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A top-down view into a stairwell. A clap fires off echoes that bounce back from far above and far below in long vertical reflections.

C1-3-24 Steady State · sound_persistence principle: Echo (Wave)
Seedance 2.0ByteDance · proprietary
Kling 3.0 OmniKuaishou · proprietary
Veo 3.1Google · proprietary
LTX-2.3Lightricks · open
Ovi 1.1character.ai · open
JavisDiT++JavisDiT · open
MagiHumanGAIR-NLP · open
Per-prompt rubric

Basic standards

Visual presence

  • a stairwell

Event: a clap occurs in a stairwell

Audio presence

  • a clap

Sound: a hand clap

Key standards

Visual physical commonsense (V-PC)

  • A top-down stairwell shaft is clearly visible with stair flights and railings stacked vertically.
  • A single hand clap is performed inside the stairwell during the clip.

Audio physical commonsense (A-PC)

  • The clap is followed by discrete vertical echo reflections with long inter-reflection delays.
  • The echo reflections sound consistent with a tall narrow vertical shaft.

Cross-modal physical commonsense (AV-PC)

  • The initial clap transient in the audio aligns in time with the visible clap action.
  • The long vertical echoes follow the single visible clap as its consequence.