CLI · Rust crate · v0.7.0

aether-renderer-core

PNG frames in, transparent video out. A folder, a ZIP or a stream on stdin becomes WebM, MOV, GIF or MP4, with the alpha intact, fades that go to transparent, and real progress.

Install

You need FFmpeg on your PATH:

brew install ffmpeg            # macOS
sudo apt install ffmpeg        # Ubuntu / Debian
winget install Gyan.FFmpeg     # Windows

Then install with Cargo, or download a binary:

cargo install aether-renderer-core

macOS · Apple Silicon macOS · Intel Windows Linux

Usage

# folder of PNGs -> transparent WebM at 30 fps
aether-renderer-core -i frames/ -o out.webm

# from a zip, as a GIF at 24 fps
aether-renderer-core -i frames.zip -o out.gif --fps 24

# for a video editor, with a soft 1 second fade in and out
aether-renderer-core -i frames/ -o out.mov --fade-in 1 --fade-out 1

# MP4 on the colour of the page it will sit on
aether-renderer-core -i frames/ -o out.mp4 --background '#1e1e1e'

# check a frame first: saves the middle frame as out.png
aether-renderer-core -i frames/ -o out.webm --preview

# PNG files back to back on stdin, straight from capture
aether-renderer-capture -i anim.html --stdout -d 4 | aether-renderer-core -i - -o out.webm --frames 120

Which format?

Format	Transparency	Best for
`webm`	✅	Websites (Chrome, Firefox, Edge), small files. The default.
`mov`	✅ full quality	Video editors: Premiere, DaVinci Resolve, Final Cut, After Effects
`gif`	✅ on/off per pixel	Chat, email, README files, anywhere video isn’t allowed
`mp4`	❌	Social media and maximum compatibility

The format follows the output file name, or set it with --format. Safari doesn't play transparent WebM; use GIF there, or MP4 on a matching --background.

All options

Option	Default	What it does
`-i, --input`	required	Folder or .zip with the frames, or - for a PNG stream on stdin
`--frames`		With -i -: how many frames the stream has (real progress; needed for --fade-out)
`-o, --output`	output.<format>	Output file
`--format`	from the extension, else webm	webm, mov, gif or mp4
`--fps`	30	Frames per second
`--file-pattern`	*.png	Glob (scene_*.png) or numbered sequence (frame_%04d.png)
`--background`	transparent (black for mp4)	Solid colour behind the frames: '#1e1e1e', white, transparent
`--fade-in / --fade-out`	0	Seconds to fade from / to transparent (or the background colour)
`--crf`	webm 30, mp4 23	Constant quality, lower is better
`--bitrate`		Target bitrate instead, e.g. 2M (--crf wins if both are set)
`--preview [N]`		Save frame N (default: the middle one) as a PNG instead of rendering
`-c, --config`		JSON or TOML config file (the command line wins)
`--progress json`		One JSON object per line on stdout, for GUIs and scripts
`-v, --verbose`		Details and a progress bar

Progress for other programs

With --progress json, every line on stdout is a JSON object, so a GUI or script can draw its own bar:

{"event":"progress","frame":0,"total_frames":360,"percent":0.0}
{"event":"progress","frame":96,"total_frames":360,"percent":26.67}
{"event":"progress","frame":360,"total_frames":360,"percent":100.0}

As a library

[dependencies]
aether-renderer-core = "0.7"

use aether_renderer_core::config::PartialConfig;

let cfg = PartialConfig {
    input: Some("frames".into()),
    output: Some("out.webm".into()),
    fps: Some(24),
    ..Default::default()
}
.into_config()?;

let report = aether_renderer_core::render_with_progress(cfg, |p| {
    println!("{:.0}% ({}/{} frames)", p.percent, p.frame, p.total_frames);
})?;
println!("{}", report.summary());

render_stream renders PNG files from any reader (no temp files), which is how the desktop app encodes a capture. Full API on docs.rs.

Source on GitHub · Changelog · Next: capture →