FFmpeg

FFmpeg is the assembler of audio and video.

As a result, Ciro Santilli who likes "lower level stuff", has had many many hours if image manipulation fun with this software, see e.g.:

As older Ciro grows, the more he notices that FFmpeg can do basically any lower level audio video task. It is just an amazing piece of software, the immediate go-to for any low level operation.

FFmpeg was created by Fabrice Bellard, which Ciro deeply respects.

Resize a video: superuser.com/questions/624563/how-to-resize-a-video-to-make-it-smaller-with-ffmpeg: Unlike every other convention under the sun, the height in scale is the first number.