Before changing every subtitle, identify the kind of timing problem. A constant delay, a gradual drift and a cut in the video need different corrections.
Measure the offset
Find a clearly spoken word near the beginning. Compare its audio time with the cue's start. If the caption begins two seconds late, an offset of minus two seconds moves it earlier. Recheck near the end before applying the shift globally.
Use a global shift only when it fits
The SRT editor changes all cue starts by the same offset and preserves their durations. It clamps negative start times to zero. It cannot fix an increasing drift or compensate for multiple edits in the source recording.
Clean a reading copy
Use the subtitle formatter when you need a readable transcript without markup or cue numbering. Keep a separate SRT or VTT source if the final deliverable is subtitles. Stripping timestamps removes information you will need for playback alignment.
Preview important boundaries
Check the first spoken line, scene transitions, long pauses and the closing sentence. If the content is educational, verify names, equations and commands as well as timing. Download the result and preserve the original for comparison.