NVIDIA / NVIDIA/cosmos-framework
Clarification on shared vs. independent flow timesteps for video and action
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Since Aug 19, 2026.
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Description
Hi Cosmos team,
Thanks for releasing Cosmos 3 and the training code. I have a question about the flow timestep sampling for joint video-action training.
The technical report states that noise levels are sampled independently for each modality. However, in the current code, when independent_action_schedule=False, the action sigma/timestep appears to reuse the vision sigma/timestep:
sigmas_for_action = sigmas if sigmas_action is None else sigmas_action
and the default configuration seems to set:
independent_action_schedule: false
Could you please clarify:
Were the released Cosmos 3 action/mid-training checkpoints trained with independent video/action timesteps (independent_action_schedule=True) or with shared timesteps?
Is the default False setting intentional for post-training only, or does it also reflect the original mid-training setup?
Thanks for the clarification!
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