Class ov::op::v8::I420toRGB

class I420toRGB : public ov::op::util::ConvertColorI420Base

Color conversion operation from I420 to RGB format. Input:

  • Input NV12 image can be represented in two ways: a) Single plane (as it is in the file): I420 height dimension is 1.5x bigger than image height. ‘C’ dimension shall be 1. b) Three separate planes (used this way in many physical video sources): Y, U and V. In this case b1) Y plane has height same as image height. ‘C’ dimension equals to 1 b2) U plane has dimensions: ‘H’ = image_h / 2; ‘W’ = image_w / 2; ‘C’ = 1. b3) V plane has dimensions: ‘H’ = image_h / 2; ‘W’ = image_w / 2; ‘C’ = 1.

  • Supported element types: u8 or any supported floating-point type. Output:

  • Output node will have NHWC layout and shape HxW same as image spatial dimensions.

  • Number of output channels ‘C’ will be 3, as per interleaved RGB format, first channel is R, last is B

    Conversion of each pixel from I420 (YUV) to RGB space is represented by following formulas: R = 1.164 * (Y - 16) + 1.596 * (V - 128) G = 1.164 * (Y - 16) - 0.813 * (V - 128) - 0.391 * (U - 128) B = 1.164 * (Y - 16) + 2.018 * (U - 128) Then R, G, B values are clipped to range (0, 255)

Public Functions

explicit I420toRGB(const Output<Node> &arg)

Constructs a conversion operation from input image in I420 format As per I420 format definition, node height dimension shall be 1.5 times bigger than image height so that image (w=640, h=480) is represented by NHWC shape {N,720,640,1} (height*1.5 x width)

Parameters

arg – Node that produces the input tensor. Input tensor represents image in NV12 format (YUV).

explicit I420toRGB(const Output<Node> &arg_y, const Output<Node> &arg_u, const Output<Node> &arg_v)

Constructs a conversion operation from 2-plane input image in NV12 format In general case Y channel of image can be separated from UV channel which means that operation needs two nodes for Y and UV planes respectively. Y plane has one channel, and UV has 2 channels, both expect ‘NHWC’ layout.

Parameters

  • arg_y – Node that produces the input tensor for Y plane (NHWC layout). Shall have WxH dimensions equal to image dimensions. ‘C’ dimension equals to 1.

  • arg_u – Node that produces the input tensor for U plane (NHWC layout). ‘H’ is half of image height, ‘W’ is half of image width, ‘C’ dimension equals to 1.

  • arg_v – Node that produces the input tensor for V plane (NHWC layout). ‘H’ is half of image height, ‘W’ is half of image width, ‘C’ dimension equals to 1.