Thanks Roger. Sure, the issues I'm having are terrible timeline playback (like 2 frames per second) and Vegas won't open projects that have multiple DJI files in them. It just hangs forever. If I disable the GPU in the settings, Vegas works and no longer hangs, but then the GPU is disabled so that's not a great option.

I do realize that the Canon and DJI are different file types but they both use the so4compounddll and I'm certain that's the culprit. The Canon only uses Motion JPEG for 4K files and I transcode those files anyway. The files I'm dealing with from the Canon are only HD. They're .mov files but like the DJI files, they are listed as AVC .mov in Vegas.

Also, I do have the latest Studio Driver installed.

I did some more tests and it seems like two scenarios seem to fix my issues. 1) If I change the "hardware decoder for so4 compound dll" to a O in internal settings. Or 2) changing all the internal settings back to default while enabling the legacy AVC decoder in Internal settings.

But, I'm wondering if I should be using these in conjunction or are there other settings that should also be changed since there are multiple options of dealing with the so4compound dll. Basically I'm just trying to figure out how to get optimal playback.

This is good to clarify.

so4compound isn't something bad to be disabled as a first step. It provides modern decoding for a wide variety of files and enables both GPU hardware to be leveraged as well as support for 10-bit formats. Disable it and you disable these features. You can disable it by checking enabling legacy AVC decoding, which is a front-end for the internal preferences you are also changing.

In your case I think you need to isolate the problem. Try the Canon AVC files alone. They should work fine with so4compound and all settings on default. I don't have Mark IV files but used older Canon HD AVC .movs without issue. Feel free to upload a sample if there's something unusual about it. If even this doesn't work there's something else amiss with the settings in Vegas.

The most likely problem is the DJI files. Can you provide MediaInfo for exactly what these are? https://mediaarea.net/en/MediaInfo

Others who use DJI may have ideas for best settings in the device and Vegas.

Of course if you're already used to transcoding, you could try transcoding them to a better format for editing until Vegas support improves.

@jimingo-1 There is an issue with mjpeg file from Canon 4k files, once you try to load ~ 40 plus, not sure if it applies to FHD. The latest update, HOS version, just released, from @wwaag handles mjpeg in an AVI container. I’m not sure if he means by that that the mjpeg files are converted into an AVI container, or that if they are already in one, and he now supports that.

@jimingo-1 I am using DJI Pocket 2 AVC files (3840x2160 at 25p/s and 50p/s) in VEGAS 18 without any issue. I assume that they have a similar file format. I have an NVIDIA 1060 6Gbyte card. This card is using a Pascal chip while your card has a Turing chip. So there might be an issue with your grafic card support in so4compoundplug.dll

@jimingo-1 I can import and edit DJI Osmo Pocket 2160p24 ((3840x2160 at 23.976fps) with Vpro18 and VMS17 without issues.