Enum re_renderer::resource_managers::yuv_converter::YuvPixelLayout

pub enum YuvPixelLayout {
    Y_U_V444 = 0,
    Y_U_V422 = 1,
    Y_U_V420 = 2,
    Y_UV420 = 100,
    YUYV422 = 200,
    Y400 = 300,
}

Supported chroma subsampling input formats.

We use YUV/YCbCr/YPbPr interchangeably and usually just call it YUV.

According to this source:

• YUV is an analog signal
• YCbCr is scaled and offsetted version of YUV, used in digital signals (we denote this as “limited range YUV”)
• YPbPr is the physical component cabel to transmit YCbCr Actual use in the wild seems to be all over the place. For instance OpenCV uses YCbCr when talking about the full range and YUV when talking about limited range. Source:

RGB <-> YCrCb JPEG […] Y, Cr, and Cb cover the whole value range. RGB <-> YUV with subsampling […] with resulting values Y [16, 235], U and V [16, 240] centered at 128.

For more on YUV ranges see YuvRange.

Naming schema:

• every time a plane starts add a _
• end with 4xy for 4:x:y subsampling.

This picture gives a great overview of how to interpret the 4:x:y naming scheme for subsampling: https://en.wikipedia.org/wiki/Chroma_subsampling#Sampling_systems_and_ratios/

Keep indices in sync with yuv_converter.wgsl

Variants

Y_U_V444 = 0

4:4:4 no chroma downsampling with 3 separate planes. Also known as I444

Expects single channel data texture format.

           width
         __________
         |         |
height   |    Y    |
         |         |
         |_________|
         |         |
height   |    U    |
         |         |
         |_________|
         |         |
height   |    V    |
         |         |
         |_________|

Y_U_V422 = 1

4:2:2 subsampling with 3 separate planes. Also known as I422

Expects single channel data texture format.

Each data texture row in U & V section contains two rows of U/V respectively, since there’s a total of (width/2) * (height/2) U & V samples

           width
         __________
         |         |
height   |    Y    |
         |         |
         |_________|
height/2 |    U    |
         |_________|
height/2 |    V    |
         |_________|

Y_U_V420 = 2

4:2:0 subsampling with 3 separate planes. Also known as I420

Expects single channel data texture format.

Each data texture row in U & V section contains two rows of U/V respectively, since there’s a total of (width/2) * height U & V samples

           width
         __________
         |         |
height   |    Y    |
         |         |
         |_________|
height/4 |___◌̲U____|
height/4 |___◌̲V____|

Y_UV420 = 100

4:2:0 subsampling with a separate Y plane, followed by a UV plane. Also known as NV12 (although NV12 usually also implies the limited range).

Expects single channel data texture format.

First comes entire image in Y in one plane, followed by a plane with interleaved lines ordered as U0, V0, U1, V1, etc.

         width
         __________
         |         |
height   |    Y    |
         |         |
         |_________|
height/2 | U,V,U,… |
         |_________|

YUYV422 = 200

YUV 4:2:2 subsampling, single plane.

Expects single channel data texture format.

The order of the channels is Y0, U0, Y1, V0, all in the same plane.

            width * 2
       __________________
       |                 |
height | Y0, U0, Y1, V0… |
       |_________________|

Y400 = 300

4:0:0, single plane of chroma only. Also known as I400

Expects single channel data texture format.

Note that we still convert this to RGBA, for convenience.

            width
         __________
         |         |
height   |    Y    |
         |         |
         |_________|

Implementations

impl YuvPixelLayout

pub fn data_texture_width_height( &self, [decoded_width, decoded_height]: [u32; 2] ) -> [u32; 2]

Given the dimensions of the output picture, what are the expected dimensions of the input data texture.

pub fn data_texture_format(&self) -> TextureFormat

What format the input data texture is expected to be in.

pub fn num_data_buffer_bytes(&self, decoded_width: [u32; 2]) -> usize

Size of the buffer needed to create the data texture, i.e. the raw input data.

Trait Implementations

impl Clone for YuvPixelLayout

fn clone(&self) -> YuvPixelLayout

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for YuvPixelLayout

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for YuvPixelLayout

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Copy for YuvPixelLayout