Ettore Di Giacinto a2a71158ed backend(audio-cpp): map NaN PCM samples to silence explicitly ...

f32_to_s16le relied on std::min argument order to keep a NaN sample away from
std::lround, whose result is unspecified for NaN. That was too subtle to rest on
a comment, and the comment was itself wrong: it warned against a spelling that
the outer std::max already catches, while three real spellings leak, including
std::clamp, which is the idiomatic C++17 way to write the same clamp and so the
likeliest future edit.

Divert NaN before the clamp and encode it as 0. A NaN sample rendered as a
full-scale click is worse audio than a dropped one, and this unit converts audio
that may have originated off the wire.

Pin it with an exact-value check rather than a range check, since all three
outcomes the plausible spellings produce are finite and inside full scale, plus
an invalid-operation check that fails unless the NaN is diverted before any
ordered comparison. That second check is what catches modernizing the clamp and
dropping the guard together.

Also bound the seconds round-trip comment, which claimed unconditionally what
holds only below roughly 2^23 samples, and document NaN, saturation and that
bound in the header.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

2026-07-26 00:12:49 +00:00

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