Summary of what Wave 5 landed in the 0.1.5 cycle. Source pointers are relative to the repository root.

• TranscodePipeline::execute() in crates/oximedia-transcode/src/pipeline.rs (line 1165). Constructs an internal Pipeline from the stored PipelineConfig and drives it to completion. The companion TranscodePipelineBuilder supplies the fluent construction API.
• MultiTrackExecutor<M: Muxer> in crates/oximedia-transcode/src/multi_track.rs (line 285) — DTS-ordered multi-track interleaving for synchronous mux of video / audio / subtitle tracks.

Pure-Rust, no FFI:

• crates/oximedia-transcode/src/hw_accel/macos.rs: probe_macos() reads sysctl -n hw.optional.arm64 and machdep.cpu. brand_string, identifies M1/M2/M3/M4 or Intel Mac, and returns a HwAccelCapabilities with the VideoToolbox codec matrix (M3/M4 adds AV1 decode).
• crates/oximedia-transcode/src/hw_accel/linux.rs: probe_linux() walks /sys/class/drm/, reads PCI vendor IDs (0x8086 Intel, 0x1002 AMD, 0x10de NVIDIA) via std::fs::read_to_string, and emits per-card codec capabilities. No libva, no DRM ioctls.
• Shared capabilities.rs type (HwAccelCapabilities, HwAccelDevice, HwKind) consumed by the transcode pipeline to pick hardware codecs.

• crates/oximedia-net/src/abr/bba1.rs implements Huang et al. SIGCOMM 2014 "A Buffer-Based Approach to Rate Adaptation" with three-zone variant selection:
  • Reservoir [0, r] → lowest variant.
  • Cushion (r, r+c] → linear-interpolate variant index.
  • Above-cushion (r+c, ∞) → highest variant.
• BbaParams::default() (B=30 s, r=10 s, c=20 s) matches the paper; BbaParams::low_latency() (B=10 s, r=2 s, c=8 s) for live streaming.
• select_variant(buffer_level, &params, &variants) -> usize is a stateless pure function — no controller object required.

• crates/oximedia-container/src/mux/mpegts/scte35.rs emits ad-marker PES payloads with MPEG-2 CRC-32:
  • emit_splice_null() (line 182) — heartbeat.
  • emit_splice_insert(&SpliceInsertConfig) (line 238) — ad-break in/out with PTS.
  • emit_time_signal(pts: Option<Duration>) (line 160) — programme signalling.
• crates/oximedia-container/src/demux/mpegts/scte35.rs parser: Scte35Parser (line 258) parses the same payloads back into typed events.
• crates/oximedia-container/src/metadata/batch.rs introduces BatchMetadataUpdate (line 111) — container-agnostic in-place tag updates on MP4 / MKV / FLAC / Vorbis metadata without rewriting the whole file.

• crates/oximedia-core/src/error_context.rs — structured error chains:
  • ErrorFrame (line 94) — one frame in the chain (file, line, function, message).
  • ErrorContext (line 234) — owns a Vec<ErrorFrame>, emitted as the trace when an error propagates.
  • ErrorChain (line 406) — iterator over the full chain.
  • ErrorContextBuilder (line 494) — fluent construction.
• crates/oximedia-core/src/codec_negotiation.rs — decoder/encoder format selection:
  • FormatCost trait (line 699) — cost function abstraction.
  • FormatNegotiator<'a, F> (line 874) — negotiates a preferred pixel/sample format pair between source and sink, minimising cost.

Docs round 3: codec_status.md (unchanged since Action A), rate_control.md, simd_dispatch.md, and this file.

• oximedia-transcode: 1174 tests pass.
• oximedia-net: 1606 tests pass.
• oximedia-container: 1282 tests pass, 65 skipped.
• oximedia-core: 1022 tests pass.
• Zero clippy warnings on all four crates.

No source behaviour changed in Slice F — documentation only.