9. Feb 2021 |

Notes for myself: Videos of lectures – how I watch

On fridays I have up to 9 hours of lecture videos to watch. It is split into 3 x 3h videos. Each “video” on Echo360 is actually 3 files: audio file, video of computer screen (presentation) and view from camera to blackboard.

I download screen and audio files from Echo. In order to get video with audio as one file I join them with:

ffmpeg -i video.m4s -i audio.m4s -c:v copy -c:a aac output.mp4

As 3 videos per every friday over 16 weeks would make 48 videos I try to join videos of every week by using:

ffmpeg -f concat -safe 0 -i list.txt -c copy output.mp4

So I have 16 videos on my Youtube for these subjects. List.txt is list of files structured like:

file '00-video.mp4'
file '01-video.mp4'

In order to skim through the video first I use opportunity to speed up the video. I mark down important parts and the work through the material.


ffmpeg -ss 00:01:00 -i input.mp4 -to 00:02:00 -c copy output.mp4

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