Use mkvpropedit or ffmpeg mapping to set language tags:

mkvmerge -o out.mkv --language 0:eng midv912_engsub.srt midv912.mkv

Or with ffmpeg when adding subtitle stream:

ffmpeg -i midv912.mkv -i midv912_engsub.srt -map 0 -map 1 -c copy -metadata:s:s:0 language=eng midv912_with_langtag.mkv

The phrase "Convert015856 min" suggests a duration conversion or file transformation task. Let’s explore both:

Solution: Cut the subtitles first. Use ffmpeg to trim the .srt file:

ffmpeg -i subtitles.srt -ss 01:58:56 -t 60 trimmed_subtitles.srt

Search for MIDV-912 English subtitles .srt on dedicated subtitle repositories such as:

Ensure the subtitle file’s runtime matches your video’s framerate (usually 23.976 fps or 29.97 fps).