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Frame Blending & Transitions

Exaplay 3 supports GPU-accelerated frame blending between clips on the same track and flexible transition effects at clip boundaries.

Crossfade (Overlap Transition)

The simplest transition is a crossfade: overlap two clips on the same track and Exaplay blends between them over the overlap duration.

Two clips overlapping with alpha curves at the crossfade region

The overlap length determines the crossfade duration. Adjust it by dragging either clip edge in the Timeline.

Transition Types

Set the transition type for each clip in the Inspector → Transitions section.

In Transition

Applied when the clip enters (fades in or appears).

TypeDescription
CutNo transition — clip appears immediately
CrossfadeAlpha blend from 0 to 1 over the overlap
Wipe → LeftContent wipes in from the right edge
Wipe → RightContent wipes in from the left edge
Wipe ↑Content wipes in from the bottom
Wipe ↓Content wipes in from the top
Fade to BlackFades out the outgoing clip to black, then fades the new clip in

Out Transition

Mirror of the In Transition, applied as the clip exits.

Transition Duration

Transition durations are determined by the overlap length between adjacent clips. You can also set them numerically in the Inspector:

  • In Duration — length of the fade-in (seconds)
  • Out Duration — length of the fade-out (seconds)

Frame Blending

Frame blending smooths slow-motion or speed-changed clips by blending adjacent source frames together, reducing the stroboscopic effect of frame repetition.

Enable it per-clip in Inspector → Playback → Frame Blend.

ModeDescription
OffNo blending — each frame is held until the next
MixAdjacent source frames are averaged (50/50 alpha blend)
Optical FlowMotion-estimated intermediate frames (GPU-intensive)

Performance note: Optical Flow frame blending uses additional GPU shader passes. On complex 4K content it can reduce available frame budget. Use Mix for most cases.

Alpha Channels

Clips with alpha channels (HAP Alpha, NotchLC, PNG) blend their alpha through the normal compositing stack. The blend mode in the Inspector controls how each layer's alpha interacts with layers beneath it:

Blend modeBehaviour
NormalStandard alpha over compositing
AddPixel values added — good for light, fire, glows
MultiplyPixel values multiplied — good for shadows, darkening
ScreenInverse multiply — good for bright elements

Common Recipes

Hard Cut Between Two Videos

  • Set In Transition: Cut and Out Transition: Cut on both clips.
  • Avoid any overlap between clips.

Slow Logo Fade-In Over Background

  • Place logo (PNG with alpha) on Track 2, background video on Track 1.
  • Set In Transition: Crossfade, Duration: 3.0 s on the logo clip.

Black Between Acts

  • Set Out Transition: Fade to Black, Duration: 2.0 s on the outgoing clip.
  • Set In Transition: Crossfade, Duration: 2.0 s on the incoming clip.
  • Leave a gap between them on the timeline; the black frames fill the gap.

Exaplay 3 User Documentation