How to make a video for submission

On macOS, we need to follow these steps to make a video for paper submission:

use keynote to make slides and animations
keynote has a record slide play function, it also can show notes
after exporting the video, drag it to keynote again to change aspect ratio to widescreen
use HandBrake to compress the video to within 20MB, frame rate > 20
use ffmpeg -i video_name to check frame rate

For Ubuntu, we can use RecordMyDesktop to record screen. Its output format is ogv, which can be coverted to avi via ffmpeg as in here

ffmpeg -i input.ogv output.avi

we can also convert .gif to video on ubuntu by

ffmpeg -i sem_track_images.gif -movflags faststart -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" video.mp4