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A hiker stands at the edge of a mountain valley and shouts loudly across it. A quieter, slightly duller echo of the shout returns from the far cliff.

C1-3-20 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 hiker
  • a mountain valley

Event: a hiker shouts across a mountain valley

Audio presence

  • a hiker

Sound: a human shout

Key standards

Visual physical commonsense (V-PC)

  • A single hiker is shown shouting across the open space.
  • The setting is a mountain valley or canyon with the opposite cliff or ridge clearly visible.

Audio physical commonsense (A-PC)

  • A quieter and duller copy of the shout returns in the audio after a clearly perceptible delay.
  • The returning sound is a discrete copy of the original shout's content with reduced amplitude and dulled high frequencies.

Cross-modal physical commonsense (AV-PC)

  • The original shout onset aligns in time with the visible shouting action of the hiker.
  • A discrete delayed echo of the shout follows the original shout in the audio track.