TDA2HG: How to configure OpenGL YUV2RGB coef matrix

We use libEGL.so to convert YUV2RGB. And my code below:

  EGLint attr[32];
  int attrIdx;
  attrIdx = 0;

  attr[attrIdx++] = EGL_LINUX_DRM_FOURCC_EXT;
  attr[attrIdx++] = FOURCC_STR("NV12");

  attr[attrIdx++] = EGL_WIDTH;
  attr[attrIdx++] = width;

  attr[attrIdx++] = EGL_HEIGHT;
  attr[attrIdx++] = height;

  attr[attrIdx++] = EGL_DMA_BUF_PLANE0_PITCH_EXT;
  attr[attrIdx++] = width;

  attr[attrIdx++] = EGL_DMA_BUF_PLANE1_PITCH_EXT;
  attr[attrIdx++] = width;

  attr[attrIdx++] = EGL_DMA_BUF_PLANE0_OFFSET_EXT;
  attr[attrIdx++] = 0;

  attr[attrIdx++] = EGL_DMA_BUF_PLANE1_OFFSET_EXT;
  attr[attrIdx++] = 0;

  attr[attrIdx++] = EGL_DMA_BUF_PLANE0_FD_EXT;
  attr[attrIdx++] = dmaBufFd;

  attr[attrIdx++] = EGL_DMA_BUF_PLANE1_FD_EXT;
  attr[attrIdx++] = dmaBufFd;
  
  attr[attrIdx++] = EGL_YUV_COLOR_SPACE_HINT_EXT;
  attr[attrIdx++] = EGL_ITU_REC601_EXT;                 // set convert as BT601

  attr[attrIdx++] = EGL_NONE;
  
  EGLImageKHR textureImg = eglCreateImageKHR(
      NativeEGLDisplay,
      EGL_NO_CONTEXT,
      EGL_LINUX_DMA_BUF_EXT,
      NULL,
      attr);

Hi Tim,

A part of the team that can help with this is currently out of office.

We will try to prioritize this early next week. Thanks for your understanding.

Regards

Karthik

Thanks Karthik.

Dear Customer.

Can we get more details on the use case? you should be able to use a shader to use any coefficients they want.

thank you!

yong

Dear Customer,

one more question, Do you want to change the coefficients for just one case or for every conversion?

thank you!

yong

Hi yong,

We want change the coefficients for just one case. And now we will trying to use a shader and set coefficients as you suggest. Any update I will let you know.

Thanks!

BR/Tim

Hi yong,

we have tried use shader to do YUV NV12 to RGB conversion but still found the same overexpose problem.

the coefficients we use:

the YUV2RGB shader: 

precision mediump float;

uniform sampler2D  fsSampler;   // Y plane
uniform sampler2D  fsSampler1;  // UV plane

varying vec2 vTexcoord;

vec3 yuv2rgb(vec3 yuv)
{
    float r, g, b;

#define DIGITAL_YUV_601
#ifdef DIGITAL_YUV_601
    const float rangeY = 16.0 / 255.0;
    const float rangeU = 128.0 / 255.0;
    const float rangeV = 128.0 / 255.0;
    const vec3 yuv2r = vec3(1.164, 0.0, 1.596);
    const vec3 yuv2g = vec3(1.164, -0.392, -0.812);
    const vec3 yuv2b = vec3(1.164, 2.016, 0.0);
    const vec3 range = vec3(rangeY, rangeU, rangeV);
#else  // Analog
    const vec3 yuv2r = vec3(1.0, 0.0, 1.402);
    const vec3 yuv2g = vec3(1.0, -0.344, -0.792);
    const vec3 yuv2b = vec3(1.0, 1.772, 0.0);
    const vec3 range = vec3(0.0, 0.0, 0.0);
#endif

    yuv = yuv - range;
    r = dot(yuv, yuv2r);
    g = dot(yuv, yuv2g);
    b = dot(yuv, yuv2b);
    return vec3(r, g, b);
}

void main (void)
{
    vec3 yuv = vec3(texture2D(fsSampler, vTexcoord).r, // Y
                    texture2D(fsSampler1, vTexcoord).r, // U
                    texture2D(fsSampler1, vTexcoord).a); // V
    gl_FragColor = vec4(yuv2rgb(yuv), 1.0);
}

Thanks!

hi Wei.

would you please show the result when you said "still found the same overexpose problem"? thank you!

yong

Hi yong,

I attached picture below:

Picture from camera:

Picture after YUV2RGB which use default coefficients:

Picture after YUV2RGB which use shader code:

BR/Tim