The libav NVENC path carried its own inline copy of the split decision and had
already drifted from the direct-SDK selector: it hard-coded a 2-way split
regardless of engine count, and had no depth rule at all. That is the drift the
shared resolver was extracted to prevent, and the copy quietly reintroduced it.
Routing it through `resolve_split_mode` needed the policy to MOVE. `nvenc_core`
is gated on `feature = "nvenc"`, but the libav path is precisely the build where
that feature is OFF (`PUNKTFUNK_NVENC_DIRECT=0`, and the featureless packages --
the packaging gap this project has been bitten by before). So
resolve_split_mode / max_forced_split_mode / clamp_to_engines, plus a new
`forced_split_width`, now live in `codec.rs`, which is always compiled and
already owned SPLIT_FORCE_PIXEL_RATE.
That means the NV_ENC_SPLIT_ENCODE_MODE values had to be hand-written as plain
constants, since the SDK enum does not exist without the feature. They are
therefore pinned: `nvenc_split_constants_match_the_sdk` (feature-gated, the only
place both are visible at once) asserts all five against the real enum, so the
copies cannot rot.
⚠ Only the FORCED outcomes are actionable on the libav side -- libavcodec's
`split_encode_mode` AVOption is its own vocabulary and our DISABLE is the NVENC
enum's 15, which would be meaningless there. DISABLE/AUTO both map to "leave the
option unset", which is exactly today's behaviour (unset = the driver's auto).
`engines = 0` ("not probed") maps to 2-way, preserving what that site always did;
a 3-NVENC part gets the wider split only on the direct-SDK path, which is the one
that actually probes.
⚠⚠ VERIFICATION GAP: .133 went down mid-change (no ping), so the WINDOWS leg is
UNVERIFIED. This matters more than usual -- the Windows backend imported
resolve_split_mode from nvenc_core and that import had to move too, which a grep
caught rather than a compiler. Re-run before trusting it:
cargo clippy -p pf-encode --features nvenc --all-targets -- -D warnings
Verified .21: clippy -D warnings clean BOTH with and without the nvenc feature
(the featureless build is the whole point of the move) and with
nvenc,vulkan-encode; 65 unit tests incl. the new constant-parity test; 25/25
NVENC on-hardware; punktfunk-host clippy clean. fmt clean.
enricobuehler
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