The term convert in your keyword hints at converting subtitle formats or embedding them into a video container. Common conversions:

This denotes the exact runtime of the file— 1 hour, 58 minutes, and 38 seconds . This is standard for feature-length Japanese productions, which typically run between 100 and 150 minutes. Summary of the Content

The 01:58:38 (1h 58m 38s) mark is often used to verify subtitle alignment during dialogue-heavy scenes near the end of a 2-hour video. If the subs are off by even 0.5 seconds, the encoder adds a delay: