Once you've selected your converter, chosen your output format, ensured subtitle support, and set your quality settings, you can proceed with the conversion.
Using FFmpeg (legal on your own file):
ffmpeg -i trimmed.mkv -c:v libx264 -b:v 1500k -pass 2 -preset slow -c:a aac -b:a 128k -movflags +faststart output_1500k.mp4

