Miscolored picture during multiple video rendering - c++

Question

I am currently working on rendering two different video streams at the same time to two different OpenGL textures. I use an implementation of QAbstractVideoSurface to prepare each frame of the video and then I pass it to my OpenGL draw method. Each frame arrives in YUV coding so in order to get the RGB values I use GLSL.
The problem is the following: every time I try to draw more than one of these videos the first one plays correctly but the other does some kinkiness with the channels.
My vertex shader:
#version 420
attribute vec2 position;
attribute vec2 texcoord;
uniform mat4 modelViewProjectionMatrix;
varying vec2 v_texcoord;
void main()
{
gl_Position = modelViewProjectionMatrix * vec4(position, 0, 1);
v_texcoord = texcoord.xy;
}
My fragment shader:
#version 420
varying vec2 v_texcoord;
uniform sampler2D s_texture_y;
uniform sampler2D s_texture_u;
uniform sampler2D s_texture_v;
uniform float s_texture_alpha;
void main(void)
{
highp float y = texture2D(s_texture_y, v_texcoord).r;
highp float u = texture2D(s_texture_u, v_texcoord).r - 0.5;
highp float v = texture2D(s_texture_v, v_texcoord).r - 0.5;
highp float r = y + 1.402 * v;
highp float g = y - 0.344 * u - 0.714 * v;
highp float b = y + 1.772 * u;
gl_FragColor = vec4(r, g, b, s_texture_alpha);
}
The result is like the following picture:
Sometimes it gets it right, sometimes it's even worse, but the first video plays correctly all the time.
After fooling around a bit with the channels I found out that sometimes the u variable gets the same value as v in the fragment shader. My texture bindig is as it follows:
uniformSamplers[0] = functions.glGetUniformLocation(program, "s_texture_y");
uniformSamplers[1] = functions.glGetUniformLocation(program, "s_texture_u");
uniformSamplers[2] = functions.glGetUniformLocation(program, "s_texture_v");
glActiveTexture(GL_TEXTURE0 + 0);
glBindTexture(GL_TEXTURE_2D, textRef);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, image_width, image_height, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, (GLvoid*)(image));
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
functions.glUniform1i(uniformSamplers[0], 0);
glActiveTexture(GL_TEXTURE0 + 1);
glBindTexture(GL_TEXTURE_2D, textRefU);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, image_width / 2, image_height / 2, 0, GL_LUMINANCE,
GL_UNSIGNED_BYTE, (GLvoid*)(image + image_width * image_height));
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
functions.glUniform1i(uniformSamplers[1], 1);
glActiveTexture(GL_TEXTURE0 + 2);
glBindTexture(GL_TEXTURE_2D, textRefV);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, image_width / 2, image_height / 2, 0, GL_LUMINANCE,
GL_UNSIGNED_BYTE, (GLvoid*)(image + image_height * image_width + (image_width / 2) * (image_height / 2)));
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
functions.glUniform1i(uniformSamplers[2], 2);

Answer 1

The problem was quite lame, I focused on the shaders and spent several days trying to find out the problem there. However the problem was in the texture reference intialization. All three references had the same value, thus I overwrote the same texture each time. With having all three on different value it works perfectly.