Add selectable subtitles to a DVD

Start with the film the audience will see

Suppose a local theatre has permission to distribute its filmed production on DVD. The main feature has English captions and French subtitles. A short bonus interview has English captions only. Before anyone builds a menu, list the choices that should work for each title. Agree on what pressing Play from the main menu should do on a fresh start. Some audiences need captions on immediately. Write that decision down so the person testing the disc knows what to expect.

Play the exact feature master with subtitle display disabled. Watch a passage with dialogue. If English words are already part of the picture, the disc’s Off choice cannot remove them. Obtain the clean master if the brief calls for switchable English. Check the bonus separately. A clean feature tells you nothing about how the interview was exported.

Give the author one SRT per choice

Use the cut identifier, title and language in each filename. For this production you might send StageDoor-feature-v6-en-SDH.srt, StageDoor-feature-v6-fr.srt and StageDoor-interview-v2-en-SDH.srt. SDH identifies a file prepared for deaf and hard-of-hearing viewers. Use that label only when the captions include the relevant sounds and speaker information. The author also needs the matching picture for each title and the wording the theatre approved for its menu.

Open each SRT with its matching picture in Polyglot. Check a distinctive passage near the beginning and another late in the title. For the interview, start from its own first frame. A sidecar timed against the whole evening’s recording may open with minutes of silence once the interview becomes a separate DVD title. Keep the approved files and make a new export for any correction. Send the files separately so the viewer can select one language at a time.

Pick a cue that identifies each stream

A shared name or a number makes a poor test line. If both languages say “Anna” at the same time, you can select the wrong stream and still think the button worked. Pick a passage where the two versions look different. Include a sound-only passage if the disc distinguishes a dialogue translation from captions.

Here is an invented check sheet for the theatre’s feature. These are elapsed times from the start of the feature. The second row uses a silent gap in the French subtitle file that the translator approved for this example.

FEATURE v6 · 00:02:14
English SDH
Leave the key on the sill.
Français
Laisse la clé sur le rebord.
Off
No caption

FEATURE v6 · 00:02:20
English SDH   [three knocks]
Français      No cue
Off           No caption

Connect each button to the right stream

The DVD author builds the disc in an authoring tool such as DVDStyler. Add the feature and interview as separate titles, then associate each title with its approved subtitle files. Keep a record of the stream order and set the corresponding language on each subtitle stream. DVD-Video stores the subtitles as pictures. The spumux manual describes how SRT text is rendered into those pictures, including how the author can choose the font, alignment and margins.

In DVDStyler’s menu editor, a button has a visible label and a separate action. Give the feature’s language menu three choices and set each action to select the intended subtitle stream or disable subtitle display. Have the action start the feature or return to a clearly labelled Play button that preserves the choice. Highlighting “Français” on the menu proves only that the button can receive focus. Follow its action into playback.

For example, the DVDStyler scripting guide numbers subtitle streams from zero. Its show-all value for stream 0 is 64, and for stream 1 it is 65. If English occupies stream 0 and French occupies stream 1, the French button needs to select the second stream. If you delete English and add it again, recheck the actual order before copying those assignments to another menu. The numbers identify positions in this title, independent of the words printed on the buttons.

Supply a separate instruction for the bonus. If it starts with English captions by design, its Play button should establish that state even when the viewer has just watched the feature in French. A single menu that advertises French for both titles promises a translation the theatre has never provided.

Preview the authored DVD with the remote

Use DVDStyler’s preview-before-burning option. Open the authored DVD from its menu in a DVD-capable player. Playing the original movie beside its SRT bypasses the menu, the rendered pictures and the button actions you need to inspect. Start at the main menu and use only directional navigation and Select. Confirm that every choice is reachable and that you can see which button has focus.

Choose Français and play the feature through the key-on-the-sill line. Check the accent in “clé” and the last word near the right edge. Return to the language menu, choose English, and check both the spoken line and the three knocks. Now choose Off immediately after English. Test at the spoken line as well as at the knocks. A blank screen during the gap in French could otherwise pass as a working Off button.

Repeat the path that crosses titles. Play the feature in French, go back, start the bonus and check its first caption against the interview file. Finally, restart the disc from the beginning and try the ordinary Play button without opening the language menu. Record the player and its subtitle preferences alongside that result. A player resuming the last session can hide a faulty start action.

Use the failed check to find the repair

If the French button plays English, use the player’s own subtitle selector on the same title. When that selector reaches the correct French line, inspect the menu button’s stream assignment. If the player offers French but shows English there too, check the source file, stream order and language declaration together. Changing the text printed on the button leaves the underlying stream untouched.

If Off leaves words on screen, replay that moment in the clean master first. Words visible there need a different picture master. If the master is clean, test the player’s subtitle control and inspect the disc’s menu action and any forced-display settings for the affected cues. A caption deliberately flagged for forced display can survive an ordinary language change. Agree with the producer about which passages, if any, should do that.

If both languages switch correctly but the accent is missing, open the approved SRT. A correct accent there sends the author back to the text encoding and font used to render the subtitle pictures. If the right-hand edge is clipped only on the television, review the authored margins and the display mode on the intended equipment. Check the rendered line again after rebuilding the disc.

Before duplicating a run, play a proof disc on the intended hardware and repeat the start, language change, Off and bonus checks. Include the image build identifier, player, title, menu path, cue time, expected line and observed line with any fault report. Keep the corrected authoring project and editable SRTs together. They are what the next person will need when the theatre asks to fix one word.

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