fix(transcription): a recording with no audio is a verdict, not a failed job - #638

Summary

A screen capture recorded with no system audio and no microphone was reported as a failed transcription job, NoAudioTrackError and all.

The root cause is one classifier. classifyTranscriptionError still only knew the phrasings the renderer's web-demuxer produces ("no audio track", "zero audio frames"). Native ffmpeg extraction landed with its own — NoAudioTrackError says "No decodable audio in …" — so the verdict fell through to the generic "error" kind, and every consequence of that kind followed: a red failed job in the Transcription inspector, a toast carrying raw ffmpeg stderr, and no persisted verdict, so the auto pass re-extracted the same silent file on every project open.

Matching on the message rather than on the class is not a shortcut: ipcRenderer.invoke rebuilds a plain Error and drops both the prototype and the name, so the message is what crosses. The new phrasing joins the other two, and the architecture doc now says why a new decoder has to register itself there.

Everything downstream already treated "no-audio" as an expected outcome rather than an incident — it was simply never reached. What was still styled as an incident once it is:

• the media-card dot and the media-stage pill go amber, the colour "no speech detected" already uses, rather than danger red. Behind isSilentFailure, because four call sites were painting on status === "failed" alone;
• the dot's tooltip drops the raw engine message, and the stage says "this media has no audio track" instead of "generation failed";
• a run the user asked for by hand gets an informational toast instead of a red one. The background pass stays silent, as before.

Related issue

Fixes #628

Type of change

• Bug fix
• Feature
• Enhancement
• Documentation
• Refactor / maintenance
• Performance
• Security

Release impact

• Patch
• Minor
• Major / breaking change
• No release note needed

Desktop impact

• Windows
• macOS
• Linux
• Installer / packaging
• Not platform-specific

Screenshots / video

None. The change swaps copy and two colour tokens on states that already existed; the states themselves are covered by the unit tests below.

Testing

npx vitest run src/components/ai-edition src/lib/ai-edition electron/stt

108 files, 1356 tests pass. biome check and tsc --noEmit are clean.

Three tests added:

• the native extractor's message, wrapped the way ipcRenderer.invoke wraps it, classifies as no-audio;
• isSilentFailure separates the media verdicts from an engine failure, and does not fire on a view that carries a failure alongside a usable transcript;
• a hand-asked run on a silent media toasts informationally, and the background pass that found the silence first said nothing.

Not covered by unit tests, and worth a look on the reproduction from the issue: the Transcription inspector's own empty state, which already keyed off the gate reason and only ever needed the classification to be right.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes

  • Improved handling of recordings with no audio track.
  • Manual transcription attempts now show an informational “no audio track” notification instead of an error.
  • Automatic background transcription remains unobtrusive for silent recordings.
  • Silent recordings now use neutral status styling and display a more relevant empty-transcript message.
  • Genuine transcription and media failures continue to display their appropriate error states.

• Documentation

  • Clarified how silent recording results are identified and retained.