Updated
Find out which problem you have
- Note how far off a line near the start is.
- Jump to near the end and check a line there.
- If both are off by the same amount, you have a fixed offset. If the end is off by much more, the timing drifts.
Fix a fixed offset
A fixed offset usually comes from a different cut of the video, such as an extra intro or a missing studio logo. Every cue needs to move by the same amount.
Measure the gap on one line, then shift all cues earlier or later by that many seconds and milliseconds. If only part of the video is off, for example after an ad break, shift only the cues from that time onward.
Fix drift from a different frame rate
Drift happens when the subtitles were timed for a version of the video with a different frame rate. The common case is film at 23.976 frames per second against a European release at 25. The 25 fps version runs about 4 percent faster, so a feature film ends several minutes earlier.
Shifting cannot fix this, because the error grows over time. The timings have to be scaled instead. The time shifter has presets for 23.976 to 25 and 25 to 23.976. After scaling, check the first line again and add a small shift if needed.
Things to check afterwards
- Cues that would start before zero are set to zero, so check the first lines if you shifted earlier.
- The output keeps the format you put in. SRT stays SRT and VTT stays VTT.
- If your player needs the other format, convert the fixed file.
