BoxToWide

This script automatically adjusts video aspect ratios in mpv. By default, it converts legacy 4:3 content to 16:9, but it can also handle other ratios using configurable range or precise checks.

It supports:

• Range-based detection for slightly off legacy ratios
• Accurate ratio detection with a tolerance for precise matching
• Flexible file/URL selection based on extensions or URLs
• Ideal for libraries with older or mixed aspect-ratio content, it streamlines widescreen conversion without manual intervention, while giving users full control over which checks to apply.

Options

To adjust options, simply change the values inside boxtowide.conf (recommended) or adjust local options within the script.

# file extensions the script will check
# separate each with a comma
video_exts=3gp,asf,avi,flv,m4v,mkv,mov,mp4,mp4v,mpeg,mpg,mts,ogv,rmvb,ts,webm,wmv

# target aspect ratio for conversion
# common ratios:
# 4:3 (1.3333), 16:9 (1.7778), 16:10 (1.6)
# 1.85:1, 2.00:1, 2.20:1, 2.35:1, 2.39:1, 2.76:1
target_ratio=16:9

# ratio check type (one or both can be used)
# check if aspect is within min_ratio to max_ratio
range_check=yes

# check if aspect matches accurate_ratio + accurate_tolerance
accurate_check=yes

# many old videos use weird ratios; usually 4:3 is ~1.3333
min_ratio=1.28
max_ratio=1.39

# common decimal ratios:
# 1.3333 (4:3), 1.7778 (16:9), 1.6 (16:10)
# 1.5 (3:2), 1.25 (5:4), 1.85 (1.85:1), 2.0 (2.00:1)
# 2.35 (2.35:1), 2.39 (2.39:1 scope)
accurate_ratio=1.3333

# allowed deviation; 0 = exact match
accurate_tolerance=0.01

# regex to detect urls (e.g. ytdl videos)
# a simpler pattern: "^%a+://"
url_pattern=^[%a][%a%d+.-]*://

How to install

Simply place boxtowide.lua in the corresponding mpv scripts location of your operating system:

• Windows: %APPDATA%\mpv\scripts\ or C:\users\USERNAME\AppData\Roaming\mpv\scripts\
• Linux: ~/.config/mpv/scripts/ or /home/USERNAME/.config/mpv/scripts/
• Mac: ~/.config/mpv/scripts/ or /Users/USERNAME/.config/mpv/scripts/

Note

More information about files locations can be found here

📁 mpv/
├── 📁 script-opts/
│   └── 📄 boxtowide.conf
└── 📁 scripts/
    └── 📄 boxtowide.lua