created_at2021-04-08 16:15:53.970414
updated_at2023-10-07 11:34:09.071818
descriptionA high-level Rust wrapper for decoding and encoding WebP animations
Mika (blaind)



webp-animation   Build Status Latest Version Docs Version Lines of Code

A high-level Rust wrapper for decoding and encoding WebP animations


See examples/encode_animation.rs for source code of encoding the above image - example converted to gif for all-browser support, see the example.webp file

Underlying WebP format processing is handled by C-based libwebp library, which is interfaced through Rust libwebp-sys2 crate.

Functional Goals:

  • Easy-to-use API that looks like Rust
  • Enable decoding and encoding of WebP streams
  • All configuration flags provided by libwebp should be usable

Non-functional Goals:

  • High performance (approach libwebp performance without large overhead)
  • Write compherensive test cases, and test by automation
  • Ensure safety (no memory leaks or UB). Fuzz the API's. Safe to use for end users


  • Provide other WebP/libwebp -related functionality (such as image en/decoding or muxing). For this functionality, see e.g. libwebp-image or webp



Will take a webp buffer, and try to decode it to frame(s)

use webp_animation::prelude::*;

let buffer = std::fs::read("./data/animated.webp").unwrap();
let decoder = Decoder::new(&buffer).unwrap();

for frame in decoder.into_iter() {
  assert_eq!(frame.dimensions(), (400, 400));

  // w * h * rgba
  assert_eq!(frame.data().len(), 400 * 400 * 4);

  // if feature `image` is enabled (not by default),
  // one can convert data to [`Image::ImageBuffer`]
    (400, 400)

It is also possible to supply more decoding options through Decoder::new_with_options.


Will take n frames as an input. WebP binary data is output at the end (wrapped into WebPData which acts as a &[u8])

use webp_animation::prelude::*;

// setup
let dimensions = (64, 32);
let bright_frame = [255, 255, 255, 255].repeat(64 * 32);
let dark_frame = [0, 0, 0, 255].repeat(64 * 32);

// init encoder. uses by default lossless encoding,
// for other alternatives see documentation about
// `new_with_options`
let mut encoder = Encoder::new(dimensions).unwrap();

// insert frames to specific (increasing) timestamps
for frame_idx in 0..5 {
  let rgba_data = if frame_idx % 2 == 0 {
  } else {

  // (presentation) timestamp of the frame, should be in increasing order. represented in milliseconds
  let frame_timestamp_ms = frame_idx * 170;

  encoder.add_frame(rgba_data, frame_timestamp_ms).unwrap();

// final timestamp in milliseconds, until to the last frame is shown
let final_timestamp_ms = 1_000;

// get encoded webp data
let webp_data = encoder.finalize(final_timestamp_ms).unwrap();
std::fs::write("my_animation.webp", webp_data).unwrap();

See the documentation for other encoding options, e.g. for lossy encoding. For tuning the options, use the Encoder::new_with_options method.

Future plans

Keep up with upstream libwebp changes.

Possibly provide a compherensive CLI for working with WebP animations in future (conversions, optimizations, etc.)


Licensed under either of

at your option.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the software by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Commit count: 59

cargo fmt