kbalt / ezk-image

Convert between common image/video formats

EZK Image

ezk-image is a crate to perform conversion between common pixel formats and color spaces.

It uses SIMD and multi threading to accelerate the conversion when available, though multi-threading must be explicitly called with [convert_multi_thread].

Any format can be converted to any other format.

[Image] describes the conversion source and destination. It can store a window to only convert parts of an image, or to write the converted image into a part of the destination image.

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Supported Pixel formats

Bit depth of up to 16 bit per component is supported.

• I420
• I422
• I444
• NV12
• RGBA, BGRA
• RGB, BGR

Supported Color Primaries (color gamut)

• BT601NTSC
• BT709 (SDR)
• BT2020 (HDR)

Supported Color Transfer Functions (opto-electronic transfer characteristics of samples)

• Linear
• Gamma of 2.2 and 2.8
• SRGB
• SDR (BT.601, BT.709 and BT.2020)
• BT.2100 perceptual quantization (PQ)
• BT.2100 hybrid log-gamma (HLG)

Supported Color Spaces

• RGB
• YUV BT.601
• YUV BT.709
• YUV BT.2020
• ICtCp with perceptual quantization (PQ)
• ICtCp with hybrid log-gamma (HLG)

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Example

use ezk_image::*;

let (width, height) = (1920, 1080);

// Our source image, an RGB buffer
let rgb_image = vec![0u8; PixelFormat::RGB.buffer_size(width, height)];

// Our destination image, NV12 is a format that stores the image's luminosity and colors in the YUV space
let mut nv12_image = vec![0u8; PixelFormat::NV12.buffer_size(width, height)];

// Create the image we're converting from
let source = Image::new(
    PixelFormat::RGB,
    PixelFormatPlanes::RGB(&rgb_image[..]), // RGB only has one plane
    width,
    height,
    ColorInfo { // Describe the color of this image
        space: ColorSpace::BT709, // Doesn't really matter since we're not going to use the color.space in RGB images
        transfer: ColorTransfer::Linear,
        primaries: ColorPrimaries::BT709, // BT.709 is the most commonly used color gamut for SDR content
        full_range: false, // just like the ColorSpace, this isn't used in RGB images
    },
    8, // there's 8 bits per component (R, G or B)
).unwrap();

// Crate the image buffer we're converting to
let destination = Image::new(
    PixelFormat::NV12, // We're converting to NV12
    PixelFormatPlanes::infer_nv12(&mut nv12_image[..], width, height), // NV12 has 2 planes, `PixelFormatPlanes` has convenience functions to calculate them from a single buffer
    width,
    height,
    ColorInfo {
        space: ColorSpace::BT709, // NV12 is YUV so this is now relevant
        transfer: ColorTransfer::Linear,
        primaries: ColorPrimaries::BT709,
        full_range: false, // just like the ColorSpace this must now be considered, because the target is YUV
    },
    8, // there's 8 bits per component (Y, U or V)
).unwrap();

// Now convert the image data
convert_multi_thread(
    source,
    destination,
).unwrap();