Here are some notes on how to use OBS Studio for screen recording, and then use iMovie to try to edit the video.
There are a couple of issues that I had to solve
- convert from flv to mp4 format for iMovie
- import the audio track into iMovie
- change the speed of the video in iMovie
- top of the video not showing up in iMovie
- how to remove part of a video in iMovie
- increase the volume of the audio track
I used the “window capture” functionality in OBS studio.
Convert from flv to mp4 format for iMovie
By default, OBS saves the file to .flv format, which is not supported by iMovie. I first tried to use vlc player to convert it to .mp4 format, which is supported by iMovie. However, I realized that the video is time is corrupted and my 1 min video ended up being around 38 min when imported into iMovie. This makes it impossible to edit the imported media in iMovie.
I tried a few other formats and options in vlc player but to no avail. I didn’t bother to download a series of free video conversion software as I am hesitant of installing a lot of random softwares on my laptop.
In the end, I found this post was really helpful (https://obsproject.com/forum/resources/how-to-convert-flvs-to-mp4-fast-without-re-encoding.78/) . You can actually use the “remux” functionality (under “File”) in OBS studio to convert .flv files into .mp4 files. This time, the imported time is correct (~ 1 min), and I was able to make edits. Apparently, you can set the output to be .mp4 files directly.
Import the audio track into iMovie
However, I run into anther issue that the OBS studio converted video’s sound could not be imported into iMovie. I ended up just using QuickTime player to open the .mp4 file (QuickTime player apparently can play the video with audio / sound), and clicked “File”, “Export As” an “Audio Only” file. Then iMovie could import the audio only file and play the sound.
Change the speed of the video
On the small window in the top right (where you can click play), on the top there is a panel that has a speed meter sign. Click it, and then you can customize the speed.
Top of the video not showing up in iMovie
Need to set up the “Crop” correctly. Be default, it crops the center of some videos. You can use the “fit” option to fit the entire vide.
How to remove part of a video in iMovie
Select the time you want to start, hold down “R”, and then drag to the end of the clip, “Ctrl + click”, select delete, and the clip will be deleted.
Increase the volume of the audio track
You can hover over the waveform (soundtrack) in the iMovie panel and drag a horizontal line up to boost the volume of the video. This can boost the volume level by up to 400%.