Crate dcv_color_primitives

DCV color primitives is a library to perform image color model conversion.

It is able to convert the following pixel formats:

Source pixel format	Destination pixel formats
ARGB	I420, I444, NV12
BGR	I420, I444, NV12, RGB
BGRA	I420, I444, NV12, RGB
I420	BGRA, RGBA
I444	BGRA, RGBA
NV12	BGRA, RGB, RGBA
RGB	BGRA

The supported color models are:

• ycbcr, ITU-R Recommendation BT.601 (standard video system)
• ycbcr, ITU-R Recommendation BT.709 (CSC systems)

Both standard range (0-235) and full range (0-255) are supported.

Examples

Convert an image from bgra to nv12 (single plane) format, with Bt601 color space:

use dcv_color_primitives as dcp;
use dcp::{convert_image, ColorSpace, ImageFormat, PixelFormat};

fn convert() {
    const WIDTH: u32 = 640;
    const HEIGHT: u32 = 480;

    let src_data = Box::new([0u8; 4 * (WIDTH as usize) * (HEIGHT as usize)]);
    let mut dst_data = Box::new([0u8; 3 * (WIDTH as usize) * (HEIGHT as usize) / 2]);

    let src_format = ImageFormat {
        pixel_format: PixelFormat::Bgra,
        color_space: ColorSpace::Rgb,
        num_planes: 1,
    };

    let dst_format = ImageFormat {
        pixel_format: PixelFormat::Nv12,
        color_space: ColorSpace::Bt601,
        num_planes: 1,
    };

    convert_image(
        WIDTH,
        HEIGHT,
        &src_format,
        None,
        &[&*src_data],
        &dst_format,
        None,
        &mut [&mut *dst_data],
    );
}

Handle conversion errors:

use dcv_color_primitives as dcp;
use dcp::{convert_image, ColorSpace, ImageFormat, PixelFormat};
use std::error;

fn convert() -> Result<(), Box<dyn error::Error>> {
    const WIDTH: u32 = 640;
    const HEIGHT: u32 = 480;

    let src_data = Box::new([0u8; 4 * (WIDTH as usize) * (HEIGHT as usize)]);
    let mut dst_data = Box::new([0u8; 3 * (WIDTH as usize) * (HEIGHT as usize) / 2]);

    let src_format = ImageFormat {
        pixel_format: PixelFormat::Bgra,
        color_space: ColorSpace::Bt709,
        num_planes: 1,
    };

    let dst_format = ImageFormat {
        pixel_format: PixelFormat::Nv12,
        color_space: ColorSpace::Bt601,
        num_planes: 1,
    };

    convert_image(
        WIDTH,
        HEIGHT,
        &src_format,
        None,
        &[&*src_data],
        &dst_format,
        None,
        &mut [&mut *dst_data],
    )?;

    Ok(())
}

Compute how many bytes are needed to store and image of a given format and size:

use dcv_color_primitives as dcp;
use dcp::{get_buffers_size, ColorSpace, ImageFormat, PixelFormat};
use std::error;

fn compute_size() -> Result<(), Box<dyn error::Error>> {
    const WIDTH: u32 = 640;
    const HEIGHT: u32 = 480;
    const NUM_PLANES: u32 = 1;

    let format = ImageFormat {
        pixel_format: PixelFormat::Bgra,
        color_space: ColorSpace::Rgb,
        num_planes: NUM_PLANES,
    };

    let sizes: &mut [usize] = &mut [0usize; NUM_PLANES as usize];
    get_buffers_size(WIDTH, HEIGHT, &format, None, sizes)?;

    let buffer: Vec<_> = vec![0u8; sizes[0]];

    // Do something with buffer
    // --snip--

    Ok(())
}

Provide image planes to handle data scattered in multiple buffers that are not necessarily contiguous:

use dcv_color_primitives as dcp;
use dcp::{convert_image, get_buffers_size, ColorSpace, ImageFormat, PixelFormat};
use std::error;

fn convert() -> Result<(), Box<dyn error::Error>> {
    const WIDTH: u32 = 640;
    const HEIGHT: u32 = 480;
    const NUM_SRC_PLANES: u32 = 2;
    const NUM_DST_PLANES: u32 = 1;

    let src_format = ImageFormat {
        pixel_format: PixelFormat::Nv12,
        color_space: ColorSpace::Bt709,
        num_planes: NUM_SRC_PLANES,
    };

    let src_sizes: &mut [usize] = &mut [0usize; NUM_SRC_PLANES as usize];
    get_buffers_size(WIDTH, HEIGHT, &src_format, None, src_sizes)?;

    let src_y: Vec<_> = vec![0u8; src_sizes[0]];
    let src_uv: Vec<_> = vec![0u8; src_sizes[1]];

    let dst_format = ImageFormat {
        pixel_format: PixelFormat::Bgra,
        color_space: ColorSpace::Rgb,
        num_planes: NUM_DST_PLANES,
    };

    let dst_sizes: &mut [usize] = &mut [0usize; NUM_DST_PLANES as usize];
    get_buffers_size(WIDTH, HEIGHT, &dst_format, None, dst_sizes)?;

    let mut dst_rgba: Vec<_> = vec![0u8; dst_sizes[0]];

    convert_image(
        WIDTH,
        HEIGHT,
        &src_format,
        None,
        &[&src_y[..], &src_uv[..]],
        &dst_format,
        None,
        &mut [&mut dst_rgba[..]],
    )?;

    Ok(())
}

Provide image strides to convert data which is not tightly packed:

use dcv_color_primitives as dcp;
use dcp::{convert_image, get_buffers_size, ColorSpace, ImageFormat, PixelFormat};
use std::error;

fn convert() -> Result<(), Box<dyn error::Error>> {
    const WIDTH: u32 = 640;
    const HEIGHT: u32 = 480;
    const NUM_SRC_PLANES: u32 = 1;
    const NUM_DST_PLANES: u32 = 2;
    const RGB_STRIDE: usize = 4 * (((3 * (WIDTH as usize)) + 3) / 4);

    let src_format = ImageFormat {
        pixel_format: PixelFormat::Bgr,
        color_space: ColorSpace::Rgb,
        num_planes: NUM_SRC_PLANES,
    };

    let src_strides: &[usize] = &[RGB_STRIDE];

    let src_sizes: &mut [usize] = &mut [0usize; NUM_SRC_PLANES as usize];
    get_buffers_size(WIDTH, HEIGHT, &src_format, Some(src_strides), src_sizes)?;

    let src_rgba: Vec<_> = vec![0u8; src_sizes[0]];

    let dst_format = ImageFormat {
        pixel_format: PixelFormat::Nv12,
        color_space: ColorSpace::Bt709,
        num_planes: NUM_DST_PLANES,
    };

    let dst_sizes: &mut [usize] = &mut [0usize; NUM_DST_PLANES as usize];
    get_buffers_size(WIDTH, HEIGHT, &dst_format, None, dst_sizes)?;

    let mut dst_y: Vec<_> = vec![0u8; dst_sizes[0]];
    let mut dst_uv: Vec<_> = vec![0u8; dst_sizes[1]];

    convert_image(
        WIDTH,
        HEIGHT,
        &src_format,
        Some(src_strides),
        &[&src_rgba[..]],
        &dst_format,
        None,
        &mut [&mut dst_y[..], &mut dst_uv[..]],
    )?;

    Ok(())
}

Structs

• ImageFormat
  Describes how the image data is laid out in memory and its color space.

Enums

• ColorSpace
  An enumeration of supported color models.
• ErrorKind
  An enumeration of errors.
• PixelFormat
  An enumeration of supported pixel formats.

Constants

• STRIDE_AUTO
  If a plane stride is assigned to this constant, the plane will be assumed to contain packed data

Functions

• convert_image
  Converts from a color space to another one, applying downsampling/upsampling to match destination image format.
• describe_acceleration
  Returns a description of the algorithms that are best for the running cpu and available instruction sets
• get_buffers_size
  Compute number of bytes required to store an image given its format, dimensions and optionally its strides