more renaming

modules/v4d/tutorials/00-intro.markdown

@@ -45,10 +45,10 @@ Please note that the following online demos are slower and/or have less features
 For example, to create an OpenGL context and set the GL viewport:
 @code{.cpp}
 //Creates a V4D object for on screen rendering
-Ptr<V4D> v2d = V4D::make(Size(WIDTH, HEIGHT), "GL viewport");
+Ptr<V4D> v4d = V4D::make(Size(WIDTH, HEIGHT), "GL viewport");
 
 //Takes care of OpenGL states in the background
-v2d->gl([](const Size sz) {
+v4d->gl([](const Size sz) {
     glViewPort(0, 0, sz.width, sz.height);
 });
 @endcode

modules/v4d/tutorials/05-video_editing.markdown

@@ -9,7 +9,7 @@
 | Compatibility | OpenCV >= 4.7 |
 
 ## Render text on top of a video
-Through adding a Source and a Sink v2d becomes capable of video editing. Reads a video, renders text on top and writes the result. Note: Reading and writing of video-data is multi-threaded in the background for performance reasons.
+Through adding a Source and a Sink v4d becomes capable of video editing. Reads a video, renders text on top and writes the result. Note: Reading and writing of video-data is multi-threaded in the background for performance reasons.
 
 @include samples/cpp/video_editing.cpp