Vietnamese lecture captions

The caption menu now matches the language learners read. Actual beta screenshots show the correction on the existing test video.

SP-679 · Verified 10 Nov 2026 · Asia/Saigon

Beta verification passed

Deployment: PR #692 is merged and deployed to beta.
Result: Tiếng Việt selected. Vietnamese subtitles visible. Playback verified.
Scope: One existing beta test video repaired. The video was not regenerated.
Evidence: These are real beta UI captures from the signed-in Chrome session, using test course content.
Ticket: SP-679: Lecture video generation from PowerPoint and transcript

What was wrong

This course was set to English, but its generated lecture used Vietnamese narration. The subtitles contained Vietnamese text. The backend copied the course language into the transcript, so Bunny displayed the track as English.

What changed

1 · Source

Vietnamese narration

The subtitle language follows the lecture narration.

2 · Stored transcript

Vietnamese retained

A retry corrects the language even when the text is unchanged.

3 · Player

Tiếng Việt

The caption track uses Vietnamese language and label.

Proof from the beta UI

Actual beta lesson with Vietnamese subtitles and Tiếng Việt selected in the caption menu. — After repair, 10 Nov 2026: the beta player shows Tiếng Việt with language code VI. The subtitle text is Vietnamese. Click to open full size.

Compare with the original label

Actual beta lesson before repair, with Vietnamese subtitle text but English selected. — Before repair, 9 Nov 2026: the same beta video had Vietnamese subtitle text under an English caption track. Click to open full size.

How to check it yourself

Open the beta test lesson with an account that can access this draft course.
Play the video, open Settings, and select Captions.
Choose Tiếng Việt. Read the Vietnamese subtitle text while the video plays.

Verification results

Check	Observed result
Stored transcript	Corrected from English US to Vietnamese.
Bunny caption track	Exactly one track: Tiếng Việt, Vietnamese. Incorrect English track removed after backing up and comparing its text.
Subtitle content	All caption text and the saved subtitle hash stayed unchanged.
Playback	Playback advanced from 3 seconds to 4.267 seconds, then paused successfully. Video duration: 50.539 seconds.
TDD regression	Eight cases failed with the wrong language before the fix and passed afterward. Real database and services; external Bunny HTTP response faked.
Automated checks	2,986 local unit tests passed before push. PR backend, database, migration and code-review checks passed.

Known limits

This check covered the caption-language correction and one repaired beta video. It did not create a new generation job or retest every lecture-generation acceptance criterion.
Other older caption tracks are not automatically repaired by deployment. Check them before using them as proof.
Production verification was not performed. Jira closure was requested by the user after beta verification.
The local repository-wide type check reported 1,759 errors, with none on the changed lines. The initial full database run had one database-configuration failure that passed on a serial rerun.

Rollout record

Complete: regression test, fix, merge and beta deployment.
Complete: existing beta test-video caption repair and real UI verification.
Complete: before-and-after proof captured from beta.
Production release and other old-video repairs are outside this verification.