cryptomatte-api#

_images/test_image.png

About#

The cryptomatte-api is a fast, memory-efficient and robust library for loading, validating and decoding cryptomattes. It is meant to serve as a de-facto standard implementation of cryptomatte loading that is DCC-agnostic and runs as a standalone.

It is written entirely using C++20 while also providing pre-built python binaries that are pip-installable.

Features#

  • Robust and accurate decoding of cryptomattes (v1.2.0 spec)

  • Fully compliant with the specification

  • Extremely fast even at high resolutions

  • Very memory efficient

  • Rigorously tested

Performance#

The cryptomatte-api allows you to decode hundreds of cryptomattes for billions of pixels in less than a second. It is fast and efficient for both small and large images. During our benchmarks we test from just 320x140 pixels to 14480x8370 pixels for over 200 masks per-image.

We allow you to decode using in-memory compression or directly into a flat buffer giving you the flexibility to choose depending on your performance and memory needs.

A graph showing the relationship of pixels to the decoding time of all the masks ranging from 45ms to 1898ms following a slightly exponential growth curve. A graph showing the relationship of pixels to the memory usage of all the masks comparing the uncompressed data size to compressed. The memory usage for the masks peaks out at around 2.6GB towards the middle of the graph following a gaussian curve.

Quickstart#

This is a simple example of getting you up and running with the cryptomatte-api, loading a file from disk (which validates it) and then extract one or more masks from the image.

#include <cryptomatte/cryptomatte.h>

auto matte = cmatte::cryptomatte::load("from/disk/path", false /* load preview channels */);
auto mask = matte.mask("my_mask"); // will throw if 'my_mask' is not available
auto all_masks = matte.masks_compressed(); // get all the masks as compressed channels.

import cryptomatte_api as cmatte

matte = cmatte.Cryptomatte.load("from/disk/path", load_preview=False)
mask = matte.mask("my_mask") # will raise if 'my_mask' is not available
all_masks = matte.masks() # get all the masks of the cryptomatte mapped by names.

Contents#

Index

License#

BSD 3-Clause License

Copyright (c) 2025, Emil Dohne

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
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2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
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3. Neither the name of the copyright holder nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.

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