# Transcribe

Requires Bash, FFmpeg, curl, jq, and standard coreutils; `--srt` also requires
Python 3 and the accompanying `subtitles.py` file.

```sh
./transcribe recording.m4a
./transcribe video.mp4 > transcript.txt
./transcribe --srt video.mp4 > subtitles.srt
```

Accepts m4a, mp4, aac, flac, opus, mp3, ogg, wav, and other formats your
FFmpeg supports. Uses the first audio track, converts it to mono 16 kHz MP3
at 64 kbps (requires FFmpeg's libmp3lame encoder),
and sends it to OpenRouter's `microsoft/mai-transcribe-2` model. Temporary
files are removed on exit. The transcript goes to stdout; errors to stderr.

`--srt` requests word timestamps using OpenRouter's `verbose_json` response.
Words are grouped into cues of at most two lines (42 characters per line,
except an unusually long unbroken word) and six seconds. Cues also break at
sentence endings, pauses of at least 0.7 seconds, and speaker changes when
speaker labels are available. Timing comes from the words, rounded to
milliseconds. Subtitle output goes to stdout; missing or invalid word timestamps
produce an error. Without `--srt`, output remains plain text.

One file per invocation; the whole recording is sent in one request, so
the service's audio length and request size limits apply.

[OpenRouter model and API reference](https://openrouter.ai/microsoft/mai-transcribe-2)