The fastest way to handle an EngSub translation file is to avoid touching the underlying video codec whenever possible. If your container target permits, separate the text track ( .srt , .vtt , or .ass ) from the raw video stream using an open-source framework like FFmpeg.
Match Source (Peak Framerate / Variable Framerate should be turned off to keep audio synced perfectly across the 2-hour duration). nsfs324engsub convert020052 min best
