Preview (and export) frame by frame SLOW

[Jesse Pink]

I really don't even know how to describe this. I'm a brand new user to OpenShot but not to other or linear editors. Basically, all I have done is drag in ONE video (which was recorded using OBS at 720p, 60fps in mkv/h.264 format).

My uncut video is 1 hour, 16 minutes long-- the timeline shows the correct length of the video, however if I set my "current position" to like the 60 minute mark, the video has only advanced like 30 seconds. Clicking play on the preview also doesn't really do much, it may advance it a second every 30 seconds or so, but it's hard to say exactly.

I cut the video down to ~12 minutes and exported it, thinking that it was just the preview window that wasn't working for me, but unfortunately the exported video looks exactly the same as what I was witnessing in the program itself. Here's a link to the video after uploading to youtube: https://youtu.be/8ZcVnnrpXy8

I'm using Windows 10 Pro v1709
I installed it from the Windows installer package downloaded from the main website, and is 2.4.1.

I don't have MLT/melt, nor BZR as I think those may be primarily Linux applications?

Here is another demonstration video of what I'm seeing in the problem itself... https://youtu.be/C1fcxnxQEGs

Let me know what else you may need from me (outside of MLT, as I do not have it.)

[Jesse Pink (jlink7)]

It appears that maybe it's the video file itself that was generated by OBS... I used another video file that I got from youtube and the preview works fine.

[Jesse Pink (jlink7)]

Ok, last thing... I just used OBS's feature to "remux" the mkv output container to mp4, and it now works in openshot without issue. Obviously the "video" inside the container is still the same, it's just that OpenShot does not like the mkv container?