+The usual steps to use Proxy are:
+\begin{enumerate}
+ \item Check that \textit{File Format} is set to \texttt{FFMPEG}.
+ \item Check or uncheck the \textit{Rescaled to project size} (FFMPEG only). The difference with this option will be explained here \ref{sub:rescaled_project_size_works}. But for old computers checking \textit{Rescaled to project size} is not recommended; again due to requiring more CPU. You need to know that when \textit{Rescaled to project size} is unchecked some Effects/Plugins do not work as expected because they use pixel values instead of percentage values as is used in the Project Format. For example \textit{Title}, \textit{Blur}, \textit{Sketcher} plugins do not work right if unchecked, while \textit{Perspective} and \textit{Crop\&Position} plugins work correctly for both checked and unchecked.
+ \item Choose the \textit{Scale factor}. The options may be different if \textit{Rescaled to project size} is checked or unchecked. The smaller the \textit{Scale factor} is, the smoother playing on the Timeline will be ($\frac{1}{8}$ is smaller than $\frac{1}{4}$), but on the Viewer/Compositor the image will be degraded/pixelated more.
+ \item Set the \textit{File Type} in the \textit{File Format} for FFMPEG, such as mp4, mpeg, or mov. Still images like jpg, tiff, and png will be converted to PNG files with alpha channel if it had an alpha channel.
+ \item Click on the wrench icon to configure video compression; just use the default values if you are unsure and prefer not to experiment.
+ \begin{enumerate}
+ \item Select the Compressor type (codec).
+ \item Change Bitrate, or Quality, and Pixels. Because not all codecs use the alpha channel for transparency, check that the letter "\textbf{a}" is in the Pixels name (such as yuv\textbf{a}420p or rgb\textbf{a}) to retain the alpha channel.
+ \item Click on the OK button to close the Compressor window.
+ \end{enumerate}
+ \item Now click on the \texttt{OK} button to start the rendering for the proxy.
+ \item Look in the lower right corner of the main window where there is a progress bar and a percentage value showing the progress of the creation of proxies, and in the lower left corner there is the \textit{Creating proxy files... ETA: hh:mm:ss} text with the "Estimated Time of Arrival (completion)" in hours, minutes, seconds. Depending on how many files your project uses, the file size, which codec is used, the scale factor, and cpu performance, creating proxies may take some time.
+\end{enumerate}
+
+You will know that Proxy mode is enabled because:
+\begin{itemize}
+ \item A white colored \textbf{P} meaning \textit{\textbf{P}roxy}, or a white colored \textbf{S} meaning \textit{Proxy \textbf{S}caled} icon is shown in the upper right corner of the main window to the left of the FF icon. If using the Cakewalk or Neophyte theme it will be a \textbf{Ps} icon.
+ \item The Proxy folder in the Resources window has been populated with the names and/or icons of the proxy media.
+ \item The edit title bar in the timeline will have the name of the proxy file instead of the original name. So if the video filename is \texttt{VID\_20221012.mp4}, the Proxy Scale Factor is $\frac{1}{4}$, and the Proxy container is mov, then the proxy name will be \texttt{VID\_20221012.proxy4-mp4.mov}.
+\end{itemize}
+
+The Proxy icon is a toggle button so that you just click on the icon to change modes. Or it can be toggled using the \texttt{Ctrl+R} shortcut.
+
+\begin{table}[ht]
+ \centering
+ \begin{tabular}{|p{2.5cm}|p{3.2cm}|p{3.2cm}|p{3.2cm}|}
+ \hline
+ {\footnotesize\textbf{Proxy State}} & {\footnotesize\textbf{Rescaled to project size (FFMPEG only)}} & {\footnotesize\textbf{Proxy icon for themes:
+ Cakewalk/ Neophyte}} & {\footnotesize\textbf{Proxy icon for themes: the Others}}\\
+ \hline
+ {\footnotesize{Off}} & {\footnotesize{checked/ unchecked}} & {\footnotesize{no icon}}
+ & {\footnotesize{no icon}}\\
+ \hline
+ {\footnotesize{Active (Enable)}} & {\footnotesize{checked}} & {\footnotesize{Ps: P(green) s(white)}}
+ & {\footnotesize{S (white)}}\\
+ \hline
+ {\footnotesize{Disable}} & {\footnotesize{checked}} & {\footnotesize{Ps: P(red) s(white)}} & {\footnotesize{S (gray)}}\\
+ \hline
+ {\footnotesize{Active (Enable)}} & {\footnotesize{unchecked}} & {\footnotesize{Ps: P(green) s(red)}} & {\footnotesize{P (white)}}\\
+ \hline
+ {\footnotesize{Disable}} & {\footnotesize{unchecked}} & {\footnotesize{Ps: P(red) s(red)}} & {\footnotesize{P (gray)}}\\
+ \hline
+ \end{tabular}
+ \caption{list States of the Proxy icon}
+\end{table}
+
+When you disable Proxy using the toggle button for Proxy, or its shortcut (\texttt{Ctrl+R}), in the Proxy Settings window you will see the \textit{Scale Factor = 1}, but if you look at the Active Scale and the State, you can understand what your setting is.
+Proxy can have three possible States: Off, Active, Disabled. The difference between Off and Disabled is that Disabled means you have set the Proxy and it is temporarily switched off (and you can see the icon in the upper right corner of the main window); you can enable proxy by just clicking on the icon, so the State will then be changed from Disabled to Active.
+
+\subsection{How Rescaled to project size (FFMPEG only) works}%
+\label{sub:rescaled_project_size_works}
+
+\begin{itemize}
+ \item When \textit{Rescaled to project size (FFMPEG only)} is checked, the size of the video data to be computed will always be the same as the Project Format. The size of your video is scaled down to the \textit{Scale factor} BUT then it is rescaled up to the Project Format. For example, your Project Format is 1920x1080 and Proxy's Scale factor is $\frac{1}{4}$, then your videos ($1920x1080$) will be scaled down to 480x270 and then up-scaled to $1920x1080$. All the Effects/Plugins work correctly because the original resolution/geometry/size is not changed. For an old computer, this option is not recommended.
+ \item When \textit{Rescaled to project size (FFMPEG only)} is UNchecked, the size of the video data to be computed will be reduced to the \textit{Scale factor}. The size of your video is scaled down to the \textit{Scale factor}. For example, your Project Format is 1920x1080 and Proxy's Scale factor is $\frac{1}{4}$, then your videos ($1920x1080$) will be scaled down to $480x270$. It works as if the Project Format were $480x270$ (and really it works). If you take a look at \texttt{Settings $\rightarrow$ Format...} when Proxy is enabled (Active), you can see that the Width and Height are changed according to the \textit{Scale factor}; you absolutely must NOT change these values! The good thing is that your computer will be faster. The bad thing is that some Effects/Plugins do not work as expected because they use pixel units. Examples are \textit{Title} and \textit{Blur} plugins. A workaround is needed for that, such as using Inkscape to create a title and export it to PNG that you load instead of using the \textit{Title} plugin.
+
+\end{itemize}
+
+Note: the dimensions of the frame/image are downscaled to the Scale factor; so if the Scale factor is $\frac{1}{4}$ and the dimension of the image is $4288x2848$ pixels, that image will be downscaled to $1072x712$. It doesn't matter what the Project Format is.
+
+\subsection{Using proxy}%
+\label{sub:using_proxy}