NSOpenGL I420 YUV buffer render on OSX

Question

In my application, i have to display the YUV frame receiving from the server, YUV image format is I420,

I have subclass NSOpenGLView like this,

@interface RTCNSGLVideoView : NSOpenGLView <RTCVideoRenderer>

and OpenGL View creating on the View something like this,

if ( bUsingOpenGL && !pVideoRTCGLView){
    NSOpenGLPixelFormatAttribute attributes[] = {
        NSOpenGLPFADoubleBuffer,
        NSOpenGLPFADepthSize, 24,
        NSOpenGLPFAOpenGLProfile,
        NSOpenGLProfileVersion3_2Core,
        0
    };
    NSRect frameRect = [pImageView frame];



    NSOpenGLPixelFormat* pixelFormat =
    [[NSOpenGLPixelFormat alloc] initWithAttributes:attributes];
    pVideoRTCGLView = [[RTCNSGLVideoView alloc] initWithFrame:frameRect
                                                   pixelFormat:pixelFormat];
    [pVideoRTCGLView setAutoresizingMask:[pImageView autoresizingMask]];
    [pVideoRTCGLView setTranslatesAutoresizingMaskIntoConstraints:NO];
    [pVideoRTCGLView setYUVFrameDelegate:self];
    [[[self window] contentView] addSubview:pVideoRTCGLView];
    [pVideoRTCGLView prepareOpenGL];
}

I am displaying I420 directly on the screen, and for that, Vertex and shaders program are like this,

#define RTC_PIXEL_FORMAT GL_RED
#define SHADER_VERSION "#version 150\n"
#define VERTEX_SHADER_IN "in"
#define VERTEX_SHADER_OUT "out"
#define FRAGMENT_SHADER_IN "in"
#define FRAGMENT_SHADER_OUT "out vec4 fragColor;\n"
#define FRAGMENT_SHADER_COLOR "fragColor"
#define FRAGMENT_SHADER_TEXTURE "texture"
#endif

// Vertex shader doesn't do anything except pass coordinates through.
static const char kVertexShaderSource[] =
  SHADER_VERSION
  VERTEX_SHADER_IN " vec2 position;\n"
  VERTEX_SHADER_IN " vec2 texcoord;\n"
  VERTEX_SHADER_OUT " vec2 v_texcoord;\n"
  "void main() {\n"
  "    gl_Position = vec4(position.x, position.y, 0.0, 1.0);\n"
  "    v_texcoord = texcoord;\n"
  "}\n";

// Fragment shader converts YUV values from input textures into a final RGB
// pixel. The conversion formula is from http://www.fourcc.org/fccyvrgb.php.
static const char kFragmentShaderSource[] =
  SHADER_VERSION
  "precision highp float;"
  FRAGMENT_SHADER_IN " vec2 v_texcoord;\n"
  "uniform lowp sampler2D s_textureY;\n"
  "uniform lowp sampler2D s_textureU;\n"
  "uniform lowp sampler2D s_textureV;\n"
  FRAGMENT_SHADER_OUT
  "void main() {\n"
  "    float y, u, v, r, g, b;\n"
  "    y = " FRAGMENT_SHADER_TEXTURE "(s_textureY, v_texcoord).r;\n"
  "    u = " FRAGMENT_SHADER_TEXTURE "(s_textureU, v_texcoord).r;\n"
  "    v = " FRAGMENT_SHADER_TEXTURE "(s_textureV, v_texcoord).r;\n"
  "    u = u - 0.5;\n"
  "    v = v - 0.5;\n"
  "    r = y + 1.403 * v;\n"
  "    g = y - 0.344 * u - 0.714 * v;\n"
  "    b = y + 1.770 * u;\n"
  "    " FRAGMENT_SHADER_COLOR " = vec4(r, g, b, 1.0);\n"
  "  }\n";

// Compiles a shader of the given |type| with GLSL source |source| and returns
// the shader handle or 0 on error.
GLuint CreateShader(GLenum type, const GLchar* source) {
  GLuint shader = glCreateShader(type);
  if (!shader) {
    return 0;
  }
  glShaderSource(shader, 1, &source, NULL);
  glCompileShader(shader);
  GLint compileStatus = GL_FALSE;
  glGetShaderiv(shader, GL_COMPILE_STATUS, &compileStatus);
  if (compileStatus == GL_FALSE) {
    glDeleteShader(shader);
    shader = 0;
  }
  return shader;
}

// Links a shader program with the given vertex and fragment shaders and
// returns the program handle or 0 on error.
GLuint CreateProgram(GLuint vertexShader, GLuint fragmentShader) {
  if (vertexShader == 0 || fragmentShader == 0) {
    return 0;
  }
  GLuint program = glCreateProgram();
  if (!program) {
    return 0;
  }
  glAttachShader(program, vertexShader);
  glAttachShader(program, fragmentShader);
  glLinkProgram(program);
  GLint linkStatus = GL_FALSE;
  glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
  if (linkStatus == GL_FALSE) {
    glDeleteProgram(program);
    program = 0;
  }
  return program;
}

In the Subclass view, i am setting the view port size like this,

- (void)reshape {
  [super reshape];
  NSRect frame = [self frame];
    NSLog(@"reshaping viewport (%@) ",NSStringFromRect(frame));
  CGLLockContext([[self openGLContext] CGLContextObj]);
  glViewport(0, 0, frame.size.width, frame.size.height);
  CGLUnlockContext([[self openGLContext] CGLContextObj]);
}

What i am seeing is bottom and right side is bit corrupted, please refer the image,

Please help me, not able to figure it out, what is going wrong,

if you refer the image, where i drawn Red rectangle at the bottom and on the right side this is coming unnecessary