Does disabling so4compound in internal preferences help? I recall Vegas from that era having issues with DJI and GoPro. Newer versions of Vegas should work better.

Thanks for answers, looks like older Sony Vegas not working with this files. Sadly i can't test Vegas 19 PRO, Trial mode is not active - i never installed new version :|

My config is i5-8400, GTX1070, 8 GB RAM. I have also Magix Photostory Deluxe and it's working great with this config, so it's software related problem, but it doesn't have split video files options.

I'm disappointed by Vegas, can You recommend me some program which really works with high resolution materials and it's simple in usage? Not Magix :|

You could try disabling so4compoundplug: https://www.vegascreativesoftware.info/us/forum/avc-xavc-s-issues-in-vp15-16-try-disabling-so4compoundplug-dll--108345/

If that works then it's actually better to use the so4 blacklist so that you are only disabling so4compoundplug for specific formats: https://www.vegascreativesoftware.info/us/forum/blacklist-for-so4-includes-fix-for-gopro-dji-xiaomi-yi-avc-lag--111716/

This is my actual so4_blaclist_vp15.xml file that I am using in VP15/16/17. Note the 2 lines relating to GoPro AVC, because the first one does not work for all GoPro AVC formats:

<?xml version="1.0" encoding="utf-8"?>
<filter_expr type="OR" comment="exclude IDR/I files where M = 1">
    <video Title="DJI.AVC" />
    <video Title="GoPro AVC" />
    <video Title="XiaoYi AVC   " />
    <!-- Formats below added by user -->
    <video Title="  GoPro AVC / GoPro AVC" />
    <!-- I think so4-decoding of XAVC-S can no longer be disabled with the line below in VP18 -->
    <!-- <general Format="XAVC" /> -->
</filter_expr>

If your files are HEVC then this won't help at all.

Thanks for Your answer Nick, but stills nothing. I click single file and have to wait 3 minutest before program allows me drag this file to timeline :/

Trial mode is not active - i never installed new version

If you haven't installed and activated the trial version of Vegas Pro 19, I would have thought that the trial version period hasn't commenced. Give it a try.

But ... in Vegas Pro 19, a minimum of 32 GB RAM is needed for 4K, so 5.3K may also need that as a minimum.

@Dawid-Wyka
With my Vegas 15 I can use with ease the DJI and GOPro 7 files upto UHD 50p, but I don't have your type of file.
I like to test that one but therefore you have to upload a short problem file to a location where I can download it as it is.

Here is example of this file -> https://mega.nz/file/KR4gRbaS#nJ0cLDo7eOBjjiJdNxImnvsU9BHCQWxE7AhWA_w6eDw

Hello all,

I have problem with opening 5.3k 60fps files from gopro. When i try open few files program freezes and stop working. Vegas 15 PRO. Processor usage is low, application not responding. Even single file opening is long and i have wait few minutes :(

 

These files are quite heavy for your PC, I'm not sure if VP15 creates already automatically proxies when importing such files. Creating proxies takes some time but enable that you can edit such files.

@Dawid-Wyka
No problems with those files in Vegas Pro 15 latest build on my desktop from signature
Because the program can not use projects higher than UHD it makes a black bar for the preview to show this file. Look how it goes there with your file

I tested also with Vegas 19 on laptop from signature.
Not a problem at all, look

I don't have VP15, but it Autobuilds Proxies on 18 and 19.

I suspect that is what your VP15 is doing, and it takes quite a while, but you only have to do it once.

Unless you plan on waiting all night, don't open 60 files at once!

With your system, I wouldn't think of trying to edit without proxies.

@Dawid-Wyka
No problems with those files in Vegas Pro 15 latest build on my desktop from signature

 

I tested also with Vegas 19 on laptop from signature.
Not a problem at all, look

 

Looks very hopefully for @Dawid-Wyka....

I just reinstalled VP15 and imported your Gopro HEVC coded file, VP15 needs internet connection to activate HEVC codec, which is also only possible when VP15 is (officially) registered. VP15 has the option to generate proxies, which would enable fluent previewing of such files. VP15 has a max resolution restriction of 4096x4096, so 5312x2988 is not possible (as @j-v already showed), but only 4096x2988.

Therefore someting must be wrong in the settings for the program of @Dawid-Wyka

It has nothing to do with the So4 plugin because in my both versions the mxhevcplug is used.

@Dawid-Wyka
Can you give screenshots of Options/Preferences/Editing and Options/PreferencesVideo at your installation?

Does not appear to create proxy on VP17/19 on laptop (auto create set ON). Can create proxy via HOS.

Laptop Spec in signature

This is not about fluent play but about not opening

Thanks j-v for Your answer, looks like it's problem of my installation, no vegas 15 overall. I will upgrade to Win11 sook in new installation, maybe then it will work. Here are screenshots from my settings, of course it's not about fluent play, when i click on file in open or expolorer built in program, program freezes for few minutes.

Can it be a "Steam"- problem?

Hard to say :( I installed Vegas 19 PRO and it works great. Is there any direct contact to Magix support? I'm searching and no succes :(

VEGAS Support.