# iso-bmff — roadmap
Freestanding ISOBMFF/MP4. Workspace index: [`docs/roadmap.md`](../../../docs/roadmap.md).
## Stages
### 1 — fMP4 + stbl demux
- [x] Typestate mux (`Open` → `Live`), ftyp/moov/moof/mdat
- [x] Demux: fMP4 + unfragmented `stbl` (mdat-before-moov)
- [x] ClearKey via `iso-cenc` (`tenc`/`senc`)
- [x] Conformance + FATE `oracle_compare`
### 2 — Hardening
- [x] Multi-elst packet expansion (`edts`/`elst`, FATE `mov-3elist` → 74 packets)
- [x] Discard / negative first-PTS (`mov_neg_first_pts_discard`: signed PTS + `is_discard`)
- [x] VP9 (`vp09`/`vpcC`) sample entry — [`adr/0002`](../adr/0002-vp9-sample-entry.md)
- [x] HEVC (`hvc1`/`hvcC`) + AV1 (`av01`/`av1C`) sample entries, honest `ftyp`
compatible brands — [`adr/0003`](../adr/0003-hevc-av1-sample-entry.md)
- [x] HEVC Annex-B → length-prefixed conversion and real `hvcC` construction, with an
ffprobe end-to-end oracle. Until 2026-09-18 an HEVC MP4 written here decoded
zero frames — [`adr/0006`](../adr/0006-hevc-in-mp4.md)
- [x] Mux sample durations derived from `dts` deltas (no silent zero-duration
trun) — [`adr/0004`](../adr/0004-mux-duration-dts-delta.md)
- [x] Opus (`Opus`/`dOps`) sample entry — [`adr/0005`](../adr/0005-opus-sample-entry.md).
`Codec::Opus` previously fell into AAC's `mp4a`/`esds` branch and shipped an `esds`
declaring MPEG-4 AAC over Opus packets: muxed clean, failed on playback.
- [x] Opt-in mux payload placements (`Muxer::with_placements` / `poll_placements`): where
each sample's payload landed in the output — [`adr/0007`](../adr/0007-mux-payload-placements.md)
— 2026-09-25. First caller: qarec's disk-backed replay ring.
- [ ] More codecs / sample entries as needed (`hev1` variant, `dvhe`/Dolby Vision, …)