Video editing

Video recordings could be useful for people attending a course later, but also are (perhaps more) useful for immediate review and catching up after missing a day in a workshop. For this, they need to be released immediately, within a few hours of the workshop. CodeRefinery can do this.

Primary articles

• Video editor role description: https://coderefinery.github.io/manuals/video-editor/

• ffmpeg-editlist: the primary tool: https://github.com/coderefinery/ffmpeg-editlist

  • Example YAML editlists: https://github.com/AaltoSciComp/video-editlists-asc

Summary

• Basic principle: privacy is more important than any other factor. If we can’t guarantee privacy, we can’t release videos at all.

  • Disclaimers such as “if you don’t want to appear in a recording, leave your video off and don’t say anything”, since a) accidents happen especially when coming back from breakout rooms. b) it creates an incentive to not interact or participate in the course.

• Livestreaming is important here: by separating the instruction from the audience audio/video, there is no privacy risk in the raw recording. They could be released or shared unprocessed.

• Our overall priorities

  1. No learner (or anyone not staff) video, audio, names, etc. are present in the recordings.

  2. Good descriptions.

  3. Removing breaks and other dead time.

  4. Splitting videos into useful chunks (e.g. per-episode), perhaps equal with the next one:

  5. Good Table of Contents information so learners can jump to the right spots (this also helps with “good description”.)

• ffmpeg-editlist allows us to define an edit in a text file (crowdsourceable on Github), and then generate videos very quickly.

Exercises

Use ffmpeg-editlist to edit this sample video

Prerequisites: ffmpeg must be installed on your computer outside of Python. Be able to install ffmpeg-editlist. This is simple in a Python virtual environment, but if not the only dependency is PyYAML.

• Download the sample video: http://users.aalto.fi/~darstr1/sample-video-to-edit.raw.mkv

• Copy a sample editlist YAML

• Modify it to cut out the dead time at the beginning and the end.

• If desired, add a description and table-of-contents to the video.

• Run ffmpeg-editlist to produce a processed video.

Solution

- input: sample-video-to-edit.raw.mkv
- output: sample-video-to-edit.processed.mkv
  description: >
  editlist:
    - start: 00:16
    - 00:15: demonstration
    - 00:20: discussion
    - stop: 00:25

$ ffmpeg-editlist editlist.yaml video/ -o video/

Along with the processed video, we get sample-video-to-edit.processed.mkv.info.txt:

This is a sample video


00:00 Demonstration
00:04 Discussion

See also

(none yet)