STT-Assistant/docs/OUTPUT.md

Output & Data

Transcripts reach you three ways: human-readable stdout, machine-readable JSONL, and optional WAV clips.

Stdout (human-readable):

[14:23:45] (es) Hola, cómo estás?  [rms=0.041 end_of_turn]
[14:23:52] (en) What time is it?  [rms=0.038 end_of_turn]
[14:24:10] (es) Gracias por tu ayuda.  [rms=0.052 pause]

JSONL (one line per utterance; only written when jsonl = true):

{"ts": "2025-09-20T14:23:45.123456", "lang": "es", "lang_prob": 0.95, "duration_s": 2.5, "rms": 0.04123, "end_reason": "end_of_turn", "text": "Hola, cómo estás?", "transcribe_s": 0.42}
{"ts": "2025-09-20T14:23:52.654321", "lang": "en", "lang_prob": 0.98, "duration_s": 1.8, "rms": 0.03811, "end_reason": "pause", "text": "What time is it?", "transcribe_s": 0.31}

duration_s is the length of the utterance audio; transcribe_s is the wall-clock time the worker spent transcribing it (inference latency), rounded to milliseconds. Their ratio is the real-time factor. The field is omitted if the timing was not measured (e.g. emit() called directly without transcribe_s).

end_reason is one of end_of_turn (full silence_ms elapsed), pause (chunked at chunk_pause_ms because it passed soft_max_s), hard_cap (max_utterance_s reached), or flush (shutdown mid-utterance).

Audio files — when save_audio = true, each transcribed utterance is also written as a 16 kHz mono WAV under audio_dir/YYYY-MM-DD/, and the record gains an "audio" field with its path:

{..., "end_reason": "pause", "text": "Hola", "audio": "audio/2025-09-20/142345-123-pause.wav"}

Saving is best-effort: if a write fails (e.g. disk full), the transcript is still emitted and a warning is logged.

⚠️ Disk space — saved audio is never rotated or cleaned up automatically. At 16 kHz mono 16-bit it costs 32 KB/s, i.e. ~1.9 MB/min, ~115 MB/hour, ~2.8 GB/day of continuous speech. Silence is not written, so real usage is lower — but an always-on daemon in a talkative room still accumulates quickly. Point audio_dir at a volume with headroom and prune it yourself (e.g. a cron job removing files older than N days), and leave save_audio = false unless you actually need the clips for auditing.