This usually happens if the input file bitrate is too high for the JUR153 processor. Try downscaling to 1080p before transferring.
For soft subtitles (separate track):
HandBrake is a premier choice for this task. It offers a fully portable version that allows you to convert files and burn in subtitles on the go. jur153engsub convert020006 min portable
If you need precise control over how the English subtitle is embedded or styled, StaxRip provides the advanced options that HandBrake might simplify. This usually happens if the input file bitrate
The subtitles are permanently merged into the video frames. They cannot be turned off or changed. jur153engsub convert020006 min portable