Problem

In helper.py:30, an assert statement is used for input validation:

assert frames.ndim == 4, f"{frames.ndim=}, expected (N, C, H, W)"

Assert statements can be disabled with python -O flag, which would silently skip validation.

Suggested Fix

Replace with explicit ValueError:

if frames.ndim != 4:
    raise ValueError(f"frames.ndim={frames.ndim}, expected 4 (N, C, H, W)")

Note

I already submitted PR #50 for this fix before creating this issue - apologies for not following the proper contribution process. Happy to close the PR if you'd prefer to discuss first.