# Planned Parquet schema

Schema version: `bagpiper-self-contained-parquet-v1`.

Every row contains one complete natural-language-guided synthesis example and
its encoded audio. Parquet shards target approximately 256 MiB and never split
an example.

| Field | Type | Description |
|---|---|---|
| `row_id` | string | Globally unique `source_subset:example_id` release key |
| `example_id` | string | Original source identifier |
| `partition` | string | One of the six public application names |
| `source_subset` | string | Internal source corpus retained for provenance |
| `split` | string | Release split, initially `train` |
| `direction` | string | `text_to_audio` |
| `messages` | list of structs | Ordered `{role, modality, content, audio_index}` conversation |
| `audio` | struct | `{path, bytes}` containing the complete encoded target audio |
| `audio_sha256` | string | SHA-256 of encoded audio bytes |
| `audio_bytes` | int64 | Encoded byte length |
| `audio_format` | string | Source container/codec suffix |
| `sample_rate` | int32 | Decoded sample rate |
| `channels` | int16 | Channel count |
| `num_frames` | int64 | Decoded frame count |
| `duration_seconds` | float64 | Decoded duration |
| `metadata_json` | string | Sanitized source annotations; no paths or usernames |
| `source_revision` | string | Pinned raw Hugging Face source revision |
| `schema_version` | string | `bagpiper-self-contained-parquet-v1` |

Text is preserved verbatim. The audio-message content is replaced with a
portable display filename and points to the embedded `audio` value by
`audio_index`; no private source path is retained.

All rows use exactly this message pattern and contain no system role:
`user:text → assistant:text → assistant:audio`. Every row contains exactly one
audio object. Intended reuse of valid audio across rows is preserved.