Temporal pooling is the step that combines a metric's per-frame scores along the time axis into the single number for a clip, as opposed to spatial pooling, which combines per-pixel scores inside one frame. Once each frame has a single score, temporal pooling decides how those scores along time are summarized. The default is the arithmetic mean, but it smooths over brief bad stretches, so a one-second collapse vanishes into a sea of good frames. Because research shows people weight the worst, transient moments far more than the average, worst-case temporal rules track human opinion better: a low percentile such as perc5 or perc10 reports how bad it gets for a noticeable stretch, while the minimum or a windowed minimum flags the single worst frame or worst short window. A related human effect, recency, means a drop near the end of a long session costs more, which standardized streaming models such as ITU-T P.1203 build into their temporal integration. Temporal pooling sits beside spatial pooling and shares the same averaging trap one level up.
The handbook · 7 volumes
Fora Soft Video Engineering Handbook
Temporal pooling decides whether a two-second glitch shows up in a clip's score or disappears into the average. Our seven-volume handbook covers the full video stack; for temporal pooling begin with Volume 1, which explains per-frame VMAF and SSIM, pooling choices such as percentiles and minimums, and comparing encodes fairly. Written by Nikolay Sapunov, CEO at Fora Soft.
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