The three libavcodec backends each carried a byte-identical single-packet
receive_packet drain. Move it once into the shared Tier-2 glue as
poll_encoder -> PollOutcome (the richest form: Packet / Again / Eof), and
have the callers narrow it:
- Linux NVENC (encode/linux/mod.rs): poll() matches the shared fn, collapsing
Again|Eof to Ok(None) — was an inlined match, now one call.
- VAAPI (encode/linux/vaapi.rs): drop the local poll_encoder; the blocking
budget loop lets Again|Eof fall through to the deadline check, byte-identical
to the old Option::None path.
- Windows AMF/QSV (encode/windows/ffmpeg_win.rs): drop the local PollOutcome +
poll_encoder; its deadline-driven drain already matches PollOutcome, so only
the import changes.
No behavior change on any backend. Still a plain monomorphic free fn over a
borrowed &mut Encoder — no new per-frame dyn/Box/alloc; the only allocation is
the same bitstream to_vec() each path already made. Drops the now-unused
ffmpeg::Packet import from all three.
Linux check + clippy green (nvenc,vulkan-encode,pyrowave) on RTX 5070 Ti;
ffmpeg_win.rs is Windows-cfg, pending .173 compile.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
enricobuehler
fd8a062e2c