markdown OS X截屏到动画GIF

Posted 2021-05-05

# OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: *QuickTime and ffmpeg*.

Forked from https://gist.github.com/dergachev/4627207.  Updated to use a palette to improve quality and skip gifsicle. 

## Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

* Open "Quicktime Player", 
* Go to File -> New Screen Recording
* Selected screen portion by dragging a rectangle, recorded 13 second video. 
* Go to File -> Export -> As Movie
  * Saved the video in **full quality** with the filename `in.mov` 

Create a palette image from the video:

    ffmpeg -y -i in.mov -vf fps=10,palettegen palette.png

Convert into a GIF using the palette 
    
    ffmpeg -i in.mov -i palette.png -filter_complex "fps=10,paletteuse" out.gif

## Installation

The conversion process requires the following command-line tools:

* **ffmpeg** to process the video file

If you use homebrew and homebrew-cask software packages, just type this in: 

    brew install ffmpeg 
    
## Resources

* http://superuser.com/questions/556029/how-do-i-convert-a-video-to-gif-using-ffmpeg-with-reasonable-quality/556031#556031
* http://schneems.com/post/41104255619/use-gifs-in-your-pull-request-for-good-not-evil (primary source!)
* http://www.reddit.com/r/programming/comments/16zu7d/use_gifs_in_your_pull_requests_for_good_not_evil/
* http://superuser.com/questions/436056/how-can-i-get-ffmpeg-to-convert-a-mov-to-a-gif#_=_
* http://gnuski.blogspot.ca/2012/06/creating-animate-gif-with-free-software.html

## Related Ideas

* Extend https://github.com/dergachev/copy-public-url folder action for this use case
  * it would automate the conversion before copying Dropbox public URL
  * assign the folder action to ~/Dropbox/Public/Screenshots/gif
  * consider finding a way to simplify the dependency installation