🎥 sh2mp4

Records a shell command to an MP4 video, using xterm in a hidden desktop session.

This version is now written in Python. Use uvx sh2mp4 or pipx sh2mp4 to execute.

Usage

Record commands

# Basic recording
$ sh2mp4 "command to run" [output.mp4]

# With custom settings
$ sh2mp4 "htop" demo.mp4 --cols 120 --lines 40 --theme dark --font-size 14

# Live preview while recording
$ sh2mp4 "sl" train.mp4 --watch

Convert asciinema recordings

# Convert .cast files to MP4 (with window size optimization)
$ sh2mp4 --cast-file recording.cast output.mp4

# Fast conversion using speed multiplier (8x faster conversion time)
$ sh2mp4 --cast-file recording.cast output.mp4 --speed 8x

# Apply theme and font settings to cast conversion
$ sh2mp4 --cast-file demo.cast demo.mp4 --theme solarized-dark --font-size 16

# Watch the conversion in real-time
$ sh2mp4 --cast-file demo.cast demo.mp4 --watch

Utilities

# Check system dependencies
$ sh2mp4 --check-deps

# Measure available fonts and sizes
$ sh2mp4 --measure-fonts

Defaults

arg	value	description
command	(required)	Command or script to run in recording
output	output.mp4	Output file name
cols	`$(tput cols)`	Terminal width in characters
lines	`$(tput rows)`	Terminal height in characters
fps	30	Frames per second for recording
font	DejaVu Sans Mono	Font to use (must be monospace)
font_size	12	Font size in points (4,6,8,10,12,14,16,18,20)
theme	sh2mp4	Terminal color theme
watch	False	Show live preview during recording
cast_file	None	Convert asciinema .cast file instead
speed	None	Speed multiplier for fast cast conversion (2x, 4x, 8x)

Fonts

Font size is configurable (default 12pt). Character dimensions are automatically calculated based on the font size. Supported sizes: 4, 6, 8, 10, 12, 14, 16, 18, 20. Run sh2mp4 --measure-fonts to see pixel dimensions for all available fonts and sizes.

Themes

Available themes:

sh2mp4: Custom theme optimized for video recording (default)
tango: Tango-based theme
dark: High-contrast dark theme
light: Light theme
solarized-dark: Solarized Dark theme

You can customize or add new themes in the src/sh2mp4/themes.py file.

Speed Conversion

The --speed option accelerates cast file conversion without affecting the final video timing:

2x, 4x, 8x faster conversion: A 10-minute cast file with --speed 8x converts in ~1.25 minutes
Real-time output: Final MP4 plays at normal speed and maintains original timing
How it works:
1. Asciinema plays the cast file at accelerated speed (--speed 8x)
2. FFmpeg records at higher frame rate (8x normal fps)
3. Video is automatically slowed back down to real-time during encoding
Window optimization: Automatically scans cast file for maximum terminal dimensions to prevent text wrapping

# Convert a long recording quickly
$ sh2mp4 --cast-file long-session.cast output.mp4 --speed 8x

Dependencies

Run sh2mp4 --check-deps to see the full list of required system dependencies. The main requirements are:

ffmpeg (with libx264 support)
Xvfb (virtual framebuffer)
xterm (terminal emulator)
openbox (window manager)
Various X11 utilities (wmctrl, xdotool, unclutter)

You might want to run this in a container due to the number of dependencies.

License

WTFPL with one additional clause:

🛑 Don’t blame me

Do wtf you want, but you’re on your own.