Start with the right source
Keep an untouched copy of the subtitle file before opening a working version. If a production workflow already has an authoritative caption master, treat this workbench as an interchange editor rather than an automatic replacement. Choose the source format explicitly when detection is ambiguous, and read any conversion losses before making edits.
The editor accepts a bounded number of UTF-8 cues. A text file that displays incorrectly may use a different encoding. Convert its encoding in a trusted application before importing rather than assuming that replacement characters represent the original dialogue. The original downloadable text is the text that was actually decoded for this session.
Use playback to judge each boundary
Choose an optional local video or audio file. Browser codec support controls whether it can play, so a file that works in a desktop editor may need a compatible export. The media is referenced through a temporary local object URL and is not sent to a transcription service. Press Play and compare the visible caption with the spoken words.
Select a cue and seek to its start when checking a difficult transition. The playhead controls copy the current media time into the start or end field; Apply cue edit commits the values. Keep a positive duration and leave time for the viewer to read. A fast caption may need shorter wording, a longer duration or a sensible split rather than a uniform shift.
Review changes before delivery
Split at midpoint makes two consecutive cues and divides the words approximately in half. It does not understand linguistic phrasing. Edit the new boundaries and wording to match the dialogue. Merge with next combines the selected cue with the next source-list cue; inspect the result when the original list is not chronological.
Undo restores up to 25 committed edits within this tab. Download the current edit audit to retain the revised cue list and check results. Export the destination format and play it in the actual receiving application before distributing it. A valid timed-text file can still look different because player fonts, wrapping and caption preferences differ.