ffmpeg is a powerful cross-platform solution to record, convert and stream audio and video.
You can also use
ffmpeg to trim videos without reenconding in seconds:
ffmpeg -i presentation-video-input.mp4 -c copy -ss 0:10:55 -to 0:36:18 presentation-video-output.mp4
-i url: input file.
-c copy: indicates that the stream is not to be re-encoded.
-ss position: start video from this position.
-to position: end video at this position.