Lyric Masked Time
The Lyric Masked Time filter is an unusual stylistic effect that time-delays individual pixels in the source video based on the gray-scale values of a mask you provide to the filter. It is most-commonly useful with locked-down shots in which only certain features are moving, and will distort or diffuse the moving features depending on the mask and the movement and the selected time delays.
The example above left shows a lamp moving towards frame top with a random-strands mask, causing the lamp break into a diffuse fragment trail as it moves. The samples on the right show a person walking, in the top case with a gradient mask that distorts the moving legs and in the botton with a random horizontal lines mask that feathers the motion. In all cases, the source pixels over the black areas in the mask are delayed most, those over the white areas are delayed least.
The filter provides controls for selecting and modulating the mask, easing in and out of the effect, setting the compositing mode for the delayed pixels, and performing sub-frame or sub-field blending to smooth the distortion-style effects.
The Lyric Masked Time filter includes a set of effect controls that are common across all Lyric effect filters. For a detailed description of these controls, please see the Common Effect Controls documentation.
Additionally, all Lyric Effect filters can be applied through mattes or masks to constrain the filter effect to particular areas of the image. For background information on mattes and masks, please refer to the Lyric Matte Primer.
The Maximum Delay slider sets the delay in frames for pixels underlying black areas in the mask. Recall that the greyscale levels in the mask determine the delay of corresponding pixels, pixels over black mask areas will be delayed by the slider setting, pixels over middle-gray mask areas will be delayed by half that number of frames, and pixels over white mask areas are taken from the current frame, with in-between values scaled appropriately.
The Frame Blend Level dropdown menu controls sub-frame blending. It can be set to None, meaning no frame blending, the closest frame is used, 2x meaning 2 subsamples, 4x, or 8x meaning 4 and 8 subsamples respectively. If the video is interlaced, the subframe sampler will subsample from the nearest de-interlaced field, improving smoothness over simple frame-blending. Note that frame-blending is most appropriate for distortion-style effects with gradient masks and increasing the frame-blend level can increase rendering times.
Field Processing tells the filter if the video is interlaced and, if so, what the field-dominance is. Setting this correctly is important for producing the smoothest rendered video. Use Lower (Even) for DV footage and Upper (Odd) for HDV interlaced footage, for example, and None for progressive-frame footage.
The delayed pixels are composited over the current frame using the compositing mode selected in the Composite Mode dropdown menu.
Enabling Fade Over Delay causes the delayed pixels to be made gradually transparent in proportion to their delay, so that the most delayed (over black mask areas) are fully-transparent. This can have the effect of producing a gradual trail for diffuse-style effects.
The Ease In and Ease Out sliders can be used to gradually bring on the time-delay effect or gradually reduce the delay effect. Larger ease values increase the ramp up and down times. This is useful if the filter is applied to a clip with objects in continuous motion; adding an ease-in will prevent a jump to the fully-delayed effect, and adding an ease-out will cause all the delayed pixels to "catch-up" to real time by the end of the clip or filter range.
The Mask Controls section contains controls for selecting and managing the time-delay mask. The Mask Source dropdown specifies the source of the time-delay mask.
The Mask Image options use either the luminance or alpha-channel of the image or clip dropped onto the Mask Image/Clip well. (Tip: the Photoshop Textures directory is a good source of masks for this filter.)
Source Alpha uses the alpha-channel currently in the source video, which, you recall, can be supplied by a matte filter placed above the Masked Time filter.
Noise, Horizontal Gradient and Vertical Gradient are just easy-to-hand, general-purpose masks that may be of use getting a time-warp effect started.
Invert flips the luminance values in the mask, Diffuse adds small, random offsets to the mask pixels, breaking up smooth edges, and and applies a softening blur. These can all be used to fine-tune the effect once the mask is in place.
The Effect Controls section is a set of common controls that are documented on the Common Effect Controls page. They can be used to achieve masked and other specialized filter effects.