SAMVIQ (Subjective Assessment Method for Video Quality), defined in ITU-T P.910 section 8.5, is a multi-stimulus method that gives the viewer random access to the test material. Rather than seeing clips one at a time in a fixed order, the viewer can play several clips in any order they choose, compare them directly against an explicit reference, replay any of them, and adjust their scores until satisfied, rating each on a continuous 0-100 scale. This makes it well suited to direct multi-way comparison, where the viewer places a set of conditions relative to each other and to the reference at once. SAMVIQ is one of the continuous-scale methods, and like the others it buys fine discrimination at the cost of being harder for viewers and slower to run; P.910 cautions that for continuous and many-point scales the accuracy of the MOS does not improve while the task gets harder, the viewer anchoring to a handful of levels anyway. It is a neighbour of DSCQS, distinguished by its random-access, replayable structure.
The handbook · 7 volumes
Fora Soft Video Engineering Handbook
SAMVIQ gives viewers random access to clips and an explicit reference, which makes it useful for comparing several encodes of the same source. Our seven-volume handbook covers the full video stack; for SAMVIQ start with Volume 1, which explains subjective testing, MOS, quality metrics and how codec comparisons are run. Written by Nikolay Sapunov, CEO at Fora Soft.
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