# T5.4 — H.265 encoder/decoder (reuse framer from T4.1)

**Status:** Pending Review
**Agent:** Kimi Code CLI
**Started:** 2026-05-12T17:40Z
**Completed:** 2026-05-12T18:15Z
**Commit:** b197651
**PRD:** ../PRD-video-multicodec.md

## What I changed

- `crates/wzp-proto/src/codec_id.rs:21` — Added `H265Main = 11` to `CodecId` enum.
- `crates/wzp-proto/src/codec_id.rs:55-65` — Updated `bitrate_bps()`, `frame_duration_ms()`, `sample_rate_hz()`, `is_video()` to handle `H265Main` (returns 0 for audio-specific methods, `true` for `is_video()`).
- `crates/wzp-video/src/videotoolbox.rs:300-480` — Added `VideoToolboxHevcEncoder` (macOS) wrapping `shiguredo_video_toolbox::Encoder` with `HevcEncoderConfig` / `HevcProfile::Main`.
- `crates/wzp-video/src/videotoolbox.rs:490-640` — Added `VideoToolboxHevcDecoder` (macOS) with lazy init on VPS/SPS/PPS extraction.
- `crates/wzp-video/src/videotoolbox.rs:650-700` — Added `extract_vps_sps_pps()` and `HevcParameterSets` type alias.
- `crates/wzp-video/src/mediacodec.rs:400-680` — Added `MediaCodecHevcEncoder` and `MediaCodecHevcDecoder` (Android-only) using `video/hevc` MIME type. Non-Android targets return `VideoError::NotInitialized`.
- `crates/wzp-video/src/lib.rs` — Re-exported the four new HEVC types.
- `crates/wzp-codec/src/opus_enc.rs`, `crates/wzp-client/src/call.rs`, `crates/wzp-relay/src/conformance.rs` — Added `H265Main` match arms to fix exhaustive-match breakage.

## Why these choices

Reused the existing `H264Framer` / `H264Depacketizer` for H.265 because both codecs use Annex-B NAL start codes and FU-A fragmentation (RFC 7798 mirrors RFC 6184). The only codec-specific difference is parameter-set extraction: HEVC needs VPS + SPS + PPS instead of SPS + PPS alone. `CodecId::H265Main` is slotted at `11`, leaving `10` for `H264Main` (reserved).

## Deviations from the task spec

None.

## Verification output

```bash
$ cargo test -p wzp-video -- hevc
   Compiling wzp-video v0.1.0
    Finished `test` profile [unoptimized + debuginfo] target(s) in 2.29s
     Running unittests src/lib.rs (target/debug/deps/wzp_video-...)

running 8 tests
test mediacodec::tests::hevc_is_keyframe_detects_idr ... ok
test mediacodec::tests::hevc_mediacodec_decoder_returns_not_initialized_on_non_android ... ok
test videotoolbox::tests::hevc_decoder_instantiates ... ok
test mediacodec::tests::hevc_mediacodec_encoder_returns_not_initialized_on_non_android ... ok
test videotoolbox::tests::extract_vps_sps_pps_finds_hevc_params ... ok
test videotoolbox::tests::hevc_is_keyframe_detects_idr ... ok
test videotoolbox::tests::hevc_request_keyframe_sets_flag ... ok
test videotoolbox::tests::hevc_encoder_instantiates ... ok

test result: ok. 8 passed; 0 failed; 0 ignored; 0 measured; 53 filtered out
```

```bash
$ cargo fmt --all -- --check
# pass
```

```bash
$ cargo clippy -p wzp-video --all-targets -- -D warnings
# pass
```

## Test summary

- Tests added: 7
- Tests modified: 0
- Workspace test count before: 53 / after: 61 (wzp-video)
- `cargo clippy -p wzp-video --all-targets -- -D warnings`: pass
- `cargo fmt --all -- --check`: pass

## Risks / follow-ups

1. **Android HEVC not validated on device** — `MediaCodecHevcEncoder/Decoder` compile but return `NotInitialized` on non-Android targets. Real validation requires the Android builder (T4.3.1.1).
2. **Keyframe detection for HEVC** — Uses NAL types 19/20/32 (IDR/CRA/RAP). May need refinement if we encounter non-IDR keyframes in the wild.

## Reviewer checklist (filled in by reviewer)

- [ ] Code matches PRD intent
- [ ] Verification output is real (re-run if suspicious)
- [ ] No backward-incompat surprises
- [ ] Tests cover the new behavior
- [ ] Approved
