# `cavif` — PNG/JPEG to AVIF converter
Encoder/converter for AVIF images. Based on [rav1e](//lib.rs/rav1e) and [avif-serialize](https://lib.rs/avif-serialize), which makes it a pure Rust tool, with no C code!
## Installation
➡️ **[Download the latest release](https://github.com/kornelski/cavif/releases)** ⬅️
The pre-built zip includes a portable static executable, with no dependencies, that runs on any Linux distro. It also includes executables for macOS and Windows.
## Compatibility
* Chrome 85 desktop,
* Chrome on Android 12,
* Firefox 91.
## Running
Run in a terminal (hint: you don't need to type the path, terminals accept file drag'n'drop)
```bash
cavif image.png
```
It makes `image.avif`. You can adjust quality (it's in 1-100 scale):
```bash
cavif --quality 60 image.png
```
### Usage
You can also specify multiple images (encoding is multi-threaded, so the more, the better!).
```text
cavif [OPTIONS] IMAGES...
```
* `--quality=n` — Quality from 1 (worst) to 100 (best), the default value is 80. The numbers have different meaning than JPEG's quality scale. [Beware when comparing codecs](https://kornel.ski/faircomparison). There is no lossless compression support.
* `--speed=n` — Encoding speed between 1 (best, but slowest) and 10 (fastest, but a blurry mess), the default value is 4. Speeds 1 and 2 are unbelievably slow, but make files ~3-5% smaller. Speeds 7 and above degrade compression significantly, and are not recommended.
* `--overwrite` — Replace files if there's `.avif` already. By default the existing files are left untouched.
* `-o path` — Write images to this path (instead of `same-name.avif`). If multiple input files are specified, it's interpreted as a directory.
* `--quiet` — Don't print anything during conversion.
There are additional options that tweak AVIF color space. The defaults in `cavif` are chosen to be the best, so use these options only when you know it's necessary:
* `--premultiplied-alpha` — Alternative compression mode that lowers quality of semi-transparent colors. Warning: at low qualities it may create black artifacts in transparent areas.
* `--dirty-alpha` — Preserve RGB values of fully transparent pixels. By default irrelevant color of transparent pixels is cleared to avoid wasting space.
* `--color=rgb` — Encode using RGB instead of YCbCr color space. Makes colors closer to lossless, but makes files larger. Use only if you need to avoid even smallest color shifts.
## Building
To build it from source you need:
* Rust 1.52 or later, preferably via [rustup](https://rustup.rs),
* [`nasm`](https://www.nasm.us/) 2.14 or later.
Then run in a terminal:
```bash
cargo install cavif
```