Video Editing Motion Graphics and Visual Effects Flashcards

24 sample cards from the Motion Graphics and Visual Effects deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. What is color spill in green screen work, and how is it fixed?

   Spill is green light reflecting off the screen onto the subject's edges, hair, and skin; it is fixed with spill suppression, which desaturates or shifts the contaminated green tones so edges blend with the new background.

2. List three on-set practices that make green screen footage easier to key.

   Light the screen evenly and without wrinkles or hotspots; separate the subject several feet from the screen to reduce spill and shadows; avoid wardrobe or props that match the key color (and use adequate shutter speed to limit motion blur on edges).

3. Name the primary keying effects in Premiere Pro and After Effects.

   Premiere Pro uses Ultra Key; After Effects uses Keylight (plus tools like Key Cleaner and Advanced Spill Suppressor).

4. In matte cleanup, what do 'choke' and 'soften' do?

   Choke shrinks (or expands) the edge of the keyed matte to eliminate leftover fringe around the subject; soften blurs the matte edge slightly so the composite blends naturally with the background.

5. What is a garbage matte?

   A rough mask drawn to exclude unwanted areas outside the subject — light stands, screen edges, markers — before keying, so the keyer only has to process the usable screen area.

6. What is the difference between a mask and a matte?

   A mask is a shape (often a drawn path) applied to a layer to define which part is visible or affected; a matte is a separate image or channel whose grayscale or alpha values determine the transparency of another layer. Masks are drawn on the layer; mattes come from another source.

7. What is a track matte, and what are its two main types?

   A track matte uses one layer to define the transparency of another: an alpha matte uses the matte layer's alpha channel, while a luma matte uses the matte layer's brightness (white = opaque, black = transparent).

8. What does feathering a mask do?

   It softens the mask's edge over a gradual falloff instead of a hard boundary, helping masked elements or effects blend invisibly into the surrounding image.

9. What is rotoscoping in visual effects?

   The frame-by-frame (or tool-assisted) tracing of a subject with animated masks to isolate it from its background when no keyable screen exists, enabling selective effects or compositing.

10. What is a blend mode?

    A per-layer setting that mathematically combines a layer's pixel values with those of the layers beneath it (instead of simply covering them), producing effects like darkening, lightening, or contrast enhancement.

11. Contrast the Multiply and Screen blend modes, including their basic math on normalized pixel values $a$ and $b$.

    Multiply darkens: result $= a \times b$, so anything multiplied with black stays black and white leaves the underlying pixel unchanged. Screen lightens: result $= 1 - (1 - a)(1 - b)$, so white forces white and black leaves the underlying pixel unchanged. Multiply is used for shadows/textures, Screen for glows, flares, and light elements on black.

12. How does the Overlay blend mode behave?

    It is a contrast mode: it multiplies (darkens) where the base layer is darker than 50% gray and screens (lightens) where it is brighter, boosting contrast while preserving highlights and shadows — common for texture overlays and punchy grades.

13. How do opacity and blend modes differ when layering clips?

    Opacity uniformly fades a layer's overall transparency, mixing it evenly with layers below; a blend mode keeps the layer fully present but changes the math by which its pixels combine with underlying pixels, producing content-dependent results.

14. What is point tracking, and what does the software actually follow?

    Point tracking follows a small, high-contrast pattern of pixels (a feature region) from frame to frame inside a defined search area, generating position data (and with more points, rotation and scale) that can drive other layers or effects.

15. What do one-point, two-point, and four-point (corner pin) tracks each capture?

    One-point tracking captures position only; two-point tracking adds rotation and scale (from the changing relationship between the points); four-point corner-pin tracking maps all four corners of a plane, capturing perspective distortion for screen or sign replacement.

16. What is planar tracking, and how does it differ from point tracking?

    Planar tracking (e.g., Mocha) tracks an entire flat surface — its texture, edges, and shading — rather than individual pixel points, solving position, rotation, scale, shear, and perspective; it stays locked even when individual features blur, lack contrast, or are partially occluded.

17. When would planar tracking succeed where point tracking fails?

    On surfaces with motion blur, low contrast, partial occlusion (objects crossing in front), or no distinct trackable points — a phone screen, wall, or sign — because the tracker uses the whole plane's information instead of one small pattern.

18. What does Warp Stabilizer do in Premiere Pro/After Effects?

    It automatically analyzes a clip's motion and removes camera shake by tracking the footage, then smoothing or locking the motion — scaling, repositioning, and (if enabled) warping frames to hide the correction.

19. In Warp Stabilizer, what is the difference between the 'Smooth Motion' and 'No Motion' results?

    Smooth Motion keeps the original camera move but evens it out (for intentional but shaky moves like walking shots); No Motion attempts to remove all camera movement, simulating a locked-off tripod shot.

20. Why does stabilization usually crop or zoom into the footage?

    To counteract shake, each frame is shifted and rotated, which exposes empty gaps at the frame edges; the stabilizer scales the image up (Stabilize, Crop, Auto-scale) so those gaps stay outside the visible frame — heavier shake requires a larger zoom and thus more resolution loss.

21. What causes rolling shutter 'jello' distortion, and how is it corrected?

    CMOS sensors expose the image line by line rather than all at once, so fast motion or vibration skews and wobbles verticals; it is corrected with rolling shutter repair tools (e.g., the Rolling Shutter Repair effect or Warp Stabilizer's Rolling Shutter Ripple options).

22. Describe the basic workflow for pinning text or a graphic to a moving object in a shot.

    Track a stable feature on the object (point or planar track), apply the resulting motion data to the text layer — directly, or via a null object parented to the text — then refine position offset, add motion blur, and mask/roto anything that should pass in front of the graphic.

23. What is Adobe Dynamic Link, and what is its key advantage?

    A live connection that lets a Premiere Pro sequence contain an After Effects composition (and vice versa) without rendering intermediate files: changes saved in one app update automatically in the other, eliminating repeated exports and version mismatches.

24. What does round-tripping mean in post-production, and what is one trade-off of a linked (unrendered) workflow?

    Round-tripping is sending media from one application to another for specialized work (e.g., Premiere → After Effects for VFX via 'Replace with After Effects Composition', or → Audition for audio) and returning it to the original timeline with changes intact. The trade-off of staying dynamically linked is playback/render performance — linked comps must be computed live, so complex comps may need rendering or proxies for smooth editing.

What this deck covers

Motion Graphics and Visual Effects flashcards FAQ