Speech‑to‑text and text‑to‑speech on Yandex SpeechKit from one Python stdlib file

Описание и применение

Минимальный сервис на одном VPS, использующий только стандартную библиотеку Python и ffmpeg, который транскрибирует и синтезирует аудио через Yandex SpeechKit, контролирует расходы и хранит файлы не дольше суток.

Задача

Need to transcribe long meeting recordings and synthesize voice from text without paying for a separate SaaS, keeping costs predictable and data short‑lived.

Результат

A minimal, self‑contained service that transcribes and synthesizes audio on a single VPS, with cost control, data retention policies, and no external SDKs.

Рабочий процесс

• Upload MP3 via multipart to HTTP server
• Store job in SQLite queue
• Worker threads convert audio with ffmpeg
• Send file to Yandex SpeechKit (async for long files)
• Poll operation status until done
• Parse JSON‑lines result, merge words and punctuation
• Generate SRT subtitles and JSON timing file
• For TTS, split text into 240‑char chunks, synthesize with utteranceSynthesis
• Concatenate MP3 frames
• Return text, SRT, and MP3 to client
• Cleanup files after 24h
• Enforce cost ceilings and per‑user limits

Доказательства

The problem was mundane. On one side, meeting recordings: an mp3 of an hour or an hour and a half, out of which I needed text and subtitles.

Источник

What came out is a single Python 3.12 file of roughly 2,200 lines: http.server with threads, sqlite3 as the job queue, urllib for everything external, ffmpeg for conversion.

Источник

The queue is hand‑rolled too, and it is surprisingly boring: a jobs table in SQLite, two worker threads, the statuses queued → processing → done|error, and a stage field holding a human‑readable string like "converting" or "recognizing".

Источник

The result of getRecognition is not JSON but a stream of JSON lines, one object per line — that is the first non‑obvious thing.

Источник

Synthesis in v3 is called through the utteranceSynthesis method, and it has a limit on text length that the documentation says approximately nothing about.

Источник