You can use ffmpeg for this, using "copy" for audio and video, but setting "-ss <hh:mm:ss.0>" for the start time and "-t <seconds>" for the length of your cut b

You can use ffmpeg for this, using "copy" for audio and video, but setting "-ss <hh:mm:ss.0>" for the start time and "-t <seconds>" for the length of your cut beginning from the start timestamp given with -ss.