# src/rttm
## Purpose
RTTM (Rich Transcription Time Marked) file parsing, grouping, and writing.
## Surfaces
- `RttmSegment`
- `RttmError`
- `parse_rttm`, `parse_rttm_file`
- `group_by_file`
- `to_speaker_turns`
- `write_rttm`
## Dependencies
- `types` — SpeakerId, SpeakerTurn, TimeRange
## Invariants
- write_rttm ∘ parse_rttm preserves segments (within formatting).
## Verification
```bash
cargo test --lib rttm
```
## Notes
- Standard RTTM format used by NIST and pyannote.