Effects that begin with the characters F\_ are effects that are part of the FFmpeg software
as opposed to those coded within the \CGG{} program. These are discussed separately in
\nameref{sec:ffmpeg_audio_video_plugins}.
-Effect plugins modify the track when played, according to how they are set, with no permanent storage of the output except when the project is rendered. There are many Plugins in \CGG{} Infinity which are actually quite easy to use just by experimenting with them. The plugins are shown and selected from the \textit{Resources window} (figure~\ref{fig:video-plugins}). They are described in more detail later.
+Effect plugins modify the track when played, according to how they are set, with no permanent storage of the output except when the project is rendered. There are many Plugins in \CGG{} Infinity which are actually quite easy to use just by experimenting with them.
+The plugins are shown and selected from the \textit{Resources window} (figure~\ref{fig:video-plugins}). They are described in more detail later.
\begin{figure}[htpb]
\centering
In \texttt{Settings$\rightarrow$ Preferences$\rightarrow$ Appearance} tab, there is a pulldown for \textit{Plugin icons} where the user can choose between the \textit{original} icons, \textit{regular} or \textit{smoother}, \textit{cinfinity}\protect\footnote{Cinfinity /2 icon set is credited to Sam - Creative Common By -- \url{https://creativhecommons.org/licenses/by/3.0/}} -- the default modernized set, or \textit{cinfinity2} (figure~\ref{fig:audio-plugins}).
-Note that when you change the plugin icons, your session will automatically save the backup, stop, restart, and reload (figure~\ref{fig:plugin-icons}).
-
\begin{figure}[htpb]
\centering
\includegraphics[width=0.6\linewidth]{audio-plugins.png}
\label{fig:audio-plugins}
\end{figure}
+Note that when you change the plugin icons, your session will automatically save the backup, stop, restart, and reload (figure~\ref{fig:plugin-icons}).
+
\begin{figure}[htpb]
\centering
\begin{tikzpicture}[scale=1, transform shape]
\textit{Realtime} effect plugins are listed in the Resources window as \textit{Audio} Effects and \textit{Video} Effects. Effect plugins are used by dragging them from the Resources window onto an audio track if it is an audio effect or video track if it is a video effect. You will see a colored bar \index{plugins!toolbar} appear beneath the track with the plugin name on it. If there is data on the destination track, the effect is applied to the entire track, unless a edit or a region of the track is selected (wipe selection or In/Out points) in which case the effect is pasted into that region only. If there is no data on the track or no selected region set, the effect is not added.
-Plugins are layered under the track they apply to. When dragging more than one effect onto an armed track, you will see the effects layering from \textit{top to bottom}, on the bottom of that track. When the track is played back, effects are processed from \textit{top to bottom}. The output of the top effect becomes the input of the bottom effect and so on. "The pipeline in Cinelerra's\protect\footnote{credit to Original Creator} plugin design is the \textit{pull} method. The rendering pipeline starts at the final output and the final steps in the rendering pipeline are reading the data from disk. Every step in the rendering chain involves requesting data from the previous step. When the rendering pipeline eventually requests data from a plugin chain, each plugin requests data from the plugin before it. This is less intuitive than the push method but is much more powerful. Realtime plugins written using the pull method can change the rate data is presented to the viewer and the direction of playback. The pull method allows plugins to take in data at a higher rate than they send it out." Side note: if you want to avoid the automatic \textit{top to bottom} application of plugins, you can take advantage of \textit{nested assets} to manipulate the order the plugins are applied (see \ref{sec:nesting_clips_and_assets}).
+Plugins are layered under the track they apply to in what is referred to as the effect bar. Do a double click on the effect bar to select the effect region. When dragging more than one effect onto an armed track, you will see the effects layering from \textit{top to bottom}, on the bottom of that track. When the track is played back, effects are processed from \textit{top to bottom}. The output of the top effect becomes the input of the bottom effect and so on. "The pipeline in Cinelerra's\protect\footnote{credit to Original Creator} plugin design is the \textit{pull} method. The rendering pipeline starts at the final output and the final steps in the rendering pipeline are reading the data from disk. Every step in the rendering chain involves requesting data from the previous step. When the rendering pipeline eventually requests data from a plugin chain, each plugin requests data from the plugin before it. This is less intuitive than the push method but is much more powerful. Realtime plugins written using the pull method can change the rate data is presented to the viewer and the direction of playback. The pull method allows plugins to take in data at a higher rate than they send it out." Side note: if you want to avoid the automatic \textit{top to bottom} application of plugins, you can take advantage of \textit{nested assets} to manipulate the order the plugins are applied (see \ref{sec:nesting_clips_and_assets}).
Instead of dragging from the Resources window, effects may be applied to a single armed track or a region via a popup menu. On the entire track or on a region determined by a selection wipe or by the In/Out points, right click and select \textit{Attach effect} \index{plugins!attch effect} from the popup. The attach effect dialog gives you more capability than just dragging and dropping. For example, the attach effect dialog lets you attach two more types of effects: \textit{shared effects} and \textit{shared tracks} which are explained in a later section. Select a plugin from the Plugins column and hit the green colored checkmark under the plugins column to attach it. The result is the same as if the effect was dragged from the Resources window.
One more method to apply an effect on all armed tracks of the same type (video or audio) is to use the \textit{Video} or \textit{Audio} pulldown \textit{Attach Effect} option. This brings up a menu which has a useful checkbox to \textit{Attach single standalone and share others} (see \ref{sec:shared_effect_tracks}). The default setting is checked on.
+
After attaching an effect to a track, it often needs to be configured. There are two ways to get to the configuration controls. Click on the magnifying glass \index{plugins!show controls} symbol on the right side of the effect bar -- this is the middle symbol on the bar as you can see in the picture below. Alternatively, you can right click on the effect bar to bring up the effect popup which has a \textit{Show} option. Either method causes the GUI for the effect to appear in a separate window. There will not be a popup if the plugin has no GUI.
\CGG{}’s default setup is in the file \texttt{\$CIN\_DAT/expan\-ders.txt} but if the user wants their own specific setup and if the file in \texttt{\$HOME/.\\bcast5/expanders.txt} exists, it will take precedence.
If there are recommendations for other relevant categories, they can be added. The subtree structure is applicable to any of the \textit{Video Effects/Transitions} or \textit{Audio Effects/Transitions}. You can not sort once an expansion is in effect (figure~\ref{fig:expander}).
-The \texttt{expanders.txt} file has very specific requirements. The most specific is that there are no blanks -- you must use tabs only. A \# (pound sign) can be used in column 1 to indicate a comment. A short example of what the txt file looks like is shown below.
-
\begin{figure}[htpb]
\centering
\includegraphics[width=0.8\linewidth]{expander.png}
\label{fig:expander}
\end{figure}
+The \texttt{expanders.txt} file has very specific requirements. The most specific is that there are no blanks -- you must use tabs only. A \# (pound sign) can be used in column 1 to indicate a comment. A short example of what the txt file looks like is shown below.
+
\begin{lstlisting}[style=sh]
Video Effects
-Favorites
\label{sub:live_audio}
\index{live audio}
-The Live Audio effect reads audio directly from the sound card input. It replaces any audio on the track so it is normally applied to an empty track. To use Live Audio, highlight a horizontal region of an audio track or define In and Out points. Then drop the Live Audio effect into it. Create extra tracks and attach shared copies of the first Live Audio effect to the other tracks to have extra channels recorded. Live Audio uses the sound driver selected in \texttt{Settings $\rightarrow$ Preferences $\rightarrow$ Playback A $\rightarrow$ Audio Out for recording}, but unlike recording it uses the playback buffer size as the recording buffer size and it uses the project sample rate as the sampling rate. These settings are critical since some sound drivers can not record in the same sized buffer they play back in.
+The Live Audio effect reads audio directly from the sound card input in real time. It replaces any audio on the track so it is normally applied to an empty track. To use Live Audio, highlight a horizontal region of an audio track or define In and Out points. Then drop the Live Audio effect into it. Create extra tracks and attach shared copies of the first Live Audio effect to the other tracks to have extra channels recorded. Live Audio uses the sound driver selected in \texttt{Settings $\rightarrow$ Preferences $\rightarrow$ Playback A $\rightarrow$ Audio Out for recording}, but unlike recording it uses the playback buffer size as the recording buffer size and it uses the project sample rate as the sampling rate. These settings are critical since some sound drivers can not record in the same sized buffer they play back in.
Live audio has been most reliable when ALSA is the recording driver and the playback fragment size is $2048$. Drop other effects after Live Audio to process sound card input in realtime. With live audio there is no read-ahead, so effects like compressor will either delay if they have read-ahead enabled or playback will under-run. A potential problem is that sometimes the recording clock on the sound card is slightly slower than the playback clock. The recording eventually falls behind and playback sounds choppy. Live Audio does not work in reverse.
LV2\protect\footnote{Optional Feature - OS dependent} is an open standard for audio plugins using a simple interface with extensions which add functionality to support audio software. These plugins were written by external developers and provide additional audio effects to \CGG{} audio without having to change \CGG{} every time. Because the LV2 plugins are separate from \CGG{} Infinity, if one fails or does not perform as expected, \CGG{} should stay running and you will have to contact the programmers responsible for that plugin for a fix.
-Typically, a user OS has specialized package groups installed. It is difficult to create one build of \CGG{} to accommodate all potential LV2 plugins. Specifically for the \textit{Calf-Studio LV2 plugins}, you should install the \textit{Calf Plugins} package. The user’s computer must have \textit{gtk-2-runtime} installed, which seems to be automatically done already for most distros. For users doing their own builds, you can build \CGG{} without LV2 support by including \texttt{-{}-without-lv2} in the configure step. The default build is \texttt{-{}-with-lv2=yes} and requires that \textit{GTK-2-devel} must be installed or the build will fail and notify you. In addition for some newer distros, you will need to install
+Typically, a user OS has specialized package groups installed. It is difficult to create one build of \CGG{} to accommodate all potential LV2 plugins. Specifically for the \textit{Calf-Studio LV2 plugins}, you should install the \textit{Calf Plugins} package. Note that because the Calf Plugins have a graphics UI interface which is dependent on specific hardware, they will not work with AppImage. The user’s computer must have \textit{gtk-2-runtime} installed, which seems to be automatically done already for most distros. For users doing their own builds, you can build \CGG{} without LV2 support by including \texttt{-{}-without-lv2} in the configure step. The default build is \texttt{-{}-with-lv2=yes} and requires that \textit{GTK-2-devel} must be installed or the build will fail and notify you. In addition for some newer distros, you will need to install
\textit{lv2-calf-plugins-gui}; for example Fedora version 32.
LV2 plugins have their own category in the \textit{Audio Plugins Visibility} as lv2. There is a simple text interface which is available via the usual \textit{Show controls} button when the plugin is attached to the audio track. This window has a Reset button to get back to the default settings. To change a value of one of the parameters, highlight that parameter and type in the new value in the topmost text box and then hit Apply to take effect -- the reason for requiring hitting apply is so that the audio is not moving all over the place while you are still typing a value. More easily, you can just move the \textit{pot dial} or the \textit{slider} bar which take effect automatically.
\label{sub:blue_banana}
\index{blue banana}
-Blue Banana\protect\footnote{credit to Monty Montgomery programmer} is an \textit{HSL Qualifier} \index{HSL Qualifier} (HSL= hue, saturation, lightness), one of the basic tools of any grading software that are based on circumscribing a zone of the frame by extracting a chromatic key and producing a \textit{matte} in the alpha channel (Secondary Color Correction). Blue Banana differs not by creating a real matte, but by creating a \textit{selection mask} exclusively for use within the plugin. The BlueBanana plugin has a couple of useful purposes. It can be used for color transformation or remapping -- by isolating a specific color and then performing color change/correction on only that color (or color ranges). Another useful purpose is for chroma-key filtering, using multiple BlueBanana plugins on the same track. Also, it can be used in conjunction with the mask operation of the Compositor. Usage of BlueBanana may seem complicated at first, but it is necessarily so in order to get enough control to produce the desired effect simply and quickly. Just changing a single color is actually quite easy. BlueBanana is keyframable (figure~\ref{fig:bluebanana}).
+Blue Banana\protect\footnote{credit to Monty Montgomery programmer} is an \textit{HSL Qualifier} \index{HSL Qualifier} (HSL= Hue, Saturation, Luminance; HSV in our plugin, with V = Value), one of the basic tools of any grading software that are based on circumscribing a zone of the frame by extracting a chromatic key and producing a \textit{matte} in the alpha channel (Secondary Color Correction). Blue Banana differs not by creating a real matte, but by creating a \textit{selection mask} exclusively for use within the plugin. The three H, S and V sliders are called \textit{qualifiers}. The BlueBanana plugin has a couple of useful purposes. It can be used for color transformation or remapping -- by isolating a specific color and then performing color change/correction on only that color (or color ranges). Another useful purpose is for chroma-key filtering, using multiple BlueBanana plugins on the same track. Also, it can be used in conjunction with the mask operation of the Compositor. Usage of BlueBanana may seem complicated at first, but it is necessarily so in order to get enough control to produce the desired effect simply and quickly. Just changing a single color is actually quite easy. BlueBanana is keyframable (figure~\ref{fig:bluebanana}).
The basic strategy for BlueBanana is to:
\begin{itemize}
- \item Select a specific target color.
+ \item Select a specific target color with the eyedropper tool.
\item Create a selection region by expanding color ranges around that color.
\item Optionally reduce or expand the alpha plane as a regional selection mask.
\item Optionally apply a color remapping or transformation to the selection.
\begin{enumerate}
\item There are color strips under color Adjustment which will show color changes as you modify values.
\item Uncheck Mark Selected Areas and check the Filter Active box to the right of Color Adjustment.
- \item As needed, you can individually check and uncheck all the various parameters using the boxes to the left of each line. Again, these are intuitive and broadly similar to the above. The arrows at the bottom widen the range, the circle at the bottom moves the range, and the top slider, which is an arrow this time, affects distribution. It provides a little histogram effect to give you an idea of what you're changing. The fade adjusts the level of color blending. The alpha is basically the opacity of your changes.
+ \item As needed, you can individually check and uncheck all the various parameters using the boxes to the left of each line. Again, these are intuitive and broadly similar to the above. The arrows at the bottom widen the range, the circle at the bottom moves the range, and the top slider, which is an arrow this time, affects distribution. It provides a little histogram effect to give you an idea of what you are changing. The fade adjusts the level of color blending. The alpha is basically the opacity of your changes.
\end{enumerate}
\end{description}
Definition of Wording/Checkboxes/Buttons/Operators are being described next. Some of the commentary was adopted from information provided by \textit{Monty Montgomery} and from questions and answers from email by \textit{Igor Ubuntu}, who did extensive testing.
-\subsubsection*{Operational characteristics for the \textbf{color-related adjusters}:}
+\subsubsection*{Operational characteristics for the color-related adjusters:}
\label{ssub:operational_characteristic_color}
\begin{description}
- \item[left arrow slider] operates the range minimum; the numerical value shows in the left-most textbox.
- \item[right arrow slider] operates the range maximum; resulting numerical value is in the middle textbox.
+ \item[left arrow slider] operates the range minimum (left edge); the numerical value shows in the left-most textbox.
+ \item[right arrow slider] operates the range maximum (right edge); resulting numerical value is in the middle textbox.
\item[middle circle slider below] can move the current range up or down and the numerical results will show in the left and middle textbox. Move the dot and you move the range.
- \item[top pad slider] operates the edge slopes (selection attack/decay) and the value will be displayed in the
- rightmost textbox. Sharp edges are represented by 0; 100 represents smooth edges.
- \item[top arrow] affects the distribution skew.
+ \item[top pad slider] operates the edge slopes (selection attack/decay) and the value will be displayed in the rightmost textbox. Sharp edges are represented by 0; 100 represents smooth edges. It is only for "Mask Selection" (Pane 1). It applies simultaneously to the left and right edges (symmetric).
+ \item[top arrow] affects the distribution skew. It is the equivalent of Top Pad Slider for Pane 2 ("Color Adjusting").
\end{description}
-\subsubsection*{Operational characteristics for \textbf{Fill}:}
+\textit{Left/Right Arrow} determine the edges of the color range. They are precise edges independent of each other, so we can get asymmetrical ranges with respect to the center of the interval indicated by \textit{middle circle slider below}.
+
+\subsubsection*{Operational characteristics for Fill:}
\label{ssub:operational_characteristic_fill}
\begin{description}
RGBA = red/green/blue color planes, alpha data plane.
YUVA = luma/Cb/Cr color values, alpha data plane.
-The alpha data normally is input to the blending operations in the patchbay overlay mode. The alpha data usually creates the appearance of stacking order, and determines which color planes are visible in the rendered result. When BlueBanana is used, the meaning of the alpha data is changed to the selection. It is useful to think of the alpha data as more solid when it is transparency in blending, and more selected when it is used in BlueBanana. In both cases, the greater the alpha value, the more the effect is expressed.
+The alpha data normally is input to the blending operations in the patchbay overlay mode. The alpha data usually creates the appearance of stacking order, and determines which color planes are visible in the rendered result. When BlueBanana is used, the meaning of the alpha data is changed to the selection. It is useful to think of the alpha data as more solid then it is transparency in blending, and more selected when it is used in BlueBanana. In both cases, the greater the alpha value, the more the effect is expressed.
-Usually, alpha is normalized to a range from $0$ to $1$, zero = no effect, $1$ = total effect, $0.5$ = partial effect. In both cases, alpha is what math people call an auxiliary variable. It is needed, but is not part of the answer. In this case, the answer is the visible rendered result. Alpha is like meta-data.
+Usually, alpha is normalized to a range from $0$ to $1$, zero = no effect, $1$ = total effect, $0.5$ = partial effect. In both cases, alpha is what math people call an auxiliary variable. It is needed, but is not part of the answer. In this case, the answer is the visible rendered result. Alpha is like meta-data. Note that the "alpha" slider works with both "Filter Active" and "Mask Selection" checkboxes
+checked. The "Filter Active" checkbox enables the options: red, green, blue, hue, saturation, value, fade, alpha. If "Mask Selection" is not checked "alpha" will not work.
Let us now examine the instruments in \textbf{pane 1}:
\item[Hue] select a hue domain; click on the Pick button to select or check the box to the left of hue or uncheck to ignore.
\item[Saturation] select a saturation domain; click on the Pick button to select or check the box to the left.
\item[Value] select a value domain; click on the Pick button to select or check the box to the left.
- \item[Fill] will fill more area or less area of your selected region. This describes how it works. Fill control is an automated way of doing grow and shrink on the selected area, to fill in small holes, or get rid of scattered speckles. If none of the Hue, Saturation, or Value sliders are active -- meaning that the whole frame is selected -- the Fill slider will have no effect even when enabled. The word fill will appear ghosted to indicate this.
+ \item[Fill] will fill more area or less area of your selected region. This describes how it works. Fill control is an automated way of doing grow and shrink on the selected area, to fill in small holes in the middle of the selection, or to eliminate spurious pixels that are on the outer or inner edge of the selection. Be careful how much you shrink, because it can lead to edge segmentation with visible and annoying blocks of pixels. This is where Blur plugin can help. Blur should not be overdone so as not to create unsightly halos.
+
+ If none of the Hue, Saturation, or Value sliders are active -- meaning that the whole frame is selected -- the Fill slider will have no effect even when enabled. The word Fill will appear ghosted to indicate this.
The three lower handles in the fill slider correspond to \textit{Shrink} (the left hand slider), \textit{Final} (the middle slider), and \textit{Grow} (the right hand slider). These are used in combination to alter the selection by first growing it by the amount specified by the right hand Grow slider, shrinking it to the amount specified by the left hand Shrink slider, and then growing it again to the final size specified by the middle Final slider. The top slider then feathers the resulting selection.
- Growing the selection and then shrinking it has the effect of filling small holes in the selected area. Similarly, shrinking and then growing tends to remove small flecks of unwanted selection. The Final slider specifies the overall desired shrinkage or growth of the selection when finished. To specify a pure Grow or Shrink operation, set the Final slider and the Grow/Shrink slider to the same value and leave the other slider at zero.
+ Growing the selection it has the effect of filling small holes in the selected area. Similarly, shrinking and then growing tends to remove small flecks of unwanted selection. The Final slider specifies the overall desired shrinkage or growth of the selection when finished. To specify a pure Grow or Shrink operation, set the Final slider and the Grow/Shrink slider to the same value and leave the other slider at zero.
\item[Pre-erode] this control reverses the order of operation to Shrink, then Grow, then Final. The change is subtle on most images, but overall removes more small features because it first removes flecks before filling in holes.
\end{description}
\item[Alpha] controls the output alpha (this is not available when End Mask is set); click the Reset button to revert to default. Result is reflected in the numerical textboxes on the right-hand side.
\end{description}
-Let's see two examples of HowTo:
+\subsubsection*{Tips}
+\begin{enumerate}
+ \item In Pane 1, for mask selection creation, you can also use only one or two (checked or Pick button) of the three qualifiers Hue/Saturation/Value. With Hue alone you get a precise range of hues. With Saturation you select those saturation values for all hues, and with Value you do a "Luma Key," that is, you isolate only certain gray values. It may be useful to start with only one qualifier, and then gradually activate the others; but there are important cases that require all three bars. For example, skin tones, which are always characterized by a mixture of shadows, highlights, and different levels of saturation.
+ \item Hue and Saturation Qualifiers can be inaccurate if the file is highly compressed and with Subsampling type $4:2:0$. There are indeed blocks and macroblocks of pixels, visible especially along the edges, that disturb the creation of the selection mask. Better to use high quality files at least $4:2:2$, better still $4:4:4$. The brightness Y channel, on the other hand, is always at the highest quality (4). The presence of color noise can also be a problem because it creates spurious pixels. A tip may be to work on and enhance the clip before applying Blue Banana.
+ \item If there are unwanted (spurious) selections in the frame that are small and far from the main selection, they can be eliminated or minimized with some Blur. Larger spurious selections can be eliminated by masking them (with the \texttt{Mask selection} option enabled in Blue Banana and with the \texttt{Apply mask before plugins} option in Mask tool). This is an action analogous to \textit{garbage matte} in Chroma Key. If there are many spurious areas, perhaps with complex motions, it is best to mask only the selection we are interested in and then bring the \texttt{Fade} slider to $-100$ to reverse the mask.
+ \item To select multiple colors in the same clip we can use multiple instances of Blue Banana.
+ \item Once a satisfactory selection mask has been created, scroll through the entire clip to see the presence of artifacts, defects, or spurious areas in the other frames.
+ \item It is known that primary Color Correction precedes secondary CC. However, if we use primary CC tools that cause the highlights and deep blacks to clip, for example the histogram, we will get clipped areas that then, in secondary CC, cannot be recovered. We can then first do a secondary CC for the areas near the white point and the black point using Blue Banana which works at 32bit Float. For example, we can turn down the highlights so as to reveal details and the same can be done in the shadows. Once we have worked in these details without causing clipping (that is, reported within the standard range) we can switch to primary CC.
+\end{enumerate}
+
+Let's see two examples of HowTo:
\subsubsection*{BlueBanana Use Case \#1: (Color Transform/Remapping)}
\label{ssub:bb_use_case_1}
\item[Alpha determines radius] use alpha to define the amount of blur to apply. (radius=gray value of alpha)
\item[Blur alpha, red, green, blue] specifies which color channels is to be blurred.
\end{description}
+If you are getting confusing results with old projects it may be a
+result of the discontinued parameter \textit{alpha determines radius}.
+For compatibility reasons and for possible future development it
+has been left in the code but hidden in the plugin's GUI.
+The parameter for \textit{alpha determines radius} is
+\texttt{A\_KEY}, which can be 0 or 1. When you press the
+\texttt{Reset} button in the Blur plugin window \texttt{A\_KEY=0}.
+
+Old projects may have saved that parameter (A\_KEY) to 1 instead
+of 0 and that may present a problem so you should do one of
+the following workarounds to change it to 0. Then be sure to save
+your project with these changes applied.
+\begin{enumerate}
+ \item Click on the \textit{Reset} button in the dialogue/controls popup box and re-enter any of your other parameter desired values.
+ \item OR in the \CGG{} program, open the project. Click on the cog icon
+(\textit{Preset edit}) of the Blur effect bar and the \textit{Keyframe
+parameters} window is open. There, you can see the A\_KEY parameter
+and change it: select the \texttt{A\_KEY} parameter and in the
+\texttt{Edit value} box, change it from 1 to 0, then press the \texttt{OK}
+button.
+\end{enumerate}
\subsection{BoxBlur}%
\label{sub:boxblur}
\label{sub:chroma_key}
\index{chroma key}
-This effect erases pixels which match the selected color. They are replaced with black if there is no alpha channel and transparency if there is an alpha channel. In this case, you create a matte in the alpha channel, which is not visible to us. The selection of color model is important to determine the behavior (figure~\ref{fig:chroma-key}).
+This effect erases pixels which match the selected color. They are replaced with black if there is no alpha channel and transparency if there is an alpha channel. In this case, you create a matte in the alpha channel, which is not visible to us. The selection of color model is important to determine the behavior (figure~\ref{fig:chroma-key}).
\begin{figure}[htpb]
\centering
\label{fig:chroma-key}
\end{figure}
-Chroma key uses either the \textit{lightness} or the \textit{hue} to determine what is erased. Use value singles out only the lightness to determine transparency.
+Chroma key uses either the \textit{lightness} or the \textit{hue} to determine what is erased. Use value singles out only the lightness to determine transparency (Luma Key).
Select a center color to erase using the \textit{Color} button. Alternatively a color can be picked directly from the output frame by first using the \textit{color picker} in the compositor window and then selecting the \textit{Use color picker} button. This sets the chroma key color to the current color picker color.
Be aware that the output of the chroma key is fed back to the compositor, so selecting a color again from the compositor will use the output of the chroma key effect. The chroma key should be disabled when selecting colors with the color picker.
\label{sub:chroma_key_hsv}
\index{chroma key HSV}
-Chroma Key (HSV)\protect\footnote{Credit for Plugin by Jerome Cornet \url{http://jcornet.free.fr/linux/chromakey.html}} (figure~\ref{fig:chroma-key-hsv}) replaces a color with another color or transparency using HSV variables; it is frequently used to remove a color from a video to composite with another image. This process is generally referred to as green screen or blue screen process (because of the color that is keyed out). More information: {\small \url{http://en.wikipedia.org/wiki/Chromakey}}
+Chroma Key (HSV)\protect\footnote{Credit for Plugin by Jerome Cornet \url{http://jcornet.free.fr/linux/chromakey.html}} (figure~\ref{fig:chroma-key-hsv}) replaces a color with another color or transparency using HSV variables; it is frequently used to remove a color from a video to composite with another image. This process is generally referred to as green screen or blue screen process (because of the background color that is keyed out). More information: {\small \url{http://en.wikipedia.org/wiki/Chromakey}}
\begin{figure}[htpb]
- \centering
- \includegraphics[width=0.55\linewidth]{chroma-key-hsv.png}
- \caption{Keying a green screen with Chroma Key (HSV)}
- \label{fig:chroma-key-hsv}
+ \centering
+ \includegraphics[width=0.55\linewidth]{chroma-key-hsv.png}
+ \caption{Windows config for Chroma Key (HSV)}
+ \label{fig:chroma-key-hsv}
\end{figure}
\subsubsection*{Requirements}
\label{ssub:requirements}
-The subject in the movie should have a good background. The lighting is crucial and good lighting during production will save you time with much less effort than in post-production.
-Here we assume that we have a good video, filmed on green (or blue) screen that we want to use. Important: Make sure you are using a color model that has an alpha channel, such as \textit{RGBA8}, \textit{RGBAFloat}, \textit{YUVA8}. To change color model, go to \texttt{Settings $\rightarrow$ Format $\rightarrow$ Color Model}.
+The subject in the movie should have a good background. The lighting is crucial and good lighting during production will save you time with much less effort than in post-production. Another tip is to use a low-compressed, intraframe codec with as high a color depth as possible. In case of YUV-type source signal, it is better to have subsampling $4:4.4$ or $4:2:2$.
+Here we assume that we have a good video, filmed on green (or blue) screen that we want to use. Important: make sure you are using a color model that has an alpha channel, such as \textit{RGBA8}, \textit{RGBAFloat}, \textit{YUVA8}. To change color model, go to \texttt{Settings $\rightarrow$ Format $\rightarrow$ Color Model}.
\subsubsection*{Usage}
\label{ssub:usage}
As in any other effect, add it to the timeline in the main window. You can tweak each parameter in order to improve the keying.
+To understand how the plugin parameters work, we need to refer to the HSV color wheel (foreground color) in figure~\ref{fig:hsv_color_wheel}. Coinsider that this is an abstract example; in the real world we will be dealing with much more complicated masks.
+
+\begin{figure}[htpb]
+ \centering
+ \includegraphics[width=0.9\linewidth]{hsv_color_wheel.png}
+ \caption{Various parameters in the 'Color' and 'Key Parameters' sections.}
+ \label{fig:hsv_color_wheel}
+\end{figure}
+
+The left half has Saturation from 0 (in the center) to 100 on the edges. An example of a green screen is shown here. The right half has brightness from 0 (center) to 100 on the edges. The example of a blue screen is given here. The key color is the radius of the wheel, and its angle determines the hue. The Hue Tolerance is the arc of a circle (a wedge) that includes the radius. The wedge is the color range (mask) that we want to eliminate by keying, its shape is precise and easy to understand. The Brightness are the inner/outer extremes of the wedge; if the inner value (Min) is 0, then it coincides with the center point, if the outer value (max) is 100 then it coincides with the arc on the circumference. With intermediate values we will have masks similar to the one shown in the figure. Min Saturation is the distance from the center, along the Hue radius, from which we want to impose saturation with the value 0. It will be the value from which keying starts. Saturation Offset is an additional cut we make to the inner part of the wedge from the Min Saturation value. All of these adjustments allow us to establish a range of colors (Mask) that perfectly matches the background (the wedge in the example in the figure) that we want to eliminate. This is a precision operation, and it is not rare to return to the parameter combination several times to refine the mask.
+
Start with \textit{Hue Tolerance} at $10\%$, \textit{Min Bright\-ness} at $0$, \textit{Max bright\-ness} at $100\%$, \textit{Saturation offset} at $0$, \textit{Min Saturation} at $0$, \textit{In Slope} at $0$, \textit{Out Slope} at $0$, \textit{Alpha Offset} at $0$ (that’s mid-way through), \textit{Spill Threshold} at $0$, \textit{Spill Compensation} at $100\%$. At any time, you can check what the Mask looks like by clicking on \textit{Show Mask}. This will output a black and white image of the mask (\textit{matte}).
+\qquad \textit{Color section}
+
+In this section of the configuration window, you choose the key color and have the ability to see the mask created.
+
+\begin{description}
+ \item[Color...] Select the key color (green, blue, etc) using the color wheel or the color picker. Remember, only the Hue matters, not Saturation or Value. To use the color picker, click on the \textit{color picker} icon in the Compositor window, then click on the color you want in the Compositor window. Finally in the Chromakey (HSV) parameters window, click on \textit{Use Color Picker}. Remember to disable ChromaKey (HSV) plugin when using the Color Picker on the Compositor window.
+ \item[Show Mask] The plugin does not create a true matte in the alpha channel, but creates a mask. Activating this option will show the foreground as a white (opaque) shape while the background in black (transparency). You will be able to control the extent of the mask, any jagged edges, small black areas within the mask or small white areas within the foreground, which are to be removed, etc.
+\end{description}
+
+\qquad \textit{Key parameters section}
+
+In this section we expand the mask to a range of colors close to color key and refine the selection by also taking advantage of brightness and saturation.
+
\begin{description}
- \item[Key color:] Select the key color (green, blue, etc) using the color wheel or the color picker. Remember, only the Hue matters, not Saturation or Value. To use the color picker, click on the \textit{color picker} icon in the Compositor window, then click on the color you want in the Compositor window. Finally in the Chromakey (HSV) parameters window, click on \textit{Use Color Picker}.
- \item[Hue Tolerance:] Because there are slight variations in lighting, the background will not be in a uniform key color hue. Increase or decrease the Hue tolerance to mask out the background. If there are dark spots that are keyed out that shouldn’t be, it can be corrected later.
- \item[Brightness:] ncrease \textit{Min Brightness} so that only the background is masked out, and not parts of the foreground. You can also reduce \textit{Max Brightness} if some clear areas are keyed out (useful for very dark backgrounds).
- \item[Saturation:] Increase \textit{Min Saturation} so that only the background is masked out, and not parts of the foreground. \textit{Saturation Offset} can be used to change this, but for now leave it set to $0$.
+ \item[Hue Tolerance:] Because there are slight variations in lighting in real cases, the background will not be in a uniform key color hue. Increase or decrease the Hue tolerance to mask out the background. If there are dark spots that are keyed out that shouldn’t be, it can be corrected later (With the \texttt{Mask} tool, this operation is called the \textit{Garbage Matte}).
+ \item[Brightness:] It allows the color range (Mask) to be better defined by exploiting the differences in brightness between background and foreground. This could be referred to as a Luma Key within the Chroma Key. Increase \textit{Min Brightness} so that only the background is masked out, and not parts of the foreground. You can also reduce \textit{Max Brightness} if some clear areas are keyed out (useful for very dark backgrounds).
+ \item[Saturation:] It allows the color range (Mask) to be better defined by exploiting the differences in saturation between background and foreground. Since the best results are obtained by keying pure colors, it may come in handy to eliminate the less saturated colors (proper to the foreground) while leaving the more saturated colors (proper to the background, i.e. Green/Blue Screen) to the keying action. Increase \textit{Min Saturation} so that only the background is masked out, and not parts of the foreground. \textit{Saturation Offset} can be used to change this, because it acts similarly to Min Brightness. It could be said that Min Saturation concerns only the key color, while Saturation Offset concerns the range of Hue tolerance. But it is best to start by leaving it at $0$.
\end{description}
Check what it looks like at this stage, your mask should be pretty
compositing later on. They will help you to make your key look much
cleaner.
+\qquad \textit{Mask tweaking section}
+
+In this section you intervene on the already created mask with edge smoothing and transparencies.
+
+\begin{description}
+ \item[Slope:] For now, the mask is a full on/ full off mask that can be really harsh on the edges and not necessarily what you are looking for. \textit{In Slope} and \textit{Out Slope} will help you to smooth that key. In Slope it acts on the inner side of the edges by grading them with keying (background) colors. It leaves more colors in the mask. Out Slope acts on the outer side of the edges by grading them with the foreground colors. It takes more colors out of the mask. Basically, the colors that are borderline in the mask will see their alpha channel reduced by half instead of being completely on or off.
+ \item[Alpha Offset:] This control offsets the whole alpha channel by some amount (from -100=full opacity to +100=full transparency). Be sure to know what you are doing if you change it from the default value of $0$.
+\end{description}
+
+\qquad \textit{Spill light control section}
+
+In this section we try to make halos, reflections and parasitic lights present on the foreground less noticeable.
+
\begin{description}
- \item[Slope:] For now, the mask is a full on/ full off mask that can be really harsh and not necessarily what you are looking for. \textit{In Slope} and \textit{Out Slope} will help you to smooth that key. In Slope leaves more colors in the mask, Out Slope takes more colors out of the mask. The colors that are borderline in the mask will see their alpha channel reduced by half instead of being completely on or off.
- \item[Alpha Offset] This control offsets the whole alpha channel by some amount. Be sure to know what you are doing if you change it from the default value of $0$.
- \item[spill light control:] This step helps you remove the green or blue halo around the edges of the mask. It does so by removing the saturation of pixels that have a similar hue to the key color (turning them into grey instead of green or blue). \textit{Spill Compensation} controls the amount of de-saturation. If you start with Spill Compensation at $100\%$, slowly increase the \textit{Spill Threshold} until the remaining green or blue areas turn grey. Then reduce Spill Compensation until the image looks good.
+ \item[spill light control:] This step helps you remove the green or blue halo around the edges of the mask. It does so by removing the saturation of pixels of the foreground that have a similar hue to the key color (turning them into grey instead of green or blue). The hues to be desaturated are set with \textit{Spill Threshold}, the degree of desaturation is set with \textit{Spill Compensation}. In order for Spill compensation to work, Spill Threshold must be > 0. If you start with Spill Compensation at $100\%$, slowly increase the \textit{Spill Threshold} until the remaining green or blue areas turn grey. Then reduce Spill Compensation until the image looks good.
\end{description}
Now the mask is probably still very harsh, so just below the Chromakey (HSV) plugin, add a \textit{Blur} effect, and select only the \textit{Alpha channel}, with a radius of $2$ or $3$ (more if you really want to soften the edges). This will significantly help the keying.
\item Create a Stylized look.
\end{itemize}
+When using the X11 graphics driver and RGBA-FLOAT color model, this plugin allows for greater than (0 - 1.0f) values (HDR). This does not work when using X11-OpenGL because it is an 8-bit limited driver. HDR values will only work for the color wheel, while the Value and Saturation sliders are always clipped to 1.0.
+
\subsection{Color Balance}%
\label{sub:color_balance}
\index{color balance}
Mathematically, the gamma function is exponential
($output = input^{\gamma}$) and therefore the inverse of the
-logarithmic function [$output = \log(input)$]. Actually the formula
+logarithmic function [$\gamma = \log_{input}{(output)}$]. Actually the formula
used by the \CGG{} plugin is: $output = input^{\frac{1}{\gamma}}$
which allows for a range of values $0 \div 1.0$. The gamma effect
converts the logarithmic colors to linear colors through a
determines how steep the output curve is (i.e.\ the value of the
gamma parameter; for color space Rec709 is $2.4$
($\frac{1}{\gamma} =0.41\dots$), for sRGB is $2.2$
-($\frac{1}{\gamma} =0.45\dots$), etc.). The maximum value is where
+($\frac{1}{\gamma} =0.45\dots$), etc.). We use $ \dfrac{1}{\gamma}$ because with $\gamma < 1$ there is gamma compression of the curve, increasing the output values relative to the linear (see figure~\ref{fig:gamma02}.). With $\gamma > 1$ we have gamma expansion, typically used to linearize a compressed gamma curve (\textit{Log}). The maximum value is where
$1.0$ in the output corresponds to maximum brightness in the
input. It serves to avoid clipped values because it allows you to
set the maximum value of the output, $1.0$, whenever range
\begin{figure}[htpb]
\centering
- \includegraphics[width=1.0\linewidth]{gamma01.png}
+ \includegraphics[width=0.8\linewidth]{gamma01.png}
\caption{settting \textit{Maximun} to $0.6900$}
\label{fig:gamma01}
\end{figure}
\begin{figure}[htpb]
\centering
- \includegraphics[width=1.0\linewidth]{gamma02.png}
+ \includegraphics[width=0.8\linewidth]{gamma02.png}
\caption{Setting \textit{Maximun} to $0.6100$ and \textit{Gamma} to $0.3300$}
\label{fig:gamma02}
\end{figure}
\label{sub:histogram}
\index{histogram}
-The histogram allows an immediate view of the contrast amplitude of an image with its distribution of \textit{luma} and \textit{colors} values. If the columns of values occupy the whole range $0-1.0\%$ (also expressed as a percentage above the graph) then we have maximum contrast; if the range is smaller the contrast is smaller. In fact, contrast is mathematically given by the highest value of the abscissa minus the lowest value. If the values are similar and close together, the difference is smaller and the lower the contrast. If most of the values are on the right of the histogram you have an image with highlights at the limit with values clamped to $1.0$. This is called \textit{overexposure}. However, if most of the values are moved to the left, with the limit of the values clamped to $0$, we have a lowlight image and we talk about \textit{underexposure}. This plugin is a tool for Primary Color Correction, that is, affecting the entire frame. Histogram is keyframable (figure~\ref{fig:histogram}).
+The histogram allows an immediate view of the contrast amplitude of an image with its distribution of \textit{luma} and \textit{colors} values. If the columns of values occupy the whole range $0-1.0$ (also expressed as a percentage above the graph) then we have maximum contrast; if the range is smaller the contrast is smaller. In fact, contrast is mathematically given by the highest value of the abscissa minus the lowest value. If the values are similar and close together, the difference is smaller and the lower the contrast. If most of the values are on the right of the histogram you have an image with highlights at the limit with values clamped to $1.0$. This is called \textit{overexposure}. However, if most of the values are moved to the left, with the limit of the values clamped to $0$, we have a lowlight image and we talk about \textit{underexposure}. This plugin is a tool for Primary Color Correction, that is, affecting the entire frame. Histogram is keyframable (figure~\ref{fig:histogram}).
\begin{figure}[htpb]
\centering
\label{fig:histogram}
\end{figure}
-The Histogram is always performed in floating point RGB regardless of the project color space. The histogram has two sets of transfer parameters: the \textit{input transfer} and the \textit{output transfer}. The input transfer has value on the horizontal axis of $x$; it is a normalized scale of values ranging from 0 - 1.0 (which for a depth color of 8 bits corresponds to the range 0 - 255, for 10 bits corresponds to 0 - 65536, etc). The output transfer (the $y\,axis$) represents the number of times (that is, $y$) a given value $x$ appears. A higher column ($y$ greater) indicates that many pixels have the corresponding value $x$; a lower column indicates that fewer pixels have that value. On the left we have the minimum value $0$, which is the black point. On the right we have the maximum value $1.0$ which is the white point. The intermediate values pass smoothly from one extreme to the other. The three important points (including the midtones) are indicated by cursors (small triangles) at the base of the histogram. You can adjust them to change the values of the three points if you want. Acting on the white or black point involves horizontal shifts only; acting on the midtones triangle also involves vertical movements leading to a "gamma" correction of the curve (Linear to Log or Reverse Log or vice versa). Further down is an additional bar with related cursors and textboxes. It is used to adjust input and output values (on the vertical).
+The Histogram is always performed in floating point RGB regardless of
+the project color space, but with clipping at 1.0. When using the X11
+graphics driver and RGBA-FLOAT color model, Histogram allows you to
+display greater than (0 - 1.0f) values to accomodate HDR. This does
+not work when using X11-OpenGL because it is an 8-bit limited driver.
+The display will stop at +110\%, but there is no clipping. By lowering
+the brightness all out-of-range values become visible, even those
+initially above 110\%.
+
+The histogram has two sets of transfer parameters: the \textit{input transfer} and the \textit{output transfer}. The input transfer has value on the horizontal axis of $x$; it is a normalized scale of values ranging from 0 - 1.0 (which for a depth color of 8 bits corresponds to the range 0 - 255, for 10 bits corresponds to 0 - 65536, etc). The output transfer (the $y axis$) represents the height of the column where a given value $x$ appears. A higher column ($y$ greater) indicates that many pixels have the corresponding value $x$; a lower column indicates that fewer pixels have that value. On the left we have the minimum value $0$, which is the black point. On the right we have the maximum value $1.0$ which is the white point. The intermediate values pass smoothly from one extreme to the other. The three important points (including the midtones) are indicated by cursors (small triangles) at the base of the histogram. You can adjust them to change the values of the three points if you want. Acting on the white or black point involves horizontal shifts only; acting on the midtones triangle also involves vertical movements leading to a "gamma" correction of the curve (Linear to Log or Reverse Log or vice versa). Further down is an additional bar with related cursors and textboxes. It is used to adjust input and output values (on the vertical).
There are 4 possible histograms in the histogram viewer. The red, green, blue histograms show the input histograms for red, green, blue and multiply them by an input transfer to get the output red, green, blue. Then the output red, green, blue is scaled by an output transfer. The scaled red, green, blue is converted into a value and plotted on the value histogram. The value histogram thus changes depending on the settings for red, green, blue. The value transfers are applied uniformly to R, G, B after their color transfers are applied. Mathematically, it is said that the values of $x$ are linked to the values of $y$ by a transfer function. This function, by default, is represented by a line that leaves the values of $x$ and $y$ unchanged, but we can intervene by modifying this line with the cursors or the textboxes.
After the input transfer, the image is processed by the output transfer. The output transfer is simply a minimum and maximum to scale the input colors to. Input values of $1.0$ are scaled down to the output's maximum. Input values of $0$ are scaled up to the output minimum. Input values below $0$ are always clamped to $0$ and input values above $1.0$ are always clamped to $1.0$. Click and drag on the output gradient's triangles to change it. It also has textboxes to enter values into.
-Enable the \textbf{Automatic} toggle to have the histogram calculate an automatic input transfer for the red, green, and blue but not the value. It does this by scaling the middle $99\%$ of the pixels to take $100\%$ of the histogram width. The number of pixels permitted to pass through is set by the \textit{Threshold} textbox. A threshold of $0.99$ scales the input so $99\%$ of the pixels pass through. Smaller thresholds permit fewer pixels to pass through and make the output look more contrasty.
+Enable the \textbf{Automatic} toggle to have the histogram calculate an automatic input transfer for the red, green, and blue but not the value. It does this by scaling the middle $99\%$ of the pixels to take $100\%$ of the histogram width. The number of pixels permitted to pass through is set by the Threshold \textbf{textbox}. A threshold of $0.99$ scales the input so $99\%$ of the pixels pass through. Smaller thresholds permit fewer pixels to pass through and make the output look more contrasty.
\textit{Plot histogram} is a checkbox that enables plotting the histogram. It can be useful because having a histogram that changes in real-time can use a lot of system resources for computation. In this case it is enabled only at times when it is needed.
\textit{Split output} is a checkbox that enables a diagonal split showing in the compositor, so we can see the effects of the changes from the original frame.
\textit{Reset} returns the four curves to their initial state (neutral) as well as the Value/RGB histogram buttons.
there is a large light or color variation within a range of a few frames,
you spend a lot of time correcting each frame when it would be better to
just get an average value to use. If you want, then you can make a LUT for
-that set of frames instead of each frame.
-
+that set of frames instead of each frame.\\
It works by selecting the area on the timeline for
which you would like to see the Histogram averaged and then click on the
\textbf{sum frames} button in the Histogram plugin. If a Selection is set on the timeline, the number of frames will be calculated and equalized to the mean value.
\paragraph{Theory:}
-A digital image is an matrix of ($N x N$) pixels. Each pixel can have a (integer) luminance or luma ($r$) value ranging from $0$ to $L-1$. Generally we have $L = 2^{m}$ values of r, with m = depth of color bit. $0 = r_{min}$ is the black point. $L-1 = r_{max}$ is the white point. Mathematically we can act on the values of r with various transformation functions. The generic formula is:
-
-\qquad \( s = T(r) \)
-
-with:
-
-s = luma value after transformation
-r = initial luma value
-T = transformation operator
-
-The T function in the case of a histogram is:
+For more on the mathematical aspect see here:
-\qquad \( s = p(r_{k}) \)
+{\small \url{https://thirdspacelearning.com/gcse-maths/statistics/histogram/}}
-$T(r) = p(r_{k}$) is the transformation that expresses the probability of an image pixel to have a given luma value $r_{k}$. This is referred to as the frequency of the value or the number of occurrences of the value. The total probability of all pixels in the image is 1 (100\%):
+For our discussion, it is enough to understand a few concepts. Each vertical line we see in the histogram is not a simple line, but a rectangle having a certain base. This base is given by the values of $x_i$ present at the edges of the rectangle \textit{i} (pixel range, $x_{max_i} - x_{min_i}$). Rectangles are called \textit{Bins} or Accumulators. The bin's number is of fixed and known size because it depends on the color depth. The bin height is our output $y$ and the bin area ($A_i = f(x_i)$) is known because it represents the \textit{number of occurrences} that are read in bin, also called \textit{frequency ($f_x$)}. The plugin scans the entire range of $x_i$, from 0 to 1.0, and records all the occurrences within each bin. The value of $f_x$ for each bin is the \textit{max} value. At this point knowing base and area, we can obtain the value of $y$ axis that is reported in the histogram.
-\qquad \( \sum_{r=0}^{L-1}{p(r_{k})} = 1 \)
+$width = b_i = x_{max_i} - x_{min_i}$
-Trivially, the function $p(r_{k})$ can be thought of as counting the recurrences of the value $r_{k}$.
-The histogram is similar to a bar graph (not the same: the histogram uses continuous data, the bar graph uses discrete data) and on the abscissa it shows $r_{k}$ values and on the ordinate $p(r_{k})$. Each abscissa value is treated as independent of neighboring values so it is considered as an isolated unit called an "accumulator" or "bin." It is on the bins that we count the occurrence of the $r_{k}$ value (occurrences), which gives us precisely the value $p(r_{k})$. It is called a bar graph because a value of r is actually an interval between $r_{k}$ and the next value $(r_{k+\varepsilon})$. Because r has continuous values computed in floating point and normalized interval $0 - 1.0$ is used, there is no solution of continuity between one bin and another and the boundaries are decided a priori, usually based on bit depth color. The bin concept is fundamental because it is the basis on which we can do mathematical calculations. In fact, the height of the bin is the frequency (count) in which that value occurs; the width of the bin is the range of values within the range we consider. With 8 bits of depth color we have 256 bins; then we collect the values of r from the initial value 0 up to and including 1; then from 1 up to and including 2; and so on up to the last bin, which ranges from 254 to and including 255. It is clear, then, that the continuous luma values are bounded in a range and made to become discrete values on which it is easier to perform calculations. The width of a bin is given by the formula:
+Having established the depth color, the bin width is always the same (b) for every $bin_i$:
-$width = \dfrac{range}{\# bins}$
+$b_i = b = \dfrac{range(1.0-0)}{\# bins}$
-For a depth color of 8 bits we have (normalized range $0 - 1.0$):
+$A_i = f(x_i) = max_i = Base \times High = b \times y_i$
-$width = \dfrac{(1.0-0)}{256} = 1/256$
+Hence:
-For a depth color of 10 bits or more we have:
+$y_i = \dfrac{f(x_i)}{b}$
-$width = \dfrac{(1.0-0)}{65536} = 1/65536$
-
-Wider bins have a higher count (because they gather more $r_{k}$). Narrower bins have a lower count (because they contain less $r_{k}$; neighboring values ($r_{k+i}$) are distributed in neighboring bins).
-To recap: in \CGG{} histogram is a bunch of \textit{bins} (accumulators) that count the number of times a particular pixel channel intensity (luma, $r_{k}$) occurs in an image. The plugin scans all the pixels in the frame, counting the occurrences in each given bin. Dim are on the left, bright on the right.
+Dim bins are on the left, bright bins on the right.
You can have discordance of results, looking in the scopes, either by switching from Histogram to Histogram Bezier or after a conversion between color spaces (with associated change in depth color). The number of bins used depends on the color model bit depth:
\begin{description}
\item[Scopes:] the curve is Log
\end{description}
-This diversity also leads to different visual results from Histogram Bezier.
+This diversity also leads to different visual results from Histogram Bezier or Videoscope.
When the color space and the bin size are the same, all of the values increment the indexed bins. But if we start from YUV type edits, the plugin will automatically do the conversion to RGB. When the color is the result of yuv $\rightarrow$ rgb float conversion, we go from 256 bins of YUV to 65536 bins of RGB Float and the results \textit{spread} if there are more bins than colors. This is the same effect you see when you turn on \textit{smoothing} in the vectorscope histogram.
-The \textit{total} pixels for each value is approximately the same, but the \textit{max} value depends on the color quantization. More colors increment more bins. Fewer colors increment fewer bins. In both cases, the image size has the same number of pixels. So the pixels will distribute into more bins if you go to a higher depth color; those bins will have a lower count. The fewer color case increments the used bins, and skips the unused bins. This sums all of the pixels into fewer bins, and the bins have higher values. That is the \textit{rgb} vs \textit{yuv} case, fewer vs more bins are used. To get more consistent visual feedback (and on scopes), the concept of sum was used instead of the maximum number of occurrences (max).
-
-To report something more consistent, the reported value has been changed from
-the original code to be
-the \textit{sum} of the accumulated counts for the bins reporting a pixel bar on the
-graph. The effect of this is to do this:
+The \textit{total} pixels for each value is approximately the same, but the \textit{max} value depends on the color quantization. More colors increment more bins. Fewer colors increment fewer bins. In both cases, the image size has the same number of pixels. So the pixels will distribute into more bins if you go to a higher depth color; those bins will have a lower count. The fewer color case increments the used bins, and skips the unused bins. This sums all of the pixels into fewer bins, and the bins have higher values. That is the \textit{rgb} vs \textit{yuv} case, fewer vs more bins are used. To get more consistent visual feedback (and on scopes), the concept of \textit{sum} was used instead of the maximum number of occurrences (max).
-
-\begin{figure}[htpb]
- \centering
- \includegraphics[width=0.5\linewidth]{sum.png}
- \caption{Sum bins Vs max bins}
- \label{fig:sum}
-\end{figure}
+To report something more consistent, the reported value has been changed from the original code to be the \textit{sum} of the accumulated counts for the bins reporting a pixel bar on the
\begin{center}
\begin{tabular}{clccr}
value 3.
On the right, the fine color model puts the counts into 2 bins, max 2, sum 3.
-So, by reporting the sum the shape of the results are more similar.
+So, by reporting the sum the shape of the results are more similar to Bezier.
\subsection{Histogram Bezier / Curves}%
\label{sub:histogram_bezier_curves}
\label{sub:holographictv}
\index{holographicTV}
-Incoming objects are projected like holovision seen in the movie Stars Wars as in R2-D2's video message projector of the Princess Leia. You need a movie or background image and above it a track containing the figure on which to apply the effect. This must have a transparent background. There are no configuration parameters; it only has to be applied to the upper track (figure~\ref{fig:holographictv}).
+\begin{figure}[htpb]
+ \centering
+ \includegraphics[width=0.55\linewidth]{holographictv.png}
+ \caption{Holographic messages in CinGG!}
+ \label{fig:holographictv}
+\end{figure}
+
+Incoming objects are projected like holovision seen in the movie Stars Wars as in R2-D2's video message projector of the Princess Leia (figure~\ref{fig:holographictv}). You need a movie or background image and above it a track containing the figure on which to apply the effect. This must have a transparent background. There are no configuration parameters; it only has to be applied to the upper track.
This effect originated from {\small \url{https://effectv.com}}.
-\begin{figure}[htpb]
- \centering
- \includegraphics[width=0.8\linewidth]{holographictv.png}
- \caption{Holographic messages in CinGG!}
- \label{fig:holographictv}
-\end{figure}
\subsection{Hue saturation}%
\label{sub:hue_saturation}
\label{sub:live_video}
\index{live video}
-This effect reads video directly from the capture card input. It replaces any video on the track so it is normally applied to an empty track. Only one \textit{Live Video} effect can exist at any time on the timeline. It can not be shared by more than one track. The configuration for the capture card is taken from the recording preferences. Go to \texttt{Settings $\rightarrow$ Preferences $\rightarrow$ Recording} to set up the capture card.
+This effect reads video directly from the capture card input. It replaces any video on the track so it is normally applied to an empty track. Only one \textit{Live Video} effect can exist at any time on the timeline. It can not be shared by more than one track.
+The configuration for the capture card is taken from the recording preferences. Go to \texttt{Settings $\rightarrow$ Preferences $\rightarrow$ Recording} to set up the capture card.
+There is a limitation when both Audio and Video use DV, in that you can not use this plugin at the same time as \textit{Live Audio}.
In the \textit{Video In} section where it says \textit{Record driver}, it should be set to either \textit{Video4Linux2} or \textit{IEC 61883}. Other video drivers have not been tested with Live Video and probably will not work. For live video, the selection for \textit{File} Format and \textit{Video} needs to be set to a format the timeline can use. The file format must be Quicktime for Linux and video recording must be enabled for it. Click on the wrench to set the video compression.
The video compression depends on the recording driver. For the \textit{Video4Linux2} recording driver, the compression must be \textit{Motion JPEG A}. For the \textit{IEC 61883} driver, the compression must be \textit{DV}. This gets the driver to generate output in a color model that the timeline can use. Some cards provide color and channel settings. Live video takes the color settings from the values set in the Video In window. Go to \texttt{File $\rightarrow$ Record} to bring up the recording interface and the Video In window. Values set in the Video in window are used by Live Video. Any channels the capture card supports need to be configured in the Video In interface since the same channels are used by the Live Video effect.
-With the video recording configured, highlight a horizontal region of a video track or define in and out points. Then drop the Live Video effect into it. Drop other effects after Live Video to process the live video in realtime. For best results, you should use OpenGL and a video card which supports GL shading language. Go to \texttt{Settings $\rightarrow$ Preferences $\rightarrow$ Playback $\rightarrow$ Video Out} to enable the OpenGL driver.
+With the video recording configured, highlight a horizontal region of a video track or define in and out points. Then drop the Live Video effect into it. Drop other effects after Live Video to process the live video in realtime. For best results, you should use OpenGL and a video card which supports GL shading language. Go to \texttt{Settings $\rightarrow$ Preferences $\rightarrow$ Playback $\rightarrow$ Video Out} to enable the OpenGL driver which will make it possible to process video input in real time.
\subsection{Loop video}%
\label{sub:loop_video}
\begin{description}
\item[Target Track:] you can choose between \textit{Top} and \textit{Bottom}.
- \item[Operation:] you can choose between \textit{Replace Target} (component + alpha channels); \textit{Components Only} (color channels only) and \textit{Alpha Replace} (alpha channel only)
+ \item[Operation:] you can choose between \textit{Replace Target}, \textit{Components Only} and \textit{Alpha Replace}.
+ \begin{itemize}
+ \item \textit{replace Target} (component + alpha channels), this allows you to have the ability to overwrite everything on the target track with the source track where the the plugins are inserted.
+ \item \textit{Components only} (color channels only), replace the RGB or YUV components of the target track by the RGB or YUV components of the source track. The Alpha of the target track does not change.
+ \item \textit{Alpha replace} (alpha channel only), only the Alpha of the target track is changed but the components are not. This makes it easy to create an alphs channel on a track and then use that to apply it easily to another track.
+ \end{itemize}
\end{description}
It works as a shared plugin. The typical usage scenario is to build up a possibly animated Mask in one track and then to transfer the Alpha channel to another target track.
\label{sub:swap_channels}
\index{swap channels}
-Swap R G, B, Alpha with another color channel.
+Swap color, R G B, and Alpha channels with another channel or even turn channels off completely.
\subsection{Threshold}%
\label{sub:threshold}
Videoscope summarizes intensity and color on a calibrated display. The Videoscope can be used in conjunction with other \CGG{} plugins such as \textit{Color 3 Way}, \textit{YUV}, \textit{Brightness}, \textit{Color Balance} or \textit{Histogram} to accurately correct video for contrast, clarity, conformance (to normalize various videos shot under different light settings), or for cinematic purposes. The human eye is not specialized to match precise level of light and color, but Videoscope is. Videoscope contains three displays: the waveform scope and the vectorscope, plus the histograms (figure~\ref{fig:videoscope01}). Instead of applying the plugin to the tracks/edits we want to examine, we can use the Videoscope buttons in the Composer and Viewer windows. \includegraphics[height=\baselineskip]{scope.png} In this way the monitors act on the frame indicated by the insertion point, without taking into account the stack of tracks or on which edits to apply the plugin.
+\begin{figure}[hbtp]
+ \centering
+ \includegraphics[width=1.0\linewidth]{videoscope01.png}
+ \caption{GUI of the Videoscope. You see Histogram, RGB Parade and Vectorscope}
+ \label{fig:videoscope01}
+\end{figure}
+
+When using the X11 graphics driver and RGBA-FLOAT color model, Videoscope allows you to display greater than (0 - 1.0f) values to accomodate HDR. This does not work when using X11-OpenGL because it is an 8-bit limited driver. The display will stop at -10\% or +110\%, but there is no clipping. For example, by varying the brightness all out-of-range values become visible on Waveform, even over 110\%. However you must disable the "smooth" option which always causes clipping.
+
The Videoscope menu window has many options.
\paragraph*{Scopes:} we can choose between two histograms:
\item \textit{VectorWheel}
\end{itemize}
-\begin{figure}[hbtp]
- \centering
- \includegraphics[width=1.0\linewidth]{videoscope01.png}
- \caption{GUI of the Videoscope. You see Histogram, RGB Parade and Vectorscope}
- \label{fig:videoscope01}
-\end{figure}
-
\paragraph*{Settings:} It is divided into two sections. The upper section contains two items:
\begin{description}
- \item[Smooth:] serves to make the graph more homogeneous, improving its visualization.
+ \item[Smooth:] serves to make the graph more homogeneous, improving its visualization. However, it has a side effect: in case of frames that have data in the range of 100-110\% (i.e., outside the normal range of 0-100\%, also called super-white), it causes a clip by cutting off this data and reporting only of normal data. If we don't want this clip disable Smooth.
\item[Refresh on Stop ON:] [checked -- only for Transport buttons] scopes are updated when you stop playback at a given location. Instead, they are locked at the start position while you playback. This saves system resources and makes playback smoother. By dragging the cursor the scopes are updated in realtime.
\item[Refresh on Stop OFF:] [unchecked -- for Transport buttons and dragging cursor] the display of the scopes is synchronized with the playback. Every variation of the graphs is in realtime. There may be some decrease in fps during playback.
\item[Refresh on Release:] This works for the Viewer and Compositor windows. Scopes are not updated during playback. The update occurs only when you stop playback, that is at the final position (either by dragging the cursor or using the Transport buttons). When in the timeline, if you drag on the TimeBar or reposition in the TimeBar in either Drag and Drop or Cut and Paste mode, the release of the button also will update the Scopes. This saves system resources and makes playback smoother. Because there is no update when playing in the main window, you can still easily get a videoscope update simply by moving the mouse to the Compositor and a single click there will update the scopes without changing the frame (as long as Click to Play is not enabled).
If we left-click on the graph with the mouse, we will see a crosshair that we can place exactly where we want to measure. We can read the precise values of X and Luminance (Value) in the pop-up box that appears at the bottom right (figure~\ref{fig:videoscope03}).
-The Waveform scope helps correct image light levels for contrast range or for conforming light levels on various scenes originally shot on different light settings. The same can be done with Waveform RGB or the convenient overlapping representation (Waveform Ply).
-
\begin{figure}[hbtp]
- \centering
- \includegraphics[width=1.0\linewidth]{videoscope03.png}
- \caption{Examples of waveform (with crosshair and the coordinates' box), waveform RGB and waveform Ply}
- \label{fig:videoscope03}
+ \centering
+ \includegraphics[width=1.0\linewidth]{videoscope03.png}
+ \caption{Examples of waveform (with crosshair and the coordinates' box), waveform RGB and waveform Ply}
+ \label{fig:videoscope03}
\end{figure}
+The Waveform scope helps correct image light levels for contrast range or for conforming light levels on various scenes originally shot on different light settings. The same can be done with Waveform RGB or the convenient overlapping representation (Waveform Ply).
+
\subsubsection*{Adjusting luminance}%
\label{ssub:adjusting_luminance}
projects / goodguy / cin-manual-latex.git / blobdiff