Transcription has to run on the user's own hardware, and the only speech-to-text
path so far was the OpenAI voice key. Self-hosted whisper servers (whisper.cpp,
faster-whisper based servers, vLLM) all speak the OpenAI transcriptions
protocol, so one provider covers them.
- createOpenAiCompatibleTranscriptionProvider posts a multipart upload to
{base}/audio/transcriptions asking for timed segments, falls back to plain
JSON for servers that reject verbose_json, reads text/plain bodies, and
reports failures in words. It reuses the address-checked fetch and URL
guards of the other OpenAI-compatible adapters, caps uploads at 25 MiB and
responses at 8 MiB, and builds the multipart body by hand because the
undici fetch behind the address checks does not serialize the global
FormData class.
- An in-process server emulator (OpenAI/whisper.cpp, plain-JSON-only and
text-only flavours) and an in-process provider back an offline
conformance suite, plus one loopback test through the real fetch.
- toSrt/toVtt in core turn segments into SubRip and WebVTT, wrapping long
segments into cues of at most two 42-character lines that share the
segment's time, and escaping WebVTT cue text.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MRtGG9ARfqqhma3t85Ro2u
3f85cb0420