github.com/srinathh/goanigiffy

GoAniGiffy

Animated GIFs have emerged as very convenient ways to post very short movie clips on the web. GoAniGiffy is a small utility written in Go language that converts a set of alphabetically sorted images (eg. frames extracted from a video with mplayer or VLC) into an animated GIF with the ability to crop, scale, rotate & flip the source images.

Requirements

You need to have the Go language installed to build GoAniGiffy

Installation

You should be able to use go get to install GoAniGiffy. This will get the source and create a binary built in your $GOPATH/bin folder

go get github.com

Usage

GoAniGiffy performs image operations in the order of cropping, scaling, rotating & flipping before converting the images into an Animated GIF. Image manipulation is done using Grigory Dryapak's imaging package. We use the Lanczos filter in Resizing and the default Floyd-Steinberg dithering provided by Go Language's image/gif package to ensure video quality. Arbitrary angle rotations are not supported.

The -delay parameter must be an integer specifying delay between frames in hundredths of a second. A value of 3 would give approximately 33 fps theoritically

Usage of goanigiffy:
  -cropheight=-1: height of cropped image, -1 specified full height
  -cropleft=0: left co-ordinate for crop to start
  -croptop=0: top co-ordinate for crop to start
  -cropwidth=-1: width of cropped image, -1 specifies full width
  -delay=3: delay time between frame in hundredths of a second
  -dest="movie.gif": a destination filename for the animated gif
  -flip="none": valid falues are none, horizontal, vertical
  -rotate=0: valid values are 0, 90, 180, 270
  -scale=1: scaling factor to apply if any
  -src="*.jpg": a glob pattern for source images. defaults to *.jpg
  -verbose=false: show in-process messages

Example

Here is the command line that builds movie.gif from the images in the sample folder.

goanigiffy -src="sample/*.jpg" -dest="sample/movie.gif" -cropleft=100 -croptop=280 -cropwidth=550 -cropheight=351 -scale=0.5 -rotate=270 -verbose

Tips

Here is an example of how you can extract frames from a video clip using mplayer. We are extracting JPEGs with quality of 80, starting from the 6th second & ending in the 8th second

mplayer -vo jpeg:quality=80 -nosound -ss 6 -endpos 8 vid.mp4

License

GoAniGiffy code is licensed under the Apache v2.0 license.

All other media files & documentation in the repository is licened under Creative Commons Attribution-ShareAlike 4.0 International License.