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effectcraft/crates
vangel76andClaude Sonnet 5.5 c82633c8d7 av1enc: find the first frame's quantizer in fewer passes
Bitrate mode coded the first frame four times with a fixed gain. Now the
first pass still gets the old correction (30 quantizer steps per halving
of the size, which fits the starting range), and from the second
correction on the next quantizer is placed in the log domain of the
quantizer step, where the frame size is close to a line: false position
between the nearest passes that enclose the target, otherwise a secant
step with the measured slope. The search stops as soon as the size is
within 3 % of the target, when no untried quantizer is left between the
enclosing passes, or when it would repeat a quantizer (a target the
content cannot reach, where the old code coded the same frame at the
lowest quantizer up to four times). At most four passes remain.

The first frame is within 3 % of the target on the same cells as before
and nearer to it on most of the others; two cells where the size jumps
by a factor of 4 or more between neighbouring quantizers (noisy content)
land further away than with the old search. Total passes over the 28
test cells: 112 -> 70.

Part of #2390

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
2026-10-25 13:38:38 +01:00
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2026-10-18 09:35:33 -04:00
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