diff --git a/CMakeLists.txt b/CMakeLists.txt
index 278f7f4..3add2b9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -238,7 +238,9 @@ set(VMIX_RSC_FILES
     ./rsc/fonts/Roboto-Italic.ttf
     ./rsc/fonts/fa-regular-400.ttf
     ./rsc/fonts/fa-solid-900.ttf
+    ./rsc/images/mask_vignette.png
     ./rsc/images/v-mix_256x256.png
+    ./rsc/images/rgb.png
     ./rsc/images/busy.png
     ./rsc/images/icons.dds
     ./rsc/images/seed_512.jpg
diff --git a/FrameBuffer.h b/FrameBuffer.h
index 858db32..250fdd0 100644
--- a/FrameBuffer.h
+++ b/FrameBuffer.h
@@ -12,19 +12,26 @@ public:
 
     // bind the FrameBuffer as current to draw into
     void bind();
-    void begin();
-    void end();
-
-    // release any framebuffer object
+    // unbind any framebuffer object
     static void release();
+    // Bind & push attribs to prepare draw
+    void begin();
+    // pop attrib and unbind to end draw
+    void end();
 
     // blit copy to another, returns true on success
     bool blit(FrameBuffer *other);
 
+    // clear color
+    inline void setClearColor(glm::vec3 color) { attrib_.clear_color = color; }
+    inline glm::vec3 clearColor() const { return attrib_.clear_color; }
+
+    // width & height
     inline uint width() const { return attrib_.viewport.x; }
     inline uint height() const { return attrib_.viewport.y; }
-    uint texture() const;
     float aspectRatio() const;
+    // texture index for draw
+    uint texture() const;
 
 private:
     void init();
diff --git a/ImGuiVisitor.cpp b/ImGuiVisitor.cpp
index 4d7ead7..65d4505 100644
--- a/ImGuiVisitor.cpp
+++ b/ImGuiVisitor.cpp
@@ -133,21 +133,7 @@ void ImGuiVisitor::visit(Shader &n)
 
 void ImGuiVisitor::visit(ImageShader &n)
 {
-    ImGui::PushID(n.id());
 
-    if (ImGuiToolkit::ButtonIcon(4, 1)) {
-        n.brightness = 0.f;
-        n.contrast = 0.f;
-    }
-    ImGui::SameLine(0, 10);
-    ImGui::SetNextItemWidth(RIGHT_ALIGN);
-    float bc[2] = { n.brightness, n.contrast};
-    if ( ImGui::SliderFloat2("B & C", bc, -1.0, 1.0) )
-    {
-        n.brightness = bc[0];
-        n.contrast = bc[1];
-    }
-    ImGui::PopID();
 }
 
 void ImGuiVisitor::visit(ImageProcessingShader &n)
diff --git a/ImageProcessingShader.cpp b/ImageProcessingShader.cpp
index 0ec345f..c800925 100644
--- a/ImageProcessingShader.cpp
+++ b/ImageProcessingShader.cpp
@@ -15,8 +15,8 @@ void ImageProcessingShader::use()
 {
     Shader::use();
 
-    program_->setUniform("iChannelResolution[0]", iChannelResolution[0].x, iChannelResolution[0].y, iChannelResolution[0].z);
-    program_->setUniform("iChannelResolution[1]", iChannelResolution[1].x, iChannelResolution[1].y, iChannelResolution[1].z);
+//    program_->setUniform("iChannelResolution[0]", iChannelResolution[0].x, iChannelResolution[0].y, iChannelResolution[0].z);
+//    program_->setUniform("iChannelResolution[1]", iChannelResolution[1].x, iChannelResolution[1].y, iChannelResolution[1].z);
 
     program_->setUniform("brightness", brightness);
     program_->setUniform("contrast", contrast);
@@ -41,9 +41,9 @@ void ImageProcessingShader::reset()
 {
     Shader::reset();
 
-    // no texture resolution yet
-    iChannelResolution[0] = glm::vec3(1.f);
-    iChannelResolution[1] = glm::vec3(1.f);
+//    // no texture resolution yet
+//    iChannelResolution[0] = glm::vec3(1.f);
+//    iChannelResolution[1] = glm::vec3(1.f);
 
     // default values for image processing
     brightness = 0.f;
@@ -63,6 +63,6 @@ void ImageProcessingShader::reset()
 }
 
 void ImageProcessingShader::accept(Visitor& v) {
-    Shader::accept(v);
+//    Shader::accept(v);
     v.visit(*this);
 }
diff --git a/ImageProcessingShader.h b/ImageProcessingShader.h
index 9567338..6fbb316 100644
--- a/ImageProcessingShader.h
+++ b/ImageProcessingShader.h
@@ -12,12 +12,12 @@ public:
     ImageProcessingShader();
     virtual ~ImageProcessingShader() {}
 
-    virtual void use();
-    virtual void reset();
-    virtual void accept(Visitor& v);
+    void use() override;
+    void reset() override;
+    void accept(Visitor& v) override;
 
-    // textures resolution
-    glm::vec3 iChannelResolution[2];
+//    // textures resolution
+//    glm::vec3 iChannelResolution[2];
 
     // color effects
     float brightness; // [-1 1]
diff --git a/ImageShader.cpp b/ImageShader.cpp
index e39e95d..f454ce5 100644
--- a/ImageShader.cpp
+++ b/ImageShader.cpp
@@ -1,6 +1,9 @@
+#include <glad/glad.h>
+
 #include "defines.h"
 #include "Visitor.h"
 #include "ImageShader.h"
+#include "Resource.h"
 
 ShadingProgram imageShadingProgram("shaders/image.vs", "shaders/image.fs");
 
@@ -14,9 +17,12 @@ void ImageShader::use()
 {
     Shader::use();
 
-    program_->setUniform("brightness", brightness);
-    program_->setUniform("contrast", contrast);
     program_->setUniform("stipple", stipple);
+
+    glActiveTexture(GL_TEXTURE1);
+    glBindTexture(GL_TEXTURE_2D, mask);
+    glActiveTexture(GL_TEXTURE0);
+
 }
 
 
@@ -24,8 +30,16 @@ void ImageShader::reset()
 {
     Shader::reset();
 
-    brightness = 0.f;
-    contrast = 0.f;
+    // setup double texturing
+    program_->use();
+    program_->setUniform("iChannel0", 0);
+    program_->setUniform("iChannel1", 1);
+    program_->enduse();
+
+    // default mask (channel1)
+    mask = Resource::getTextureWhite();
+
+    // no stippling
     stipple = 0.f;
 }
 
diff --git a/ImageShader.h b/ImageShader.h
index b445304..a9df308 100644
--- a/ImageShader.h
+++ b/ImageShader.h
@@ -10,12 +10,11 @@ public:
     ImageShader();
     virtual ~ImageShader() {}
 
-    virtual void use();
-    virtual void reset();
-    virtual void accept(Visitor& v);
+    void use() override;
+    void reset() override;
+    void accept(Visitor& v) override;
 
-    float brightness;
-    float contrast;
+    uint mask;
     float stipple;
 };
 
diff --git a/MediaPlayer.cpp b/MediaPlayer.cpp
index 52b256e..89a3ea2 100644
--- a/MediaPlayer.cpp
+++ b/MediaPlayer.cpp
@@ -296,14 +296,14 @@ void MediaPlayer::play(bool on)
         timecount_.reset();
 }
 
-bool MediaPlayer::isPlaying() const
+bool MediaPlayer::isPlaying(bool testpipeline) const
 {
     // image cannot play
     if (isimage_)
         return false;
 
     // if not ready yet, answer with requested state
-    if ( pipeline_ == nullptr )
+    if ( !testpipeline || pipeline_ == nullptr )
         return desired_state_ == GST_STATE_PLAYING;
 
     // if ready, answer with actual state
diff --git a/MediaPlayer.h b/MediaPlayer.h
index 5e17087..141e3be 100644
--- a/MediaPlayer.h
+++ b/MediaPlayer.h
@@ -123,7 +123,7 @@ public:
     /**
      * Get Pause / Play
      * */
-    bool isPlaying() const;
+    bool isPlaying(bool testpipeline = false) const;
     /**
      * Speed factor for playing
      * Can be negative.
diff --git a/Resource.cpp b/Resource.cpp
index 2842c6f..c63a1fc 100644
--- a/Resource.cpp
+++ b/Resource.cpp
@@ -29,11 +29,11 @@ uint Resource::getTextureBlack()
 {
     static uint tex_index_black = 0;
 
-    // generate texture (once) & clear
+    // generate texture (once)
     if (tex_index_black == 0) {
         glGenTextures(1, &tex_index_black);
         glBindTexture( GL_TEXTURE_2D, tex_index_black);
-        unsigned char clearColor[4] = {0};
+        unsigned char clearColor[4] = {0, 0, 0, 0};
         // texture with one black pixel
         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, clearColor);
     }
@@ -41,6 +41,22 @@ uint Resource::getTextureBlack()
     return tex_index_black;
 }
 
+uint Resource::getTextureWhite()
+{
+    static uint tex_index_white = 0;
+
+    // generate texture (once)
+    if (tex_index_white == 0) {
+        glGenTextures(1, &tex_index_white);
+        glBindTexture( GL_TEXTURE_2D, tex_index_white);
+        unsigned char clearColor[4] = {255, 255, 255, 255};
+        // texture with one black pixel
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, clearColor);
+    }
+
+    return tex_index_white;
+}
+
 const char *Resource::getData(const std::string& path, size_t* out_file_size){
 
     auto  fs = cmrc::vmix::get_filesystem();
diff --git a/Resource.h b/Resource.h
index 5c8b17c..9a6929d 100644
--- a/Resource.h
+++ b/Resource.h
@@ -22,9 +22,12 @@ namespace Resource
     // Returns the OpenGL generated Texture index
     uint getTextureImage(const std::string& path, float *aspect_ratio = nullptr);
 
-    // Returns the OpenGL generated Texture index for an empty 1x1 black pixel texture
+    // Returns the OpenGL generated Texture index for an empty 1x1 black transparent pixel texture
     uint getTextureBlack();
 
+    // Returns the OpenGL generated Texture index for an empty 1x1 white opaque pixel texture
+    uint getTextureWhite();
+
     // Generic access to pointer to data
     const char *getData(const std::string& path, size_t* out_file_size);
 
diff --git a/SessionVisitor.cpp b/SessionVisitor.cpp
index a957c0e..bf6aca7 100644
--- a/SessionVisitor.cpp
+++ b/SessionVisitor.cpp
@@ -159,8 +159,6 @@ void SessionVisitor::visit(ImageShader &n)
     xmlCurrent_->SetAttribute("type", "ImageShader");
 
     XMLElement *filter = xmlDoc_->NewElement("uniforms");
-    filter->SetAttribute("brightness", n.brightness);
-    filter->SetAttribute("contrast", n.contrast);
     filter->SetAttribute("stipple", n.stipple);
     xmlCurrent_->InsertEndChild(filter);
 
diff --git a/Source.cpp b/Source.cpp
index ef47ae9..d5426e6 100644
--- a/Source.cpp
+++ b/Source.cpp
@@ -33,10 +33,13 @@ Source::Source(std::string name) : name_(""), initialized_(false)
     Frame *frame = new Frame(Frame::MIXING);
     frame->translation_.z = 0.1;
     groups_[View::MIXING]->addChild(frame);
-    groups_[View::MIXING]->scale_ = glm::vec3(0.2f, 0.2f, 1.f);
+    groups_[View::MIXING]->scale_ = glm::vec3(0.15f, 0.15f, 1.f);
 
     // will be associated to nodes later
+    mixingshader_ = new ImageShader();
     rendershader_ = new ImageProcessingShader();
+    renderbuffer_ = nullptr;
+    rendersurface_ = nullptr;
 
     // add source to the list
     sources_.push_front(this);
@@ -44,8 +47,10 @@ Source::Source(std::string name) : name_(""), initialized_(false)
 
 Source::~Source()
 {
-    // delete shader
+    // delete render objects
     delete rendershader_;
+    if (renderbuffer_)
+        delete renderbuffer_;
 
     // delete groups and their children
     delete groups_[View::RENDERING];
@@ -137,7 +142,7 @@ MediaSource::MediaSource(std::string name, std::string uri) : Source(name), uri_
     // - textured with original texture from media player
     // - crop & repeat UV can be managed here
     // - additional custom shader can be associated
-    mediasurface_ = new Surface;
+    mediasurface_ = new Surface(rendershader_);
 
     // extra overlay for mixing view
     mixingoverlay_ = new Frame(Frame::MIXING_OVERLAY);
@@ -180,18 +185,17 @@ void MediaSource::init()
             // create Frame buffer matching size of media player
             renderbuffer_ = new FrameBuffer(mediaplayer()->width(), mediaplayer()->height());
 
-            // setup shader resolution for texture 0
-            rendershader_->iChannelResolution[0] = glm::vec3(mediaplayer()->width(), mediaplayer()->height(), 0.f);
+//            // setup shader resolution for texture 0
+//            rendershader_->iChannelResolution[0] = glm::vec3(mediaplayer()->width(), mediaplayer()->height(), 0.f);
 
             // create the surfaces to draw the frame buffer in the views
             // TODO Provide the source specific effect shader
-            rendersurface_ = new FrameBufferSurface(renderbuffer_, rendershader_);
+            rendersurface_ = new FrameBufferSurface(renderbuffer_, mixingshader_);
             groups_[View::RENDERING]->addChild(rendersurface_);
             groups_[View::MIXING]->addChild(rendersurface_);
 
             // for mixing view, add another surface to overlay (for stippled view in transparency)
-            Surface *surfacemix = new Surface();
-            surfacemix->setTextureIndex( mediaplayer_->texture() );
+            Surface *surfacemix = new FrameBufferSurface(renderbuffer_);
             ImageShader *is = static_cast<ImageShader *>(surfacemix->shader());
             if (is)  is->stipple = 1.0;
             groups_[View::MIXING]->addChild(surfacemix);
@@ -202,6 +206,8 @@ void MediaSource::init()
                 (*node)->scale_.x = mediaplayer_->aspectRatio();
             }
 
+//            mixingshader_->mask = Resource::getTextureImage("images/mask_vignette.png");
+
             // done init once and for all
             initialized_ = true;
         }
@@ -223,15 +229,24 @@ void MediaSource::render(bool current)
         mediasurface_->draw(glm::identity<glm::mat4>(), projection);
         renderbuffer_->end();
 
-
         // read position of the mixing node and interpret this as transparency of render output
         float alpha = 1.0 - CLAMP( SQUARE( glm::length(groups_[View::MIXING]->translation_) ), 0.f, 1.f );
-        rendershader_->color.a = alpha;
-
+        mixingshader_->color.a = alpha;
 
         // make Mixing Overlay visible if it is current source
         mixingoverlay_->visible_ = current;
     }
 }
 
+FrameBuffer *MediaSource::frame() const
+{
+    if (initialized_ && renderbuffer_)
+    {
+        return renderbuffer_;
+    }
+    else {
+        static FrameBuffer *black = new FrameBuffer(640,480);
+        return black;
+    }
 
+}
diff --git a/Source.h b/Source.h
index ce8c460..e3e541c 100644
--- a/Source.h
+++ b/Source.h
@@ -7,11 +7,12 @@
 
 #include "View.h"
 
+class ImageShader;
 class ImageProcessingShader;
-class Surface;
 class FrameBuffer;
-class MediaPlayer;
 class FrameBufferSurface;
+class MediaPlayer;
+class Surface;
 class Frame;
 
 class Source;
@@ -34,8 +35,14 @@ public:
     // get handle on the node used to manipulate the source in a view
     inline Group *group(View::Mode m) const { return groups_.at(m); }
 
-    // every Source have a shader to control visual effects
-    inline ImageProcessingShader *shader() const { return rendershader_; }
+    // every Source has a shader to control image processing effects
+    inline ImageProcessingShader *processingShader() const { return rendershader_; }
+
+    // every Source has a shader to control mixing effects
+    inline ImageShader *mixingShader() const { return mixingshader_; }
+
+    // every Source shall have a frame buffer
+    virtual FrameBuffer *frame() const = 0;
 
     // every Source shall be rendered before draw
     virtual void render(bool current) = 0;
@@ -60,18 +67,21 @@ protected:
     std::map<View::Mode, Group*> groups_;
 
     // render() fills in the renderbuffer at every frame
-    // NB: additional shader (custom) are applied inside render()
+    // NB: rendershader_ is applied at render()
     FrameBuffer *renderbuffer_;
 
     // the rendersurface draws the renderbuffer in the scene
     // It is associated to the rendershader for mixing effects
-    // (aka visual effect applied in scene, not in render() )
     FrameBufferSurface *rendersurface_;
 
-    // rendershader provides all image processing controls for
-    // mixing sources in the scene
+    // rendershader provides image processing controls
     ImageProcessingShader *rendershader_;
 
+    // mixingshader provides mixing controls
+    ImageShader *mixingshader_;
+
+    Frame *mixingoverlay_;
+
     // static global list of sources
     static SourceList sources_;
 };
@@ -103,6 +113,8 @@ public:
     MediaSource(std::string name, std::string uri);
     ~MediaSource();
 
+    FrameBuffer *frame() const;
+    ImageShader *mixingShader() const;
     void render(bool current);
 
     // Media specific interface
@@ -113,7 +125,6 @@ protected:
 
     virtual void init();
 
-    Frame *mixingoverlay_;
     Surface *mediasurface_;
     std::string uri_;
     MediaPlayer *mediaplayer_;
diff --git a/UserInterfaceManager.cpp b/UserInterfaceManager.cpp
index bf9d1be..b32a1dc 100644
--- a/UserInterfaceManager.cpp
+++ b/UserInterfaceManager.cpp
@@ -40,6 +40,8 @@
 #include "ImGuiToolkit.h"
 #include "GstToolkit.h"
 #include "Mixer.h"
+#include "FrameBuffer.h"
+#include "MediaPlayer.h"
 #include "PickingVisitor.h"
 
 static std::thread loadThread;
@@ -75,6 +77,8 @@ UserInterface::UserInterface()
 {
     currentFileDialog = "";
     currentTextEdit = "";
+    show_preview = true;
+    show_media_player = false;
 }
 
 bool UserInterface::Init()
@@ -265,7 +269,7 @@ void UserInterface::NewFrame()
 }
 
 void UserInterface::Render()
-{	
+{
     ImVec2 geometry(static_cast<float>(Rendering::manager().Width()), static_cast<float>(Rendering::manager().Height()));
 
     // file modal dialog
@@ -283,6 +287,12 @@ void UserInterface::Render()
     // warning modal dialog
     Log::Render();
 
+    // windows
+    if (show_preview)
+        RenderPreview();
+    if (show_media_player)
+        RenderMediaPlayer();
+
     // Rendering 
     ImGui::Render();
     ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
@@ -681,7 +691,6 @@ void MainWindow::Render()
     ImGui::SetNextWindowPos(ImVec2(40, 40), ImGuiCond_FirstUseEver);
     ImGui::SetNextWindowSize(ImVec2(300, 300), ImGuiCond_FirstUseEver);
 
-
     ImGui::Begin(IMGUI_TITLE_MAINWINDOW, NULL, ImGuiWindowFlags_MenuBar | ImGuiWindowFlags_NoCollapse);
 
     // Menu Bar
@@ -703,8 +712,12 @@ void MainWindow::Render()
             }
             ImGui::EndMenu();
         }
-        if (ImGui::BeginMenu("Appearance"))
+        if (ImGui::BeginMenu("Windows"))
         {
+            ImGui::MenuItem( IMGUI_TITLE_PREVIEW, NULL, &UserInterface::manager().show_preview);
+            ImGui::MenuItem( IMGUI_TITLE_MEDIAPLAYER, NULL, &UserInterface::manager().show_media_player);
+            ImGui::MenuItem( IMGUI_TITLE_SHADEREDITOR, NULL, &show_editor_window);
+            ImGui::MenuItem("Appearance", NULL, false, false);
             ImGui::SetNextItemWidth(200);
             if ( ImGui::SliderFloat("Scale", &Settings::application.scale, 0.8f, 1.2f, "%.1f"))
                 ImGui::GetIO().FontGlobalScale = Settings::application.scale;
@@ -716,7 +729,6 @@ void MainWindow::Render()
         }
         if (ImGui::BeginMenu("Tools"))
         {
-            ImGui::MenuItem( ICON_FA_CODE " Shader Editor", NULL, &show_editor_window);
             ImGui::MenuItem( ICON_FA_LIST "  Logs", "Ctrl+L", &show_logs_window);
             ImGui::MenuItem( ICON_FA_TACHOMETER_ALT " Metrics", NULL, &show_overlay_stats);
             if ( ImGui::MenuItem( ICON_FA_CAMERA_RETRO "  Screenshot", NULL) )
@@ -811,6 +823,136 @@ void MainWindow::Render()
     }
 }
 
+void UserInterface::RenderPreview()
+{
+    FrameBuffer *output = Mixer::manager().frame();
+    if (output)
+    {
+        ImGui::SetNextWindowPos(ImVec2(100, 300), ImGuiCond_FirstUseEver);
+        ImGui::SetNextWindowSize(ImVec2(640, 480), ImGuiCond_FirstUseEver);
+        ImGui::Begin(ICON_FA_LAPTOP " Preview", &show_preview,  ImGuiWindowFlags_NoScrollbar);
+        float width = ImGui::GetContentRegionAvail().x;
+
+        ImVec2 imagesize ( width, width / output->aspectRatio());
+        ImGui::Image((void*)(intptr_t)output->texture(), imagesize, ImVec2(0.f, 0.f), ImVec2(1.f, -1.f));
+
+        ImGui::End();
+    }
+}
+
+void UserInterface::RenderMediaPlayer()
+{
+    bool show = false;
+    MediaPlayer *mp = nullptr;
+    MediaSource *s = nullptr;
+    if ( Mixer::manager().currentSource()) {
+        s = static_cast<MediaSource *>(Mixer::manager().currentSource());
+        if (s) {
+            mp = s->mediaplayer();
+            if (mp && mp->isOpen())
+                show = true;
+        }
+    }
+
+    ImGui::SetNextWindowPos(ImVec2(200, 200), ImGuiCond_FirstUseEver);
+    ImGui::SetNextWindowSize(ImVec2(300, 300), ImGuiCond_FirstUseEver);
+
+    if ( !ImGui::Begin(IMGUI_TITLE_MEDIAPLAYER, &show_media_player,  ImGuiWindowFlags_NoScrollbar) || !show)
+    {
+        ImGui::End();
+        return;
+    }
+
+    float width = ImGui::GetContentRegionAvail().x;
+    float spacing = ImGui::GetStyle().ItemInnerSpacing.x;
+
+    ImVec2 imagesize ( width, width / mp->aspectRatio());
+    ImGui::Image((void*)(uintptr_t)mp->texture(), imagesize);
+    if (ImGui::IsItemHovered()) {
+        ImGui::SameLine(-1);
+        ImGui::Text("    %s %d x %d\n    Framerate %.2f / %.2f", mp->codec().c_str(), mp->width(), mp->height(), mp->updateFrameRate() , mp->frameRate() );
+    }
+
+    if (ImGui::Button(ICON_FA_FAST_BACKWARD))
+        mp->rewind();
+    ImGui::SameLine(0, spacing);
+
+    // remember playing mode of the GUI
+    bool media_playing_mode = mp->isPlaying();
+
+    // display buttons Play/Stop depending on current playing mode
+    if (media_playing_mode) {
+
+        if (ImGui::Button(ICON_FA_STOP " Stop"))
+            media_playing_mode = false;
+        ImGui::SameLine(0, spacing);
+
+        ImGui::PushButtonRepeat(true);
+         if (ImGui::Button(ICON_FA_FORWARD))
+            mp->fastForward ();
+        ImGui::PopButtonRepeat();
+    }
+    else {
+
+        if (ImGui::Button(ICON_FA_PLAY "  Play"))
+            media_playing_mode = true;
+        ImGui::SameLine(0, spacing);
+
+        ImGui::PushButtonRepeat(true);
+        if (ImGui::Button(ICON_FA_STEP_FORWARD))
+            mp->seekNextFrame();
+        ImGui::PopButtonRepeat();
+    }
+
+    ImGui::SameLine(0, spacing * 4.f);
+
+    static int current_loop = 0;
+    static std::vector< std::pair<int, int> > iconsloop = { {0,15}, {1,15}, {19,14} };
+    current_loop = (int) mp->loop();
+    if ( ImGuiToolkit::ButtonIconMultistate(iconsloop, &current_loop) )
+        mp->setLoop( (MediaPlayer::LoopMode) current_loop );
+
+    float speed = static_cast<float>(mp->playSpeed());
+    ImGui::SameLine(0, spacing);
+    ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x - 40.0);
+    // ImGui::SetNextItemWidth(width - 90.0);
+    if (ImGui::DragFloat( "##Speed", &speed, 0.01f, -10.f, 10.f, "Speed x %.1f", 2.f))
+        mp->setPlaySpeed( static_cast<double>(speed) );
+    ImGui::SameLine(0, spacing);
+    if (ImGuiToolkit::ButtonIcon(12, 14)) {
+        speed = 1.f;
+        mp->setPlaySpeed( static_cast<double>(speed) );
+        mp->setLoop( MediaPlayer::LOOP_REWIND );
+    }
+
+    guint64 current_t = mp->position();
+    guint64 seek_t = current_t;
+
+    bool slider_pressed = ImGuiToolkit::TimelineSlider( "simpletimeline", &seek_t,
+                                                        mp->duration(), mp->frameDuration());
+
+    // if the seek target time is different from the current position time
+    // (i.e. the difference is less than one frame)
+    if ( ABS_DIFF (current_t, seek_t) > mp->frameDuration() ) {
+
+        // request seek (ASYNC)
+        mp->seekTo(seek_t);
+    }
+
+    // play/stop command should be following the playing mode (buttons)
+    // AND force to stop when the slider is pressed
+    bool media_play = media_playing_mode & (!slider_pressed);
+
+    // apply play action to media only if status should change
+    // NB: The seek command performed an ASYNC state change, but
+    // gst_element_get_state called in isPlaying() will wait for the state change to complete.
+    if ( mp->isPlaying(true) != media_play ) {
+        mp->play( media_play );
+    }
+
+    ImGui::End();
+}
+
 void UserInterface::OpenTextEditor(std::string text)
 {
     currentTextEdit = text;
diff --git a/UserInterfaceManager.h b/UserInterfaceManager.h
index 481ab0b..4f2bfb5 100644
--- a/UserInterfaceManager.h
+++ b/UserInterfaceManager.h
@@ -31,8 +31,7 @@ public:
 
 class UserInterface
 {
-    // own implementation of ImGui 
-    unsigned int textureicons;
+    friend class MainWindow;
     MainWindow mainwindow;
     std::string currentFileDialog;
     std::string currentTextEdit;
@@ -73,6 +72,12 @@ public:
     //
     void OpenTextEditor(std::string text);
 
+protected:
+    bool show_preview;
+    void RenderPreview();
+    bool show_media_player;
+    void RenderMediaPlayer();
+
 };
 
 #endif /* #define __UI_MANAGER_H_ */
diff --git a/View.cpp b/View.cpp
index cc7e766..18ec17e 100644
--- a/View.cpp
+++ b/View.cpp
@@ -31,7 +31,7 @@ void View::update(float dt)
 MixingView::MixingView() : View()
 {
     // default settings
-    scene.root()->scale_ = glm::vec3(1.4, 1.4, 1.0);
+    scene.root()->scale_ = glm::vec3(1.6, 1.6, 1.0);
 
     // Mixing scene
     Mesh *disk = new Mesh("mesh/disk.ply");
diff --git a/defines.h b/defines.h
index 8ed99c1..2023ada 100644
--- a/defines.h
+++ b/defines.h
@@ -22,8 +22,9 @@
 #define CIRCLE_SQUARE_DIST(x,y) ( (x*x + y*y) / (SCENE_UNIT * SCENE_UNIT * SCENE_UNIT * SCENE_UNIT) )
 
 #define IMGUI_TITLE_MAINWINDOW ICON_FA_CIRCLE_NOTCH " v-mix"
-#define IMGUI_TITLE_MEDIAPLAYER ICON_FA_FILM " Media Player"
-#define IMGUI_TITLE_SHADEREDITOR ICON_FA_CODE " Shader Editor"
+#define IMGUI_TITLE_MEDIAPLAYER ICON_FA_FILM "  Media Player"
+#define IMGUI_TITLE_SHADEREDITOR ICON_FA_CODE "  Shader Editor"
+#define IMGUI_TITLE_PREVIEW ICON_FA_LAPTOP "  Preview"
 
 #define COLOR_BGROUND 0.2, 0.2, 0.2
 
diff --git a/main.cpp b/main.cpp
index f741f35..9ced7d3 100644
--- a/main.cpp
+++ b/main.cpp
@@ -44,119 +44,18 @@
 #define PI 3.14159265358979323846
 
 
-void drawMediaPlayer()
+void drawCustomGui()
 {
-    static bool opened = true;
-    static GstClockTime begin = GST_CLOCK_TIME_NONE;
-    static GstClockTime end = GST_CLOCK_TIME_NONE;
-
-    bool show = false;
-    MediaPlayer *mp = nullptr;
-    if ( Mixer::manager().currentSource()) {
-        MediaSource *s = static_cast<MediaSource *>(Mixer::manager().currentSource());
-        if (s) {
-            mp = s->mediaplayer();
-            if (mp && mp->isOpen())
-                show = true;
-        }
-    }
 
     ImGui::SetNextWindowPos(ImVec2(200, 200), ImGuiCond_FirstUseEver);
     ImGui::SetNextWindowSize(ImVec2(300, 300), ImGuiCond_FirstUseEver);
 
-    if ( !ImGui::Begin(IMGUI_TITLE_MEDIAPLAYER, &opened) || !show)
+    if ( !ImGui::Begin("Custom"))
     {
         ImGui::End();
         return;
     }
 
-    float width = ImGui::GetContentRegionAvail().x;
-    float spacing = ImGui::GetStyle().ItemInnerSpacing.x;
-
-    ImVec2 imagesize ( width, width / mp->aspectRatio());
-    ImGui::Image((void*)(intptr_t)mp->texture(), imagesize);
-
-    if (ImGui::Button(ICON_FA_FAST_BACKWARD))
-        mp->rewind();
-    ImGui::SameLine(0, spacing);
-
-    // remember playing mode of the GUI
-    bool media_playing_mode = mp->isPlaying();
-
-    // display buttons Play/Stop depending on current playing mode
-    if (media_playing_mode) {
-
-        if (ImGui::Button(ICON_FA_STOP " Stop"))
-            media_playing_mode = false;
-        ImGui::SameLine(0, spacing);
-
-        ImGui::PushButtonRepeat(true);
-         if (ImGui::Button(ICON_FA_FORWARD))
-            mp->fastForward ();
-        ImGui::PopButtonRepeat();
-    }
-    else {
-
-        if (ImGui::Button(ICON_FA_PLAY "  Play"))
-            media_playing_mode = true;
-        ImGui::SameLine(0, spacing);
-
-        ImGui::PushButtonRepeat(true);
-        if (ImGui::Button(ICON_FA_STEP_FORWARD))
-            mp->seekNextFrame();
-        ImGui::PopButtonRepeat();
-    }
-
-    ImGui::SameLine(0, spacing * 4.f);
-//    ImGui::Dummy(ImVec2(width - 700.0, 0));  // right align
-
-    static int current_loop = 0;
-    static std::vector< std::pair<int, int> > iconsloop = { {0,15}, {1,15}, {19,14} };
-    current_loop = (int) mp->loop();
-    if ( ImGuiToolkit::ButtonIconMultistate(iconsloop, &current_loop) )
-        mp->setLoop( (MediaPlayer::LoopMode) current_loop );
-
-    float speed = static_cast<float>(mp->playSpeed());
-    ImGui::SameLine(0, spacing);
-    ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x - 40.0);
-    // ImGui::SetNextItemWidth(width - 90.0);
-    if (ImGui::DragFloat( "##Speed", &speed, 0.01f, -10.f, 10.f, "Speed x %.1f", 2.f))
-        mp->setPlaySpeed( static_cast<double>(speed) );
-    ImGui::SameLine(0, spacing);
-    if (ImGuiToolkit::ButtonIcon(12, 14)) {
-        speed = 1.f;
-        mp->setPlaySpeed( static_cast<double>(speed) );
-        mp->setLoop( MediaPlayer::LOOP_REWIND );
-    }
-
-    guint64 current_t = mp->position();
-    guint64 seek_t = current_t;
-
-    bool slider_pressed = ImGuiToolkit::TimelineSlider( "simpletimeline", &seek_t,
-                                                        mp->duration(), mp->frameDuration());
-
-    // if the seek target time is different from the current position time
-    // (i.e. the difference is less than one frame)
-    if ( ABS_DIFF (current_t, seek_t) > mp->frameDuration() ) {
-
-        // request seek (ASYNC)
-        mp->seekTo(seek_t);
-    }
-
-    // play/stop command should be following the playing mode (buttons)
-    // AND force to stop when the slider is pressed
-    bool media_play = media_playing_mode & (!slider_pressed);
-
-    // apply play action to media only if status should change
-    // NB: The seek command performed an ASYNC state change, but
-    // gst_element_get_state called in isPlaying() will wait for the state change to complete.
-    if ( mp->isPlaying() != media_play ) {
-        mp->play( media_play );
-    }
-
-    // display info
-//    ImGui::Text("%s %d x %d", mp->codec().c_str(), mp->width(), mp->height());
-//    ImGui::Text("Framerate %.2f / %.2f", mp->updateFrameRate() , mp->frameRate() );
 
     ImGui::End();
 }
@@ -176,31 +75,27 @@ void drawScene()
 
     Source *s = Mixer::manager().currentSource();
     if ( s != nullptr) {
-        s->shader()->accept(v);
+
+        static char buf5[128];
+        sprintf ( buf5, "%s", s->name().c_str() );
+        ImGui::SetNextItemWidth(-100);
+        if (ImGui::InputText("Name", buf5, 64, ImGuiInputTextFlags_CharsNoBlank)){
+            s->rename(buf5);
+        }
+
+        s->mixingShader()->accept(v);
+
+        float width = ImGui::GetContentRegionAvail().x - 100;
+        ImVec2 imagesize ( width, width / s->frame()->aspectRatio());
+        ImGui::Image((void*)(uintptr_t) s->frame()->texture(), imagesize);
+
+        s->processingShader()->accept(v);
     }
 
     ImGui::End();
 }
 
 
-void drawPreview()
-{
-    FrameBuffer *output = Mixer::manager().frame();
-    if (output)
-    {
-        ImGui::SetNextWindowPos(ImVec2(100, 300), ImGuiCond_FirstUseEver);
-        ImGui::SetNextWindowSize(ImVec2(640, 480), ImGuiCond_FirstUseEver);
-        ImGui::Begin(ICON_FA_LAPTOP " Preview");
-        float width = ImGui::GetContentRegionAvail().x;
-
-        ImVec2 imagesize ( width, width / output->aspectRatio());
-        ImGui::Image((void*)(intptr_t)output->texture(), imagesize, ImVec2(0.f, 0.f), ImVec2(1.f, -1.f));
-
-        ImGui::End();
-    }
-
-}
-
 
 int main(int, char**)
 {
@@ -250,11 +145,9 @@ int main(int, char**)
 //    A.addChild(&P);
 //    Mixer::manager().currentView()->scene.root()->addChild(&A);
 
-    // preview window
-    Rendering::manager().PushBackDrawCallback(drawPreview);
+    // custom test window
+//    Rendering::manager().PushBackDrawCallback(drawCustomGui);
 
-    // add media player
-    Rendering::manager().PushBackDrawCallback(drawMediaPlayer);
 
     ///
     /// Main LOOP
diff --git a/rsc/shaders/image.fs b/rsc/shaders/image.fs
index 6426dd3..947ac15 100644
--- a/rsc/shaders/image.fs
+++ b/rsc/shaders/image.fs
@@ -6,22 +6,23 @@ in vec4 vertexColor;
 in vec2 vertexUV;
 
 uniform sampler2D iChannel0;             // input channel (texture id).
+uniform sampler2D iChannel1;             // input mask
 uniform vec3      iResolution;           // viewport resolution (in pixels)
 
 uniform vec4 color;
-uniform float contrast;
-uniform float brightness;
 uniform float stipple;
 
 void main()
 {
     // color is a mix of texture (manipulated with brightness & contrast), vertex and uniform colors
     vec4 textureColor = texture(iChannel0, vertexUV);
-    vec3 RGB = mix(vec3(0.62), textureColor.rgb, contrast + 1.0) + brightness;
-    RGB *= vertexColor.rgb * color.rgb;
+    vec3 RGB = textureColor.rgb * vertexColor.rgb * color.rgb;
 
     // alpha is a mix of texture alpha, vertex alpha, and uniform alpha affected by stippling
-    float A = textureColor.a * vertexColor.a * color.a;
+    vec4 maskColor = texture(iChannel1, vertexUV);
+    float maskIntensity = (maskColor.r + maskColor.g + maskColor.b) / 3.0;
+
+    float A = textureColor.a * vertexColor.a * color.a * maskIntensity;
     A *= int(gl_FragCoord.x + gl_FragCoord.y) % 2 > (1 - int(stipple)) ? 0.0 : 1.0;
 
     // output RGBA
diff --git a/rsc/shaders/image.vs b/rsc/shaders/image.vs
index 38edf2e..0adcc07 100644
--- a/rsc/shaders/image.vs
+++ b/rsc/shaders/image.vs
@@ -19,3 +19,4 @@ void main()
     vertexColor = color;
     vertexUV = texCoord;
 }
+
diff --git a/rsc/shaders/imageprocessing.fs b/rsc/shaders/imageprocessing.fs
index 0541d49..a80b549 100644
--- a/rsc/shaders/imageprocessing.fs
+++ b/rsc/shaders/imageprocessing.fs
@@ -31,7 +31,7 @@ uniform vec4 color;
 // image processing specific
 uniform sampler2D iChannel0;  // input channel (texture id).
 uniform sampler2D iChannel1;
-uniform vec3      iChannelResolution[2]; // input channel resolution (in pixels)
+//uniform vec3      iChannelResolution[2]; // input channel resolution (in pixels)
 uniform vec3      iResolution;           // viewport resolution (in pixels)
 
 uniform float contrast;
@@ -183,8 +183,7 @@ vec3 convolution(mat3 kernel, vec2 filter_step)
 
 vec3 apply_filter() {
 
-    vec2 filter_step = vec2( 1.f / iChannelResolution[0].x, 1.f / iChannelResolution[0].y);
-//    vec2 filter_step = vec2( 1.f / 1280.0, 1.f / 720.0);
+    vec2 filter_step = 1.f / textureSize(iChannel0, 0);
 
     if (filter < 1 || filter > 10)
         return texture(iChannel0, vertexUV).rgb;