Prepare a clean subtitle file
SRT and VTT are straightforward choices for ordinary text. ASS and SSA can carry richer positioning and styling. Before import, inspect the text encoding, timestamps, line breaks, and spelling. Keep the original subtitle file and a separately named corrected copy.
Add or replace the subtitle
Preview the existing video
Play a section with dialogue and identify any existing subtitle track and its timing.
Choose the subtitle action
Keep the original track, remove it, or replace it by selecting an SRT, VTT, ASS, or SSA file.
Correct a fixed timing offset
If every line is early or late by the same amount, shift the subtitle start. An error that grows over time usually requires correcting the subtitle time base instead.
Select the export mode
Use fast remuxing when only adding a compatible subtitle. Choose compatible transcoding when also trimming, changing speed, rotating, cropping, or adjusting audio.
Review three points
Check dialogue near the beginning, middle, and end in the actual target player.
Understand the export choice
| Requirement | Suggested mode | Reason |
|---|---|---|
| Add a compatible subtitle only | Fast remux | Usually avoids video re-encoding |
| Combine subtitles with visual or audio edits | Compatible transcode | Applies all editor settings |
| Target device has limited subtitle support | Compatible transcode | Produces a more uniform playback result |
Diagnose subtitle drift
- Compare the first spoken line with its subtitle.
- Check again near the end of the video.
- Use a start offset only when the difference remains constant.
- If the error grows, check frame rate and subtitle timing.
- Remember to shift subtitles after removing an intro.
Frequently asked questions
Which subtitle formats are supported?
webcool supports SRT, VTT, ASS, and SSA. Styling support can still differ between players.
Will adding subtitles reduce video quality?
Fast remuxing normally avoids video re-encoding. Compatible transcoding re-encodes the output, so quality and size depend on the selected settings.
Why does an ASS subtitle look different?
The server may be missing a font, or the player may not support every effect. Install required fonts or use a compatible transcode.