\chapter{Keyframes}%
\label{cha:keyframes}
-The word \textit{keyframe} has at least 3 contextual meanings in the NLE environment. First, the oldest meaning, is the \textit{I-Frame} definition used in codecs algorithms. These are \textit{key} frames that begin a new sequence of pictures, and are anchor points for repositioning (seeks). Next are the automation parameter data points. These are usually input to primitive math forms, like translation and zoom. And last are blobs of data that are chunks of parameters to plugins that can do almost anything. The data can be a simple value, like a fader value, or more complex like a group of points and colors in a sketcher plugin keyframe. The word keyframe has changed a lot in meaning. In the context of Cinelerra, keyframes are data values that have been associated to the timeline which affect the media presentation. So a keyframe no longer refers to a frame, but to a position on the timeline.
+The word \textit{keyframe} has at least 3 contextual meanings in the NLE environment. First, the oldest meaning, is the \textit{I-Frame} definition used in codecs algorithms. These are \textit{key} frames that begin a new sequence of pictures, and are anchor points for repositioning (seeks). Next are the automation parameter data points. These are usually input to primitive math forms, like translation and zoom. And last are blobs of data that are chunks of parameters to plugins that can do almost anything. The data can be a simple value, like a fader value, or more complex like a group of points and colors in a sketcher plugin keyframe. The word keyframe has changed a lot in meaning. In the context of \CGG{}, keyframes are data values that have been associated to the timeline which affect the media presentation. So a keyframe no longer refers to a frame, but to a position on the timeline.
-In Cinelerra, there are two general types of keyframe data, \textit{automation keyfra\-mes} (autos) which are drawn as colored lines and box icons overlayed at a point on a media track, and \textit{plugin keyframes} which are drawn as gold key symbols on a plugin bar of a track. \quad
+In \CGG{}, there are two general types of keyframe data, \textit{automation keyfra\-mes} (autos) which are drawn as colored lines and box icons overlayed at a point on a media track, and \textit{plugin keyframes} which are drawn as gold key symbols on a plugin bar of a track. \quad
\includegraphics[height=\baselineskip]{images/auto.png}
Auto $\leftarrow$ Keyframe $\rightarrow$
Plugin \includegraphics[height=\baselineskip]{images/plugin.png}
Usually, the use of the keyframe values are more pleasing when the data varies smoothly between keyframe anchors on the timeline. This is useful in many cases that are familiar, like a video fade in/out, or audio pan between channels. To make the auto value change smoothly as the media is played, the keyframes auto values are points on curves that are created according to the design of the effect. Most of the primitive types can create anchor points on curves that are piecewise linear, smooth, sloped, or broken at the keyframe anchor points.
-Curve smoothing is called \textit{interpolation} and it uses keyframe point values and control values that determine how the curve will react at the time the media is played or rendered. Interpolation uses 2 keyframes to create a set of intermediates which are used as active values between the \textit{previous} and \textit{next} keyframe anchors on the timeline. The way the intermediate data is generated depends on the type of curve used to invent these values. Cinelerra interpolates the intermediate values making the change happen smoothly and gradually over time. The simple linear mathematical formula for interpolation is: $a\times(1-t) + b\times t$ where $0\le t\le 1$ uniformly.
+Curve smoothing is called \textit{interpolation} and it uses keyframe point values and control values that determine how the curve will react at the time the media is played or rendered. Interpolation uses 2 keyframes to create a set of intermediates which are used as active values between the \textit{previous} and \textit{next} keyframe anchors on the timeline. The way the intermediate data is generated depends on the type of curve used to invent these values. \CGG{} interpolates the intermediate values making the change happen smoothly and gradually over time. The simple linear mathematical formula for interpolation is: $a\times(1-t) + b\times t$ where $0\le t\le 1$ uniformly.
\section{Using Autos}%
\label{sec:using_autos}
\section{Compositor Keyframes}%
\label{sec:compositor_keyframes}
-Camera and projector translation is represented by two parameters: \textit{x} and \textit{y}, making it difficult to adjust with curves. Cinelerra solves this problem by relying on automatic keyframes. With a video track loaded, move the insertion point to the beginning of the track and enable automatic keyframe mode. Move the projector slightly in the compositor window to create a keyframe. Then go forward several seconds. Move the projector a long distance to create another keyframe and emphasize motion. This creates a second projector box in the compositor, with a line joining the two boxes. The joining line is the motion path. If you create more keyframes, more boxes are created. Once all the desired keyframes are created, disable automatic keyframe mode.
+Camera and projector translation is represented by two parameters: \textit{x} and \textit{y}, making it difficult to adjust with curves. \CGG{} solves this problem by relying on automatic keyframes. With a video track loaded, move the insertion point to the beginning of the track and enable automatic keyframe mode. Move the projector slightly in the compositor window to create a keyframe. Then go forward several seconds. Move the projector a long distance to create another keyframe and emphasize motion. This creates a second projector box in the compositor, with a line joining the two boxes. The joining line is the motion path. If you create more keyframes, more boxes are created. Once all the desired keyframes are created, disable automatic keyframe mode.
Dragging the auto curve with tweaking off, adjusts the previous keyframe. With tweaking on, if no keyframe is at the timeline position, then a new one is created at that position and the modification value is applied. If you are halfway between two keyframes, the first projector box is adjusted while the second one stays the same. The video does not appear to move in step with the first keyframe. This is because halfway between two keyframes, the projector translation is interpolated. In order to set the second keyframe you will need to move after the second keyframe.
projects / goodguy / cin-manual-latex.git / blobdiff