After recording a video, you can use the following options:
You can add subtitles (transcriptions) to video steps. Here you can see an example: https://stepik.org/lesson/7560/step/1.
Adding can be done in the video step editing mode for those videos that were uploaded via a link or directly to Stepik.
Subtitles should be added in text form (WebVTT format, see https://en.wikipedia.org/wiki/WebVTT).
Working with ffmpeg
To use ffmpeg, please download and install it from https://ffmpeg.org/download.html. The program is launched via command prompt and can be used for changing the format and video compressing (see https://ffmpeg.org/ffmpeg.html#Description).
To merge several videos, use terminal to launch the following script from https://github.com/mehanig/common/blob/master/video_concater_and_compressor.sh
Compressing large videos
Use terminal to launch the following command ffmpeg -i INITIAL_VIDEO.mp4 -codec:a copy -vcodec libx264 -preset slow -crf 25 COMPRESSED_VIDEO.mp4