Convert MP4 file to animated WebP in ffmpeg

ffmpeg-mp4-to-animated-webp.md

Convert MP4 file to animated WEBP file in ffmpeg CLI

1. Install ffmpeg CLI through homebrew

In terminal.app, install ffmpeg through homebrew

brew install ffmpeg

Validate the installation:

which ffmpeg

Expect to see terminal returns the directory path of ffmpeg such as /usr/local/bin/ffmpeg

2. Set webp properties and convert

Example command which would convert an mp4 file to a lossless loop playing webp file in 20FPS with resolution 800px(width) * h600px(height):

ffmpeg -i input_filename.mp4 -vcodec libwebp -filter:v fps=fps=20 -lossless 1 -loop 0 -preset default -an -vsync 0 -s 800:600 output_filename.webp

Export an animated lossy WebP with preset mode picture：

ffmpeg -i input.mp4 -vcodec libwebp -filter:v fps=fps=20 -lossless 0  -compression_level 3 -q:v 70 -loop 1 -preset picture -an -vsync 0 -s 800:600 output.webp

primary options:

• set frame per second as 20: -filter:v fps=fps=20
• set output file lossless: -lossless 1
• set output webp file loop play: -loop 0. For non-loop, use -loop 1
• set rendering mode -preset default , can set as picture, photo, text, icon, drawing and none as needed. It would effect output file size. http://ffmpeg.org/ffmpeg-all.html#Options-28
• set output webp resolution as w800px * h600px -s 800:600

For more option details, please visit the the ffmpeg libwebp documentation

This method should applicable for majority video formats including .mov, .avi, .flv, etc. as input files as well as .gif format as output file.

Just leave it here for anyone who wants to set auto-size for width or height:

I used the tip @lamnhan066 posted to make a script that automatically crops black bars and optionally applies scaling to the result.

$ [SCALE=1] [FPS=20] vid2webp <input_file> [start_time] [end_time] [out_name]

No flags, just positional parameters for brevity. To set [end_time], [start_time] must be provided first. Set scale and framerate by ENV vars. Don't add .webp to [out_name], it will be added automatically. If not provided, out_name defaults to the original filename with .webp extension instead. If that file exists, it will add -1, -2, etc. to filename incrementally.

So, basic usage looks like this:

$ vid2webp vidfile.mp4 5 15
$ vid2webp vidfile.mp4 30 45
$ vid2webp vidfile.mp4 55 65 bonus
$ vid2webp vidfile.mp4 "00:03:22" "00:03:30.5"

Which outputs:

vidfile.webp
vidfile-1.webp
bonus.webp
vidfile-2.webp

To scale and convert entire video :

$ SCALE=0.5 vid2webp vidfile.mp4

More details and usage examples in the readme.