Subtitle Processing v2.4

Bazarr+ v2.4.0 (Prism) adds three subtitle processing features: combined bilingual or trilingual subtitles built from files already on disk, source scoring and direct translation for embedded tracks, and multi-engine synchronization with side-by-side output comparison. This guide covers all three.

Combined subtitles

Combined output takes subtitles you already have on disk and composes them into a single bilingual or trilingual subtitle, written as SRT or ASS. You pick two or three languages, and Bazarr+ aligns their cues into one file.

A film playing in Jellyfin with a combined bilingual subtitle: Hungarian on the top line and English on the bottom line, composed by Bazarr+ as a single ASS file
This is pure composition, not translation. Combined output only stacks subtitles that already exist on disk. It never triggers a translation, never calls a provider, and never extracts an embedded track. If not all of the chosen source languages are present, Bazarr+ skips the combine silently and leaves your existing subtitles untouched.

When more than one variant of a language is on disk, Bazarr+ resolves the source by priority: plain first, then HI, then forced. ASS output supports cue positioning so you can place each language at the bottom, top, or middle of the frame. SRT output stacks the lines in a single block.

Per language profile

Set up combined output once per language profile so it runs automatically as part of normal processing.

  1. Open Settings > Languages and edit a language profile.
  2. In the CombineRuleEditor, toggle combined output on.
  3. Pick 2 or 3 languages to combine.
  4. Choose the output format: SRT or ASS.
  5. Save the profile.

After this, whenever Bazarr+ finishes processing subtitles for an item on that profile and all chosen source languages are present on disk, it builds the combined file automatically. If a source language is missing, the combine is skipped and no error is raised.

On demand

You can also build a combined output now, without waiting for the next processing pass.

  • On a movie, episode, or series detail page, use the Combine Subtitles toolbox button.
  • On the Movies or Series list pages, use the mass-combine action to build combined output across the selected items.

The same source rules apply: only on-disk subtitles are used, source priority is plain > HI > forced, and items that do not have all source languages are skipped.

Managing combined output

Combined subtitles are indexed alongside other generated outputs and marked with a CombinedSubtitleBadge in the subtitle table. Each combined row has an overflow menu:

  • Rebuild: recompose the combined file from the current on-disk sources.
  • View: open the combined subtitle.
  • Edit: open the combined subtitle in the subtitle editor. An SRT combined opens as one stacked cue per timestamp; an ASS combined opens as its separate positioned cues (one per language) without false overlap warnings.
  • Delete: remove the combined file.

A combined output is kept as a single file: rebuilding in a different format removes the stale sibling left in the previous format.

API endpoints

The on-demand and mass-combine actions call these endpoints. The series endpoint is the batch form that combines across the show's episodes.

HTTP 
POST /api/movies/<id>/subtitles/combine
POST /api/episodes/<id>/subtitles/combine
POST /api/series/<id>/subtitles/combine

Embedded subtitle scoring and translate-from-embedded

Embedded subtitles are tracks stored inside the media container rather than as separate files. Bazarr+ now treats those in-container tracks as a real subtitle source.

Source scoring in history

An embedded track is recorded in history as a source-quality result at a 100% score. In the subtitle table, the embedded track shows that 100% score so you can see at a glance that the item already carries an in-container subtitle for that language.

Translate from an embedded track

You can translate directly from an embedded text track without first downloading a separate subtitle. The embedded row exposes a translate-only action in its menu.

  1. In the subtitle table, find the embedded track you want to translate from.
  2. Open its action menu and choose the translate-only action.
  3. Bazarr+ extracts the text stream with ffmpeg to {config_dir}/extracted_subs/.
  4. It then runs your configured translator on the extracted text and writes the translated subtitle.
Text-based tracks only. Translate-from-embedded works on text subtitle codecs. Bitmap codecs such as PGS and VobSub cannot be translated this way and are rejected with a clear error, because there is no text to feed the translator. ffmpeg must be available for the extraction step.

Translation uses whatever engine you have set up in Bazarr+. See AI Subtitle Translation for configuring a translator. Sync outputs and combined outputs are intentionally excluded from the list of sources you can translate from, so you translate from real source tracks rather than from generated files.

Multi-engine synchronization

Synchronization shifts subtitle timing to match the audio. Bazarr+ now lets you choose which sync engine to run and compare the result before you keep it.

You can start a sync in two places:

  • From the subtitle editor, on a single subtitle.
  • From the mass-sync form, across multiple items at once.

In either place you pick the engine to run. When the editor sync finishes, the SyncOutputCompareModal shows the produced output next to the original side by side, so you can confirm the timing improved before committing to it.

Editor sync now fails explicitly. If a sync run produces no output, the editor reports the failure instead of silently leaving the subtitle unchanged. You see that the engine did not produce a result rather than assuming it succeeded.

Next steps