What is Flow Scale?

Flow scale defines the density of motion vectors used to generate intermediate frames. Higher values create finer patches but increase the computational load.

1. Impact

   • A higher flow scale (e.g., 100 → 4×4 patches) means smaller patches and denser motion vectors.
   • A lower flow scale means larger patches and fewer vectors.
   • Which means, higher flow scale would result in denser and more accurate motion vectors

2. Resolution Dependency

   • At high resolutions (e.g., 4K), using finer patches exponentially increases processing demands.

3. Content Dependency

   • Patch complexity varies by texture (e.g., grass vs. cement). Finer patches do not always equal better quality.

4. Performance-Quality Tradeoff

   • High Flow Scale: Better for fine, detailed motion, but may cause artifacts or choppiness if set too high.
   • Low Flow Scale: Smoother output and more efficient for large motions, but worse for fine details.

5. Critical Note

   • Adjusting the flow scale does not alter the output resolution—only the motion vector precision.

Guideline: Balance the flow scale based on the content and resolution to optimize performance and visual fidelity.

Analogy: Imagine you are driving and must judge the motion of other cars to avoid a crash. You only need basic information about each car's general shape and movement, not irrelevant details like the pattern on another driver's tie. A lower flow scale provides this essential motion data without the performance cost of processing unnecessary details, often leading to better results. This is especially true at high resolutions like 4K, 6K, etc., where the performance hit from a high flow scale is significant and often unnecessary for smooth and accurate output.

by- Sage