to compile Time-lapse movies using ffmpeg. The ffmpeg utility is controlled via the ffmpeg-python wrapper.
Example usage of this package can be found in the time-lapse scripts repository.
Using time-lapse to find tif files, and create a movie called 'test_movie' with 24 fps and deflickered:
from time_lapse import output, source
source_input = source.get_input(['*.tif'], fps=24, deflicker=7, filters=None)
output.create_outputs(source_input, 'test_movie', verbose=False)
This can also be done via the CLI:
timelapse --name test_movie --pattern "*.tif" --fps 24 --deflicker 7
By passing verbose=True to create outputs the following ffmpeg-python
inspection methods will be performed.
Show the ffmpeg command options ffmpeg-python would use:
.get_args()
By using graphviz the graph from input to output can be shown using:
.view()
This package requires the ffmpeg tool to be installed.
brew install ffmpeg
Then install this package:
pip install time-lapse
Additionally, when using the verbose output option a graph will be
rendered using graphviz, this requires the Graphviz library and the
related Python package:
brew install graphviz
pip install time-lapse[graph]
For near-universal compatibility the H.264 codec is used. The following section describe some of the choices for specific configuration options.
See the ffmpeg wiki for additional information: https://trac.ffmpeg.org/wiki/Encode/H.264
This uses -crf 20 to set a constant rate factor, which means the overall
quality of the movie should be constant. So bitrate varies to ensure
this. Higher value is lower quality. The quality and bit rates at this
value seem reasonable.
-preset slower is used to improve the compression ratio for the selected
quality (crf), without taking too much time.
-movflags +faststart is used to allow the movie to quickly start playing,
while it is still loading or buffering.
The codec defaults to YUV 444, which is not supported by Quicktime. So
add pix_fmt yuv420p to fix Quicktime support.
Use frames as input by giving a glob pattern which matches the desired
images. Usually these will be tiff images so use
-pattern_type glob -i "*.tiff".
When using image sequences as input the framerate of the desired output
should be given using -framerate 30.
Commonly used filters:
- Deflicker https://ffmpeg.org/ffmpeg-filters.html#toc-deflicker
- Scale https://ffmpeg.org/ffmpeg-filters.html#scale
- Crop https://ffmpeg.org/ffmpeg-filters.html#crop
- Drawtext https://ffmpeg.org/ffmpeg-filters.html#drawtext-1
- Video sizes https://ffmpeg.org/ffmpeg-utils.html#video-size-syntax
The optimal order for applying deflicker/scale/watermarking is the following:
- First deflicker the video to ensure it is equally deflickered for all outputs
- Then scale and crop the videos to fit the desired final resolutions
- Then add the watermark (which should not be deflickered and a constant size)
Add scaling to ensure it fits in given dimensions. Negative values for width or height make the encoder figure out the size by itself, keeping the aspect ratio of the source. The integer of the negative value, i.e. 4 for -4, means that the size should be devisble by that value. TODO: does it just scale/squish the video or crop?:
-vf scale=1920:-2
-vf scale=960:540:aspect..