Glad you reminded me. Returned just this weekend to my editing station. Just downloaded your dropbox files and tried them.
First, your original file. It plays OK in MPC-HC and Windows Media Player. However, I get the same problem in Vegas. It just hangs and I have to end Vegas in Task Manager. I also tried opening the file in VideoReDo and TMPGEnc’s Smart Renderer, both designed to smart-render AVC files. In both cases, the file would not open. VideoReDo gave an error message and TMPGEnc just hung like Vegas. Again, my suspicion is that your file was recorded using a variable frame rate. I found another thread of mine where I tried recording to an MP4 using Mirillis Action with their Quick-Sync option. The result was also a variable frame rate file which would not open in Vegas, but had to be re-rendered in Handbrake. Files recorded to an AVI were OK. The bottom line is that you need to find some recorder that produces constant frame rate files which can be directly imported into Vegas. Otherwise, you are stuck with transcoding using Handbrake or something similar.
Your second project using the Handbrake file opened without issue. Render preview on Best/Full was pretty much pegged at 60 fps, even that portion where there were changes in the velocity envelope. In other words, no problem at all.
My suggestion is that you continue a search to find something that “works” for direct import into Vegas. I would try recording to an AVI, since it is my understanding that an AVI is always a constant frame rate. Having said that, I’ve seen some posts about problems with AVI’s using OBS. As I’ve said before, this problem seems to be very common and as of yet, I’ve seen no solution, other than transcoding. If you do find something, please post back. Good luck again.
wwaag