# Choose the right audio track before generating subtitles A video can contain main dialogue, dubs, commentary and descriptive audio in separate tracks. Inspect and audition the track you want before generating subtitles in 110+ target languages. Changing the target language does not change which track is transcribed. ## A video container can hold more than one soundtrack The filename extension does not tell you how many audio tracks a file contains. A movie may include its original dialogue and several dubs. A lecture capture might have a room microphone and a direct speaker feed. A bonus commentary can sound like normal conversation while describing the film rather than reproducing its dialogue. Selecting the right track is therefore part of preparing the subtitle, not a minor playback preference. SubLunio inspects local media and shows the available audio choices. Track metadata may include a language label, codec or title, but those labels can be missing or wrong. Use them as clues. If the label says English but the sample is clearly another language, trust what you hear and verify the selection before starting a paid full-length task. ## Listen to a representative sample Use the local track audition to hear a short section. If the opening contains only music, silence or a distributor logo, a brief sample may not identify the track; check the file in your usual player at a point with recognizable dialogue. Listen for whether the voices match the on-screen speakers and whether extra commentary talks over the scene. Headphones can make a quiet channel easier to judge, but turning up playback volume does not repair clipped or missing speech. When two tracks contain the same conversation, prefer the clearer direct recording. Keep a note of the selected track for a series or batch, because the ordering of tracks can differ between files even if their names follow the same pattern. ## Keep source language and subtitle language separate The source language describes the speech in the selected track. The target language is the text you want to read. For a Japanese soundtrack with English subtitles, choose that soundtrack and English as the target; Auto can be used for source detection, or you can explicitly choose Japanese when that is the primary spoken language. SubLunio’s target menu covers 110+ subtitle languages. Speech recognition has its own supported language set, so the two menus serve different purposes. A film that switches languages may still need careful review around those transitions. Choosing a target language cannot make an unsupported or unintelligible source suddenly clear, and choosing a different source label does not switch to another audio stream. ## Distinguish a codec problem from a missing track A container such as MP4 or MKV is a wrapper around streams. The audio inside may use AAC, AC-3, DTS, PCM or another codec. Your browser may display the picture but be unable to play a particular soundtrack directly. SubLunio’s local extraction path can produce an MP3 for subtitle work when the decoder supports that stream; the workspace reports an extraction problem when it cannot. Do not repeatedly upload a silent or wrong output hoping that speech recognition will choose a different track. Recheck the source file and track first. Encrypted or protected media requires an authorized accessible source; the subtitle workflow does not remove protection. A damaged recording may need recovery in a media tool before a reliable timeline can be produced. ## Review sound and subtitles on the same timeline During preview, native video playback is used where the selected media combination plays smoothly. If the browser cannot play it, displays only a still frame or keeps stalling, the preview switches to subtitle text with the original video timestamps. You can review the wording and switch between translated, original and bilingual text. This does not change subtitle generation, payment or download. The original video remains on your device; no public movie copy is created. Watch a recognizable mouth movement or scene event while listening to a line. If the wrong voice or commentary appears, return to the track choice. If timing is consistently displaced, confirm the exact source version and any edit at the beginning. Preview quality is an opportunity to catch these preparation problems before you continue with the remaining duration. ## Carry the selection carefully into batch work The desktop queue is useful when several files need the same output languages, but each file still has its own stream layout. Inspect unfamiliar files before treating track index one as a universal default. A dub can be the first track in one episode and the second in the next. Metadata that looks consistent should be checked against a few representative recordings. For handover, record the source edition, chosen spoken language and target subtitle language. Keep the original file available while processing, since moving or replacing it can interrupt local extraction. When a task reports no speech, first rule out an empty track or an opening-only sample; generating more translations of the same empty audio will not produce useful dialogue. ## Does selecting English subtitles select an English dub? No. The target language controls translated text. Choose the audio track separately. ## Can the first audio track be commentary? Yes. Stream order and metadata vary by file, so audition or inspect the selected track. ## Why can I see the picture but hear no original sound? The browser may support the video codec but not the audio codec. Subtitles can still be generated from the locally extracted audio; the page switches to a subtitle text preview. ## Should I always set a source language instead of Auto? Auto is a useful starting point. Choose the known source language when detection is wrong or the main spoken language is clear. ## Keep exploring - [Fix common subtitle problems](https://sublunio.com/guides/subtitle-troubleshooting) - [Create subtitles from MKV](https://sublunio.com/mkv-subtitle-generator) - [Translate the selected speech](https://sublunio.com/subtitle-translator) Source page: https://sublunio.com/guides/video-audio-tracks Last updated: 2026-09-24