webm.py

Cross-platform command-line WebM converter.

Features

No Python dependencies, single source file
Supports encoding to VP8, VP9 and AV1, with Opus or Vorbis
2-pass encoding, user-friendly defaults, flexible set of options
Provides graphical interactive mode to cut/crop input video with mpv
Can burn subtitles, fit to limit, use external audio track and many more

Requirements

Python 2.7+ or 3.2+
FFmpeg 2+ compiled with libvpx and libopus
mpv 0.17+ compiled with Lua support, for interactive mode only

Make sure to set Add to PATH option in Python for Windows installer.

FFmpeg and mpv executables must be in PATH or set their location with
WEBM_FFMPEG and WEBM_MPV environment variables.

Installation

pip install webm

Or just save https://raw.githubusercontent.com/Kagami/webm.py/master/webm.py
and put in your PATH.

Windows, Python 2 and non-ASCII filenames

Unicode filenames won’t work on Windows with Python 2 due to Python bugs. Use
Python 3 if you can but if not an option set PYTHONIOENCODING environment
variable to utf-8 and run:

pip install subprocessww

Usage

Show help:

webm -h

Examples:

# VP9 with default quality
webm -i in.mkv
# Fit to 10 megabytes
webm -i in.mkv -l 10
# Set 1000kbps video bitrate
webm -i in.mkv -vb 1000
# Change quality
webm -i in.mkv -crf 20
# Encode to AV1
webm -i in.mkv -av1
# Encode to VP8 & Vorbis
webm -i in.mkv -vp8

Interactive mode

Pass -p flag to interactively select cut frargment and crop area with mpv.
Show help for interactive mode:

webm -hi

webm.py wiki contains some encoding
tricks and links to documentation on WebM/VPx.

License

webm.py is licensed under CC0.