GIMP by Ciro Santilli 37 Updated 2025-07-16
It's not super easy to use at first.
And it sometimes says that the basic drawing thing you want to do is off the project's scope.
But as you learn more about it and further generalize the concepts, there are often reasonable reasons for those design choices.
And the UI looks good :-)
Examples:
Kdenlive by Ciro Santilli 37 Updated 2025-07-16
This seems like a decent option, although it has bugs coming in and out all the time! Also it is quite hard to learn to use.
To get started:
  • import a clip
  • drag it onto the track area
Shortucts:
To set the video length, search for "set outpoint" on "monitor".
Add subtitles:
  • Effects
  • Dynamic text
then drag on top of the video track. To add only to part of the video, cut it up first.
Preview has no sound on Ubuntu 20.10. Fixed as of Ubuntu 22.04.
Sound worked on Ubuntu 21.04 though, but it then soon crashed with:
 = = SET EFFECT PARAM:  "rect"  =  0=1188 0 732 242
MUTEX LOCK!!!!!!!!!!!! slotactivateeffect:  1
// // // RESULTING REQUIRED SCENE:  1
Object 0x557293592da0 destroyed while one of its QML signal handlers is in progress.
Most likely the object was deleted synchronously (use QObject::deleteLater() instead), or the application is running a nested event loop.
This behavior is NOT supported!
qrc:/qml/EffectToolBar.qml:80: function() { [native code] }
Killed
amazing.
On Ubuntu 22.04 haven't crashed yet.
OpenShot by Ciro Santilli 37 Updated 2025-07-16
Ubuntu 20.10 crash...:
  exceptions:ERROR Unhandled Exception
Traceback (most recent call last):
  File "/usr/bin/openshot-qt", line 11, in <module>
    load_entry_point('openshot-qt==2.5.1', 'gui_scripts', 'openshot-qt')()
  File "/usr/lib/python3/dist-packages/openshot_qt/launch.py", line 97, in main
    app = OpenShotApp(argv)
  File "/usr/lib/python3/dist-packages/openshot_qt/classes/app.py", line 218, in __init__
    from windows.main_window import MainWindow
  File "/usr/lib/python3/dist-packages/openshot_qt/windows/main_window.py", line 45, in <module>
    from windows.views.timeline_webview import TimelineWebView
  File "/usr/lib/python3/dist-packages/openshot_qt/windows/views/timeline_webview.py", line 42, in <module>
    from PyQt5.QtWebKitWidgets import QWebView
ImportError: /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5: undefined symbol: _ZN4QRhi10newSamplerEN11QRhiSampler6FilterES1_S1_NS0_11AddressModeES2_, version Qt_5_PRIVATE_API
On Ubuntu 20.10, just:
ffmpeg -i input.mp4 -vf "subtitles=subtitle.srt" output.mp4
To change font size: stackoverflow.com/questions/21363334/how-to-add-font-size-in-subtitles-in-ffmpeg-video-filter
ffmpeg -i input.mp4 -vf "subtitles=subtitle.srt:force_style='Fontsize=64'" output.mp4
The default appears to be 24, so just multiply that by whatever seems like a reasonable factor.
Note howver that .ass subtitle files can contain style information, which ffmpeg respects. Aegisub can produce and preview such styles, making .ass one of the best options.
Aegisub by Ciro Santilli 37 Updated 2025-07-16
This worked well on 3.2.2 Ubuntu 20.10. Recommended.
First import video with:
aegisub-3.2 ourbigbook-parent.mkv
They don't have an aegisub executable without the version number. Amazing.
If you already have a subtitle file that you want to edit, then just pass it on as well:
aegisub-3.2 ourbigbook-parent.mkv ourbigbook-parent.ass
Ctrl + P: play and pause video.
Ctrl + 3: set current substitle start time.
Ctrl + 4: set current substitle end time.
Enter: finish editing the current entry and start a new one.
kitone/subtitleeditor by Ciro Santilli 37 Updated 2025-07-16
Not to be confused with Subtitle Edit.
As of 0.54.0 this feels featureful, but extremely buggy or lacking UI obvious enhancements that would be simple to implement, and offer huge value:
It is hard to understand how that project reached this weird featureful but crappy state. Feels like they just gave push permission to a bunch of random people.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact