glyph — a modern ascii renderer

Converts images and videos into ASCII art.

Installing

Homebrew

brew install glyph

Build from source

zig build -Doptimize=ReleaseFast

The executable is placed at ./zig-out/bin.

To disable compiling ffmpeg and remove the libglyphav module:

zig build -Doptimize=ReleaseFast -Dav=false

Run directly with:

zig build run -Doptimize=ReleaseFast -- [options]

Usage

Basic usage (default Zig install path is ./zig-out/bin):

/path/to/glyph [options]

• -h, --help: Print help and exit
• -v, --version: Print version and exit
• -i, --input <str>: Input media file (image or video)
• -o, --output <str>: Output file (png/gif/mp4/… or .txt). Omit to render in terminal
• -c, --color: Use color ASCII characters
• -n, --invert_color: Invert color values
• -a, --auto_adjust: Auto-adjust brightness/contrast
• -s, --scale <f32>: Scale factor (default 1.0). Values >1 downscale (e.g., 2 halves size)
• --symbols <str>: Character set: ascii or block (default: ascii)
• -e, --detect_edges: Enable edge detection
• --sigma1 <f32>: DoG sigma1 (default 0.5)
• --sigma2 <f32>: DoG sigma2 (default 1.0)
• -b, --brightness_boost <f32>: Brightness multiplier (default 1.0)
• --full_characters: Use full character spectrum
• --ascii_chars <str>: Custom characters (default: " .:-=+*%#@")
• --disable_sort: Don’t sort --ascii_chars by size
• --block_size <u8>: ASCII block size (default 8)
• --threshold_disabled: Disable threshold
• --codec <str>: Encoder (e.g., libx264, libx265, hevc_nvenc, h264_videotoolbox)
• --keep_audio: Keep input audio in video output
• --stretched: Fit render to terminal window (stdout mode)
• -f, --frame_rate <f32>: Target fps for video output (default: input fps)
• -m, --mode <str>: ascii or pixels (default: ascii)
• -d, --dither <str>: none, floydstein, bayer4, bayer8, bayer16 (default: none)
• --dither_levels <u8>: Levels for ordered dither (default: 2)
• --fg <#rrggbb>: Foreground color (pixel mode)
• --bg <#rrggbb>: Background color (pixel mode)

To render to the terminal, omit --output. To save ASCII text, set an output with .txt extension.

FFmpeg Codec Support

Glyph includes FFmpeg with support for both software and hardware-accelerated codecs:

Software Codecs

• x264 (libx264) - H.264 video encoder
• x265 (libx265) - HEVC/H.265 video encoder
• libmp3lame - MP3 audio encoder
• libvorbis - Vorbis audio encoder

Hardware Codecs (Platform-dependent)

• NVIDIA NVENC (h264_nvenc, hevc_nvenc) - Available on Windows/Linux with NVIDIA GPUs
• VideoToolbox (h264_videotoolbox, hevc_videotoolbox) - Available on macOS

Use the --codec parameter to specify the encoder. For example:

# Software encoding
glyph -i input.mp4 -o output.mp4 --codec libx264

# Hardware encoding (NVIDIA)
glyph -i input.mp4 -o output.mp4 --codec h264_nvenc

# Hardware encoding (macOS)
glyph -i input.mp4 -o output.mp4 --codec h264_videotoolbox

Examples

Image

Basic usage:

glyph -i input.jpg -o output.png

Text output:

glyph -i input.jpg -o output.txt

Color:

glyph -i input.png -o output.png -c

Edge detection, color, downscale:

glyph -i input.jpeg -o output.png -s 4 -e -c

Dithering

glyph -i input.png -o output.png -a -s 2 --mode pixels --dither bayer8 --dither_levels 2

Terminal output:

glyph -i input.jpg -e -c -b 1.5

Video

Encode MP4 with NVENC, keep audio:

glyph -i /path/to/input.mp4 -o ascii.mp4 --codec hevc_nvenc --keep_audio

Render in terminal (fit to terminal):

glyph -i /path/to/input.mp4 --stretched -c

Custom encoder options (after --):

glyph -i /path/to/input.mp4 -o ascii.mp4 -c --codec libx264 -- --preset fast --crf 20

GIF output:

glyph -i /path/to/input.mp4 -o out.gif -s 2 -f 12